How Trees Have Evolved to Obtain Light and Photosynthesize at the Greatest Rate

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备战2021年高三英语纠错笔记系列专题11阅读理解（含解析）

专题11 阅读理解易错点1 只见树木不见丛林，误把细节当主题〔2021·新课标III卷〕Cities usually have a good reason for being where they are, like a nearby port or river. People settle in these places because they are easy to get to and naturally suited to communications and trade. New York City, for example, is near a large harbour at the mouth of the Hudson River. Over 300 years its population grew gradually from 800 people to 8 million. But not all cities develop slowly over a long period of time. Boom towns grow from nothing almost overnight. In 1896, Dawson, Canada, was unmapped wilderness(荒原). But gold was discovered there in 1897, and two years later, it was one of the largest cities in the West, with a population of 30,000.Dawson did not have any of the natural conveniences of cities like London or Paris. People went there for gold. They travelled over snow-covered mountains and sailed hundreds of miles up icy rivers. The path to Dawson was covered with thirty feet of wet snow that could fall without warming. An avalanche(雪崩) once closed the path, killing 63 people. For many who made it to Dawson, however, the rewards were worth the difficult trip. Of the first 20,000 people who dug for gold, 4,000 got rich. About 100 of these stayed rich men for the rest of their lives.But no matter how rich they were, Dawson was never comfortable. Necessities like food and wood were very expensive. But soon, the gold that Dawson depended on had all been found. The city was crowded with disappointed people with no interest in settling down, and when they heard there were new gold discoveries in Alaska, they left Dawson City as quickly as they had come. T oday, people still come and go — to see where the Canadian gold rush happened. T ourism is now the chief industry of Dawson City — its present population is 762.27. What is the text mainly about?A. The rise and fall of a city.B. The gold rush in Canada.C. Journeys into the wilderness.D. T ourism in Dawson.【错因分析】一篇文章都是围绕着一个中心思想或一个话题展开的，因此，有的文章中最明显的特点之一是有一个反复出现的中心词，即高频词，也叫做主题辞。

托福TPO45综合写作阅读原文+听力原文+满分范文

托福TPO45综合写作阅读原文+听力原文+满分范文为了帮助大家高效备考托福，为大家带来托福TPO45综合写作阅读原文+听力原文+满分范文，希望对大家备考有所帮助。

托福TPO45综合写作阅读原文文本：Did bees (a type of insect) exist on Earth as early as 200 million years ago? Such a theory is supported by the discovery of very old fossil structures that resemble bee nests. The structures have been found inside 200- million-year-old fossilized trees in the state of Arizona in the southwestern United States. However, many skeptics doubt that the structures were created by bees. The skeptics support their view with several arguments. No Fossils of Actual Bees First, no fossil remains of actual bees have ever been found that date to 200 million years ago. The earliest preserved body of a bee is 100 million years old—only half as old as the fossilized structures discovered in Arizona. Absence of Flowering Plants A second reason to doubt that bees existed 200 million years ago is the absence of flowering plants in that period. T oday's bees feed almost exclusively on the flowers of flowering plants; in fact, bees and flowering plants have evolved a close, mutually dependent biological relationship. Flowering plants, however, first appeared on Earth 125 million years ago. Given the bees’ close association with flowering plants, it is unlikely bees could have existed before that time. Structures Lack Some Details Third, while the fossilized structures found in Arizona are somewhat similar to nest chambers made by modern bees, they lack some of t he finer details of bees’ nests. For example, chambers of modern bee nests are closed by caps that have a spiral pattern, but the fossilized chambers lack such caps. That suggests thefossilized structures were made by other insects, such as wood-boring beetles.托福TPO45综合写作听力原文文本：ProfessorIt's perfectly possible that the nests found inside the fossilized trees were made by bees 200 million years ago. The arguments used by the skeptics are not convincing.First, it's true we have no fossil remains of actual bees that date to 200 million years ago, but maybe the reason for that is that bees could not be preserved as fossils at that time. Fossil bees have typically been preserved in fossilized tree resin, a sticky liquid produced by trees. However, trees with this type of resin were very rare 200 million years ago. Such trees became common much later. So the fact that we have no bee remains that are 200 million years old doesn't mean that bees did not exist at that time. Maybe bees existed, but since there were almost no trees producing the right kind of resin, the bees could not be preserved.Second, while it's true that bees have a close mutual relationship with flowering plants today, it's quite possible that bees existed before flowering plants appeared on Earth. Those very early bees might have been feeding on non-flowering plants thatpreceded flowering plants during evolutionary history. The early bees could have fed on non- flowering plants such as ferns or pine trees. Later when flowering plants evolved, bees may have adapted to feeding on them! And this new relationship between bees and flowering plants may have remained stable ever since.Third, even though the fossilized chambers lack spiral caps, there's chemical evidence that supports the theory that bees built the chambers. Modern bees protect their nest chambers againstwater by using a special waterproofing substance that has a distinctive chemical composition. When the fossilized chambers were chemically analyzed, it turned out that they contain the same kind of waterproofing material that's used by modern bees.托福TPO45综合写作满分范文：In the lecture, the professor casts doubt on the reading passage’s idea that the nests found inside the fossilized trees were not created by bees. The professor asserts that the arguments used in the reading are not convincing. T o begin with, according to the reading passage, no fossil remains of actual bees have been found that date to 200 million years ago. The professor argues that no bee remains that are 200 million years old doesn’t mean that bees didn’t exist at that time. He says maybe bees couldn’t be preserved as fossils at that time. Since there were almost no trees producing the right kind of resin, a sticky liquid produced by trees, the bees could not be preserved. On top of that, the reading passage states that flowering plants were in absence 200 million years ago. On the contrary, the professor claims that it’s quite possible that bees existed before flowering plants appeared on Earth. The professor points out that early bees might have been feeding on non-flowering plants that preceded flowering plants during evolutionary history. Later when flowering plants evolved, bees may have adapted to feeding on them. And this new relationship between bees and flowering plants have remained stable ever since. Lastly, the professor rebuts the reading’s point that the fossilized structures lack some of the finer details of bees’ nests such as the chambers lacking caps by stating that there’s chemical evidence that supports the theory that bees built the chambers. The professor points out that when the fossilized chambers werechemically analyzed, it turned out that they contain the same kind of waterproofing material that’s used by modern bees.以上是给大家整理的托福TPO45综合写作阅读原文+听力原文+满分范文，希望对你有所帮助!。

2021届辽宁省_高二英语试题_上学期英语期末试题分类汇编：七选五专题及答案

七选五专题辽宁省沈阳市郊联体2020-2021学年高二上学期期末英语试题第二节（共5小题；每小题2.5分，满分12.5分）根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。

选项中有两项为多余选项。

As a species,ginkgo(银杏）trees, which enjoy a reputation as "The Tree that Time Forgor", have existed relatively unchanged for 200 million years.While scientists have revealed the mysteries of the tree's long life, it won't help humans soon.Scientists in China examined the genetic component of very young ginkgo trees,comparing samples between several hundred and a thousand years old.___16___The scientists also found that, unlike other plants, ginkgo genes with regard to aging do not automatically become active at a certain stage in their life cycle.___17___This explains why old ginkgo trees produce as many seeds as young ones and how they continue to grow wide for as long as they live.Furthermore,ginkgo trees are born with protective biochemical characteristics,in the form of hormones, antioxidants, and bactericides.___18___Also, they have evolved adaptations that enable them to resist pests and climate extremes.___19___Over time,weather and other factors limit upright growth and cause leaves to die.Yet,even as this aging occurs, the cell-reproducing system of the gingko tree remains active, maintaining healthy growth.Growth typically starts slowing down after 200 years, but the trees remain healthy.Each year, they renew their parts, adding new wood,leaves, roots, and reproductive organs.In theory,gingko trees shouldlive forever.___20___A. Of course,these trees do age, to some extent.B. Their immune systems were found to be similar.C. That is, ginkgo trees have no genetic program for death.D. All of these strengthen their resistance to diseases and bacteria.E. While they contain minor poison, humans still eat their fruits for health reasons.F. However,ginkgo trees still die from pests,drought,and other damaging events.G. They have survived some greatest catastrophes, such as the extinction of the dinosaurs.【答案】16. B 17. C 18. D 19. A 20. F【解析】本文是一篇说明文。

南京大学英语网测

.第一学期unit1自测（不计分）(测试层次:总分: 100 / 测试时长:120分钟) 已完成:0(60) 已用时间:0:00:12 / 剩余时间: 1:59:48 读写教程unit1 1. On the ninth tee, he ________ the landscape: scrawny trees, dying grass, and sand.(2.0分)2. When she was a girl, the ______ had cut her hands, but picking this new cotton was fun.(1.0分)A.fluffsB.thornsC.burrsD.flurs3. No one could possibly understand how overwhelmed Frost was ______ the memories which flooded up as he read.(2.0分)4. As she took the notes out of a desk drawer and gave them to me, I felt great excitement in the knowledge that, almost by accident, I held the earliest known writing of a major literary _______.(2.0分)5. As an awkward 12-year-old he wrote her ardent notes, but the young lady had many other admirers and did not encourage him.(2.0分)A.弗罗斯特十二岁那年，羞怯腼腆的他给萨布拉写了几封火热的短信。

可当时这位年轻的女士崇拜另外的人，她没给弗罗斯特什么希望。

小学上册第1次英语能力测评(有答案)

小学上册英语能力测评(有答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The ______ helps us learn about cultural awareness.2.ts have evolved to resist ______ and survive in challenging conditions. (某些植物已进化以抵抗病虫害，在艰难的条件下生存。

) Some pla3.My favorite exercise is ______.4.My favorite sport is ______ (volleyball).5.__________ are used in the production of biofuels.6.The __________ in the air feels fresh after the rain. (气息)7.Chemicals can change color when they undergo a ______.8.Roses are known for their beautiful ______. (玫瑰以其美丽的花朵而闻名。

)9.I dream of having a ________ (玩具名) that can ________ (动词) by itself. That would be so ________ (形容词)!10.The kestrel is a small ______ (猛禽).11.I can jump over ______.12.The __________ (历史的沉淀) allows for reflection.13.The cake is _____ with sprinkles. (topped)14.The process of ______ can reveal hidden geological structures.15.Chemical reactions can produce light, sound, or _____.16. A bear can climb ______ (树木).17.We will _______ (meet) at the café.18.What do we call the hard outer covering of an egg?A. ShellB. YolkC. WhiteD. Albumen答案: A. Shell19.Learning about plant relationships can deepen your appreciation for ______. (了解植物之间的关系可以加深你对自然的欣赏。

英语作文喂食野生动物的

英语作文喂食野生动物的Feeding Wild Animals: A Concerning TrendThe great outdoors offer a captivating glimpse into the natural world, where diverse species of wildlife thrive in their native habitats. From majestic bears foraging in the dense forests to playful squirrels scurrying up towering trees, these animals are an integral part of the delicate ecosystem. However, in recent years, there has been a growing trend of individuals actively engaging in the feeding of wild animals. While the intention may stem from a desire to connect with nature or provide sustenance, this practice poses significant risks to both the animals and the environment.One of the primary concerns with feeding wild animals is the potential disruption to their natural behaviors and feeding patterns. Wild animals have evolved over centuries to obtain their sustenance through foraging, hunting, or scavenging in their designated territories. By introducing human-provided food sources, we inadvertently interfere with this natural process, causing the animals to become dependent on these artificial means of sustenance. Thisdependency can have far-reaching consequences, as the animals may become less inclined to seek out their natural food sources, leading to a decline in their foraging skills and overall fitness.Moreover, the food items that humans provide to wild animals are often not aligned with their natural dietary requirements. Many well-intentioned individuals may offer processed, high-calorie, or even unhealthy snacks to these animals, unaware of the detrimental effects it can have on their health. Consuming such unsuitable foods can lead to nutritional imbalances, digestive issues, and even the development of chronic diseases in the animals. This can ultimately compromise their overall well-being and, in severe cases, result in premature death.Another significant concern with feeding wild animals is the potential for the spread of diseases and the introduction of non-native species. When humans interact with wild animals, they inadvertently create opportunities for the transmission of pathogens and the inadvertent release of non-native species into the ecosystem. These introduced species can disrupt the delicate balance of the local environment, outcompeting native species for resources and altering the natural food web. This can have cascading effects on the entire ecosystem, leading to the decline or even extinction of indigenous species.Furthermore, the act of feeding wild animals can also pose a threatto human safety. Many wild animals, even those perceived as docile, can become unpredictable and aggressive when they associate humans with a reliable food source. This can lead to dangerous encounters, where the animals may become more bold and approach humans in search of food, potentially resulting in injuries or even fatalities.In addition to the risks to the animals and the environment, feeding wild animals can also have legal implications. In many regions, it is illegal to feed wild animals, as it is considered a form of wildlife interference or disturbance. Individuals who engage in this practice may face fines or other legal consequences, depending on the local regulations.Despite these compelling reasons to avoid feeding wild animals, the allure of interacting with these creatures in their natural habitats remains strong. However, the responsible approach is to appreciate and observe wildlife from a safe distance, allowing them to thrive in their natural ecosystems without human intervention. This can be achieved through educational initiatives, eco-tourism, and the promotion of conservation efforts that prioritize the protection of wildlife and their habitats.In conclusion, the practice of feeding wild animals, while seemingly harmless, can have far-reaching and detrimental consequences. Itdisrupts the natural behaviors and feeding patterns of the animals, compromises their health, and poses risks to both the environment and human safety. By understanding the importance of respecting the boundaries between humans and wild animals, we can play a crucial role in preserving the delicate balance of our natural world and ensuring the long-term well-being of these magnificent creatures. The responsibility lies with us, as stewards of the environment, to educate ourselves, modify our behaviors, and advocate for the protection of wildlife and their habitats.。

真核生物英语

真核生物英语Eukaryotes: The Diverse and Complex Organisms that Dominate the Biological WorldEukaryotes, a term derived from the Greek words "eu" meaning "true" and "karyon" meaning "nucleus," are a group of organisms that are characterized by the presence of a true nucleus within their cells. This defining feature sets them apart from the other major domain of life, the prokaryotes, which lack a distinct nuclear membrane. Eukaryotes encompass a vast and diverse array of organisms, ranging from single-celled microbes to the towering trees and majestic mammals that populate our planet.At the heart of eukaryotic cells lies the nucleus, a membrane-bound organelle that houses the genetic material, or DNA, of the cell. This genetic information is organized into linear structures called chromosomes, which are further compacted and organized within the nucleus. The presence of a true nucleus allows for the compartmentalization of various cellular processes, enabling a higher level of complexity and specialization within eukaryotic cells.Beyond the nucleus, eukaryotic cells are characterized by thepresence of numerous other membrane-bound organelles, each with its own specialized function. These organelles include the endoplasmic reticulum, which is responsible for the synthesis and transport of proteins; the Golgi apparatus, which modifies and packages these proteins for distribution; and the mitochondria, which serve as the "powerhouses" of the cell, generating the energy-rich molecule ATP through the process of cellular respiration.One of the most striking features of eukaryotic cells is the presence of a cytoskeleton, a network of filamentous structures that provide structural support, facilitate intracellular transport, and enable cellular movement. This cytoskeleton is composed of three main types of filaments: microfilaments, intermediate filaments, and microtubules, each with their own unique properties and functions.Eukaryotes can be broadly divided into several major groups, including plants, animals, fungi, and protists. Each of these groups has its own distinct characteristics and evolutionary histories, but they all share the fundamental features that define the eukaryotic domain of life.The plant kingdom, for example, is characterized by the presence of chloroplasts, organelles that house the photosynthetic machinery responsible for converting sunlight, carbon dioxide, and water into glucose, the primary energy source for plant cells. Plants also possessa rigid cell wall made of cellulose, which provides structural support and protection.The animal kingdom, on the other hand, is defined by the presence of specialized cells that are capable of movement, such as muscle cells, and the ability to sense and respond to their environment, as exemplified by the complex nervous systems of many animals. Additionally, animal cells lack the rigid cell walls found in plants, instead possessing a more flexible cell membrane.Fungi, while often overlooked, play a crucial role in the global ecosystem. These organisms are characterized by the presence of chitin-based cell walls and the ability to obtain nutrients through the secretion of digestive enzymes and the absorption of the resulting molecules. Fungi can be found in a wide range of habitats, from the deep ocean to the highest mountain peaks, and they play vital roles in decomposition, nutrient cycling, and the formation of symbiotic relationships with other organisms.Protists, the most diverse and heterogeneous group of eukaryotes, encompass a wide range of single-celled organisms that do not fit neatly into the plant, animal, or fungal kingdoms. This group includes a variety of algae, protozoa, and slime molds, each with their own unique adaptations and ecological niches.The diversity of eukaryotic organisms is truly astounding, with estimates suggesting that there may be as many as 8.7 million species on Earth, the vast majority of which are yet to be discovered and described. This remarkable diversity is a testament to the evolutionary success of the eukaryotic domain, which has adapted to thrive in a wide range of environments and ecological niches.One of the key factors that has contributed to the success of eukaryotes is the development of sexual reproduction, a process that involves the fusion of two haploid cells to form a diploid zygote. This process allows for the shuffling of genetic material, creating genetic diversity and enabling the rapid adaptation of eukaryotic organisms to changing environmental conditions.Moreover, the complexity of eukaryotic cells, with their intricate organelles and specialized functions, has allowed for the evolution of multicellular organisms, which can coordinate the activities of individual cells to form complex tissues, organs, and systems. This level of organization has enabled the development of highly specialized and sophisticated life forms, such as the towering trees of the rainforest and the intricate neural networks of the human brain.Despite their diversity and complexity, eukaryotes face a range of challenges in the modern world. Environmental degradation, habitat loss, and the spread of disease have all contributed to the decline ofmany eukaryotic species, highlighting the fragility of the delicate balance that sustains life on our planet.In conclusion, the eukaryotic domain of life is a testament to the incredible diversity and complexity of the biological world. From the single-celled protists to the majestic mammals, eukaryotes have evolved to thrive in a wide range of environments, demonstrating the remarkable adaptability and resilience of life. As we continue to explore and understand the intricate workings of these remarkable organisms, we gain a deeper appreciation for the wonders of the natural world and the importance of preserving the delicate balance that sustains it.。

专业英语与一般英语的区别省名师优质课赛课获奖课件市赛课一等奖课件

12
mis- : miscount mistake
Multi-,poly-: multipurpose, multicarrier polynomial(binomial)
non-: linear->nonlinear effective->noneffective
post-: postfix postgraduate
8
8) 较多使用祈使语气 e.g. Let the forward-pass transfer function be given
by the linear difference equation. 9) 句中并列成份（多种并列短语、单词或从句）较
多 e.g. Radar has certain inherent advantages over
6. Ethernet hubs and switches provide an easy and inexpensive means to provide more bandwidth to workstations. (infinitive)
5
3) 精确（Accuracy)
long sentences ->exceedingly informative conditional sentences -> accurate description
a current to flow in opposition to the force producing it. 2) The invention of radio has made it possible for mankind to communicate with each other over a long distance.

小学上册第2次英语第三单元测验卷

小学上册英语第三单元测验卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the opposite of 'light'?A. BrightB. HeavyC. DarkD. Clear2.What is the name of the famous ocean that separates the Americas from Europe and Africa?A. PacificB. IndianC. AtlanticD. ArcticC3.What do we call a series of events in a story?A. PlotB. ThemeC. SettingD. CharacterA4. A ______ is a type of insect that can fly.5.I like to learn about ______ (科学技术) and how it shapes our lives. It’s essential in t oday’s world.6.We will have ______ for dinner tonight. (chicken)7. A tortoise's shell is made of ______ (骨头).8. A ______ can be found in many colors.9.We built a ________ out of blocks.10.I have a toy ________ that can fly.11. A chemical reaction that releases energy is called an ______.12.On hot summer days, I enjoy eating __________. (冰淇淋)13.What do you call the process of water falling from the sky?A. EvaporationB. PrecipitationC. CondensationD. CollectionB14. A ______ is a geological feature that can provide insights into the past.15.The __________ (历史的交织) illustrates interconnectedness.16. A solution is a homogeneous mixture of two or more ______.17.The __________ (花的颜色) can vary greatly among species.18.How many months are there in a year?A. 10B. 11C. 12D. 13C19.The flowers are ________ (香气扑鼻).20.The door is ________ open.21.The butterfly's wings are delicate and ______ (美丽).22.Which of these is a mammal?A. SharkB. DolphinC. GoldfishD. CrabB23.The __________ (历史的文化认同) informs practices.24.What is the name of the dinosaur with a long neck?A. Tyrannosaurus RexB. StegosaurusC. BrachiosaurusD. VelociraptorC25. A constellation is a group of stars that form a recognizable ______.26. A _______ can help to measure the speed of a moving vehicle.27.What do you call a person who teaches students?A. TeacherB. InstructorC. EducatorD. All of the aboveD28.What do we call the study of insects?A. EntomologyB. ZoologyC. BotanyD. AnthropologyA Entomology29. A reaction that occurs when an acid and a base combine produces ______.30.What is the name of the famous tree-dwelling marsupial from Australia?A. KoalaB. KangarooC. WallabyD. Wombat31.My brother has many __________ (爱好) he enjoys.32.The park is very ______. (big)33.The _______ (小百灵鸟) sings sweetly at sunset.34.The book is very ___ (interesting/boring).35.The chameleon changes color to _________. (伪装)36.The dog is ___ (digging/sitting).37.What is the largest mammal in the ocean?A. SharkB. DolphinC. Blue WhaleD. OctopusC38.What is the main purpose of a refrigerator?A. HeatB. Store foodC. CookD. Clean39.My _____ (滑梯) in the playground is very tall.40.The process of a liquid turning into a solid is called _______.41.My favorite thing about school is ________ (学习).42.Which food comes from a chicken?A. MilkB. EggsC. CheeseD. ButterB43.I like to ___ (jump/climb) trees.44.What do we call the act of preparing food?A. CookingB. BakingC. GrillingD. All of the AboveD45.The _____ (basket) is full of fruits.46.The kids are ___ (laughing).47.The flowers of a plant may have different shapes and ______. (植物的花朵可能有不同的形状和颜色。

生物的必需品英语的作文

生物的必需品英语的作文Living organisms whether they are plants animals or even microbes require certain necessities to survive and thrive in their environments These necessities are fundamental to the continued existence and well-being of all life forms on our planet Earth The most basic necessities that all living things need can be categorized into several key areas including food water shelter and living spaceFood is perhaps the most crucial necessity for all living organisms Food provides the energy and nutrients that organisms need to power their bodily functions grow and reproduce Different life forms have evolved to obtain food in a variety of ways Plants for example use photosynthesis to convert sunlight carbon dioxide and water into the glucose they need to survive while animals typically consume other organisms either plants or other animals to obtain the sustenance they require Microbes like bacteria and fungi often break down organic matter in their environments to extract the nutrients they need to live and growWater is another indispensable requirement for life All known livingorganisms require water to survive in some capacity Water makes up a large percentage of the body mass of most life forms and is involved in countless essential biological processes such as transporting nutrients and waste products facilitating chemical reactions and regulating body temperature Many organisms have specialized adaptations to obtain the water they need whether it is through root systems in plants drinking behaviors in animals or specialized water-trapping mechanisms in desert-dwelling creaturesShelter is also a critical necessity for the majority of living organisms Shelter provides protection from the elements predators and other environmental threats that could harm or kill an organism Shelters can take many forms such as burrows nests dens caves or even the physical structures that plants grow on their own Shelters allow organisms to conserve energy rest reproduce and carry out other important life functions in a safe and secure environmentFinally the availability of adequate living space is crucial for the survival and flourishing of all life forms Living space provides the physical area that organisms need to find food water shelter and other resources to meet their needs as well as room to move reproduce and interact with other members of their species and community Overcrowding or the loss of living space can lead to intense competition for resources stress and even the decline or extinction of a population or speciesWhen any one of these key necessities food water shelter or living space is lacking or compromised it can have severe consequences for the affected organisms Insufficient access to food and water for example can lead to malnutrition dehydration and ultimately death Lack of adequate shelter leaves organisms vulnerable to the elements and predation while limited living space can foster conflict competition and the degradation of the environment that sustains themFortunately the natural world has evolved over billions of years to provide the necessities of life for a incredible diversity of organisms from the smallest microbes to the largest whales and redwood trees Ecological systems and cycles ensure a general abundance and cycling of the resources that living things require to survive and thrive in their environments However the increasing human population and our unsustainable exploitation of natural resources is putting immense strain on the ability of the planet to continue meeting the basic needs of all lifeAs the dominant species on Earth humans have a great responsibility to be good stewards of the natural world and ensure that the necessities of life remain available not just for our own benefit but for all the other organisms with which we share this fragile planet We must find ways to meet our own needs for food water shelter andliving space in a sustainable manner that preserves the health and resilience of the global ecosystem on which all life depends Whether through the development of more efficient agricultural practices the protection of critical habitats the judicious use of natural resources or the adoption of renewable energy sources the choices we make as a species will profoundly impact the ability of the living world to continue providing the necessities that are fundamental to the persistence of life on Earth。

动植物话题作文思维导图英语

动植物话题作文思维导图英语Exploring the Interconnectedness of the Plant and Animal Kingdom through a Mind MapThe intricate web of life on our planet is a marvel to behold with its diverse array of plant and animal species coexisting in delicate balance. As we seek to understand the intricacies of this natural world, a mind map can serve as a powerful tool to visualize the complex relationships and interdependencies that exist between the realms of flora and fauna. By mapping out these connections, we can gain a deeper appreciation for the fragility and importance of maintaining the equilibrium of our ecosystems.At the heart of this mind map lies the fundamental understanding that plants and animals are inextricably linked. Plants, through the process of photosynthesis, serve as the primary producers in most terrestrial and aquatic environments, converting the sun's energy into the organic compounds that form the foundation of the food chain. Without these green giants, the entire food web would collapse, leaving the world devoid of the sustenance necessary tosupport the incredible diversity of animal life.Branching out from this central role, we can observe the myriad ways in which plants and animals interact and depend on one another. Herbivores, such as deer, rabbits, and caterpillars, consume plant matter, converting the nutrients into energy and biomass that sustains their own existence. In turn, these herbivores become prey for a wide range of carnivorous species, from majestic predators like lions and wolves to the more diminutive but no less important predators like spiders and birds of prey. This intricate web of predator-prey relationships not only maintains the balance of populations within an ecosystem but also facilitates the cycling of nutrients and energy, ensuring the continued vitality of the system as a whole.Delving deeper, we can explore the symbiotic relationships that have evolved between certain plant and animal species. Pollination, for instance, is a process that is vital for the reproduction of many flowering plants, with a vast array of insects, birds, and even some mammals playing pivotal roles as pollinators. The vibrant colors and alluring scents of flowers have evolved to attract these pollinators, who in turn benefit from the nectar and pollen they obtain. This mutually beneficial exchange is essential for the perpetuation of both plant and animal species, demonstrating the intricate dance of coevolution at play.Similarly, the process of seed dispersal is another area where plants and animals collaborate. Many plant species have developed ingenious mechanisms, such as burrs, hooks, or fleshy fruits, to ensure that their seeds are transported to new locations, often with the assistance of passing animals. Birds, mammals, and even aquatic creatures can all play a role in this process, inadvertently aiding in the propagation of plants and the establishment of new populations. This dynamic interaction not only benefits the plants but also provides food and habitat for the dispersing animals, further reinforcing the interdependence between the two kingdoms.Beyond these direct interactions, the influence of plants and animals extends into the broader realm of ecosystem services. Forests, for example, not only provide shelter and sustenance for a multitude of animal species but also play a vital role in regulating the climate, purifying water, and preventing soil erosion. Wetlands, on the other hand, serve as natural flood barriers, absorbing excess water and protecting coastal communities from the ravages of storms. These ecosystem services, provided by the intricate interactions of plants and animals, are essential for maintaining the health and resilience of our planet, with far-reaching impacts on human well-being and the sustainability of our own species.As we delve deeper into the mind map, we can also explore thecomplex relationships between plants, animals, and the abiotic components of the environment, such as soil, water, and atmospheric conditions. These non-living elements, in turn, influence the distribution, abundance, and adaptations of both plant and animal species, creating a dynamic and ever-evolving tapestry of life.In the face of the pressing environmental challenges we currently face, such as habitat destruction, climate change, and the loss of biodiversity, understanding the interconnectedness of the plant and animal kingdoms becomes increasingly vital. By visualizing these relationships through a comprehensive mind map, we can better grasp the fragility and importance of maintaining the delicate balance of our ecosystems. This knowledge can inform our decision-making, guide our conservation efforts, and inspire us to take action in protecting the natural world that sustains us all.In conclusion, the mind map of the plant and animal kingdom reveals a captivating and intricate web of relationships, interdependencies, and symbiotic interactions. By exploring this visual representation, we can gain a deeper appreciation for the delicate equilibrium that underpins the vibrant tapestry of life on our planet. As stewards of the natural world, it is our responsibility to safeguard this precious balance, ensuring that the diverse and awe-inspiring forms of life that share our world continue to thrive for generations to come.。

城市过去和现在的变化英语作文小学

城市过去和现在的变化英语作文小学全文共5篇示例，供读者参考篇1My City: Then and NowHi there! My name is Jamie and I'm going to tell you all about how my city has changed over the years. It's really fascinating stuff, so listen up!I live in a big, bustling city called Metropolitan City. It has tall skyscrapers, tons of people, and lots of cool things to see and do. But it didn't always look like this believe it or not!My grandparents have told me so many stories about what the city was like when they were kids. Back then, in the 1960s, Metropolitan City was much smaller. Instead of massive office buildings, there were just a few small shops and stores downtown. The sidewalks were made of cracked concrete instead of the smooth bricks we have now.One big difference is that there were way more parks and open green spaces scattered all around the city limits. My grandma remembers spending her summers running through wide open fields playing chase with her friends. Can you imaginethat? Nowadays those fields are all covered with houses, malls, and other buildings. We only have a few tiny parks left for the kids to play in.Transport looked super different too! Instead of having a subway system like we do today, people mostly just walked or rode bikes to get around town. Cars were still pretty new, so not too many families owned one. My grandpa says the streets were much quieter without all the traffic we have now. He also said the air was fresher and you could actually see the stars at night because there wasn't as much light pollution.Speaking of pollution, my grandparents said the rivers and streams around town used to be completely clean and crystal clear. You could drink right from them! People would go swimming, fishing, and have picnics right by the riverbanks. How crazy is that? Nowadays those same rivers are dirty and polluted from waste dumped into them by factories. No one would ever dream of swimming in that nasty water!The types of jobs people had were also really different back then compared to today. Most people living in Metropolitan City either worked on farms right outside of town or at the local factories and warehouses. There weren't many big office buildings or tech companies like we have these days. Mygrandpa actually worked at a huge automobile factory for his whole career until he retired.One more big change is how many more people and cultures live in Metropolitan City now versus the past. When my grandparents were young, the city was much more uniform in terms of the backgrounds people came from. But today, we have residents from all around the world who have brought their amazing customs, food, art, and more! I love how diverse and vibrant our city has become.With all these people coming in over the decades, the city has had to rapidly build more housing, shops, schools, and other infrastructure to keep up with the growth. That's why you'll see construction sites all over the place here working on new skyscrapers, roads, and subway lines. My dad's friend is actually an architect and he's gotten to design a couple of those new tall buildings downtown which is so awesome.Metropolitan City has sprouted up like bamboo over the past 50 years or so. It's wild to think about how much things have transformed in that short period of time! From a small, quiet town to a booming international metropolis with millions of people. Some things have been lost in the process for sure, likethe open green spaces my grandparents enjoyed. But I think a lot of the changes have been for the better too.We might have more traffic, pollution, and fewer parks, but we also have incredible new opportunities that simply didn't exist back in my grandparents' day. People can easily connect with cultures from across the globe, land high-paying jobs at innovative companies, and experience huge events like concerts or pro sports games whenever they want. The city's public transit has also made it super easy and convenient for everyone to get around without needing a car.Personally, I'm really glad I grew up in this modern era of Metropolitan City rather than the old days my grandparents keep telling me about. Sure, it was probably more peaceful and cleaner back then. But it also seems like it was kind of boring if I'm being honest! I'll take the bright lights and energy of the city today any day over those quiet open fields from long ago. Although maybe a couple more parks around town wouldn't hurt...Anyway, that's my take on how Metropolitan City has evolved over the past half century or so. Our city has come a incredibly long way and transformed itself into a cutting-edge urban center for business, culture, and innovation. It makes mereally excited to think about what other amazing changes could be in store for the future! Who knows what mind-blowing technological wonders or architectural marvels could reshape the city's skyline next. One thing's for sure though - Metropolitan City in 2070 will probably look unrecognizable compared to how it appears today. I can't wait to see it!篇2The City: Then and NowWhen my grandparents were kids, cities looked really different than they do today. Things have changed a lot over the years! Let me tell you about how cities used to be and how they are now.Back in the old days, most cities were much smaller. There were way fewer people living in them. My grandpa says that when he was little, his city only had about 50,000 people. Can you imagine? Today, there are millions of people in big cities like New York and Tokyo!Cities used to be built around factories, mills, and other places where people worked. Homes and shops would be clustered near the workplaces so people could walk to their jobs.Nowadays, many people drive or take trains from farther away suburbs into the city for work.Speaking of cars, there were not nearly as many vehicles on the roads years ago. Horse-drawn carriages and streetcars were much more common than automobiles. The streets were narrower and there was a lot less traffic. My grandma says you could play kickball right in the middle of the street when she was a girl! I definitely wouldn't want to do that today with all the cars zooming by.The skylines of old cities looked really different too. Back then, most buildings were pretty short - just a few stories tall. This was before steel and concrete were used to build skyscrapers. The tallest buildings in downtown areas were probably churches with their tall steeples. Today's cities are full of huge towers that stretch way up into the sky like giants!Air pollution was definitely worse in cities long ago because of all the smokestacks from factories. My grandparents say the sky always looked kind of hazy from the smog. Things like cars, heating systems, and manufacturing have gotten a lot cleaner over time. The air is fresher now, which is much healthier for everyone.Of course, stores and restaurants have changed a ton too. A long time ago, there were no big supermarkets or food chains. People shopped at small mom-and-pop grocery stores and markets right in their neighborhoods. For entertainment, families might go to vaudeville shows or nickelodeon movie theaters instead of big multiplexes we have now.Another big difference is how cities used to have more parks, gardens, and open spaces mixed in with the buildings and houses. As cities grew bigger, a lot of that green space got replaced by more construction. We are trying to add some green back into cities today by building rooftop gardens, planting trees along streets, and making new parks.Technology has transformed cities in so many ways too. When my grandparents were kids, things like computers, internet, cell phones, and digital screens didn't even exist! Cities ran on paper, payphones, and broadcast television. Nowadays, we are surrounded by computers and smartphones that connect everyone.Buildings have gotten much more modern too, with cool glass skyscrapers, movable skybridges, fancy lighting systems and so much more. Some cities are even experimenting withbuildings made out of wood or recycled materials instead of concrete and steel. How crazy is that?As you can see, cities have gone through an incredible transformation over the decades. From horse carriages toself-driving cars, from mom-and-pop stores to megamalls, from smokestacks to green skyscrapers - the old urban life of the past looks totally unrecognizable compared to cities today.And you know what? Cities will probably change even more by the time we are grandparents! Who knows what wild advancements and crazy technologies will remake the cities of the future? Flying cars zooming between neon skyscrapers? Houses that can walk around on mechanical legs? Holiday beach resorts on the moon? Anything seems possible!No matter how cities evolve, one thing is for sure - the place we call home will keep changing and changing and changing again. Cities are always in motion, just like the people who live in them. And that's what makes them so exciting!篇3The City Then and NowWow, cities sure have changed a lot from when my parents and grandparents were kids! My hometown looks totallydifferent now compared to old pictures. Let me tell you all about how cities have transformed over the years.Back in the day, cities were much smaller and didn't have nearly as many people living in them. My grandpa says when he was a boy, our city only had a couple thousand residents. Can you believe that? Nowadays, there are over a million people crammed into the same area! Cities used to be sleepy little towns with just a few streets and shops. But as more and more people moved in to find jobs, the cities got bigger and bigger.The buildings have changed a ton too. In the old days, most buildings were only a couple stories tall - cute little houses, shops, and churches made of brick or wood. But today's city skylines are filled with huge skyscrapers made of steel and glass! Some of them are over 100 floors high! My dad says the first skyscraper in our city was only 20 stories when it was built in the 1950s, and everyone thought it was enormous back then. But now it looks tiny compared to the monolithic towers surrounding it. Cities used to feel cozy, but now they seem almost overpowering with all the massive high-rise apartments and office buildings looming overhead.Transportation is another big difference. When my grandparents were young, there were way fewer cars around.Most people just walked wherever they needed to go in the city since everything was compact and nearby. Or if they needed to go farther, they took streetcars or buses. But today, driving is pretty much mandatory for city living unless you want to spend forever on public transport or walking everywhere. The streets are always clogged with traffic and cars honking impatiently. My grandma says she misses being able to cross the street safely without having to dodge speeding vehicles! To help control the traffic madness, cities nowadays have an endless maze of highways, tunnels, bridges and intersections. My head spins just thinking about navigating that road jungle.Cities have also lost a lot of their green spaces over the decades as they added more buildings, roads and parking lots. My grandparents reminisce about the beautiful parks with ponds, gardens and forest groves that used to be sprinkled throughout the city. You could walk outside and be surrounding by nature within a couple blocks. But little by little, those idyllic parks were paved over and replaced by concrete. There are still some decent parks left today, but most of them are on the city outskirts faraway from downtown areas. In the center, the only vegetation you tend to see is some scraggly trees and bushes crammed along the sidewalks. It makes me sad that cities sacrificed so much natural beauty as they grew.Speaking of nature, cities nowadays tend to be much worse for the environment too. With all the exhaust from millions of cars, along with pollution from factories and plants, the air quality is just terrible in big cities. My parents complain about the smog hanging over the skyline on hot days. And don't even get me started on litter! Candy wrappers, bottles, cigarette butts, you name it - you can find it strewn across gutters, vacant lots and storm drains all around the city. People were probably neater back in the day when cities were cleaner.It hasn't been all negative changes though! Cities today offer soooo many more opportunities, entertainment and public services compared to the old days. For jobs alone, my parents say cities used to have just basic stores, factories and offices. But now, cities have all kinds of companies, startups, and careers in industries like tech, finance, media, healthcare, you name it. Cities have morphed into true centers of business and innovation that pull in talented people from across the globe. There is also way more stuff to do for fun - amazing restaurants, museums, concerts, pro sports, the list goes on. Cities today are buzzing with arts, culture and nightlife you couldn't find in the sleepy towns of the past. And don't forget all the new parks, schools, libraries, and other public facilities cities have added to serve their booming populations.So while I do get nostalgic for the simpler, greener cities of the past based on my grandparents' tales, I also really appreciate all the perks and opportunities that come with living in a modern, thriving city. It gives me the best of both worlds - a fast-paced, exciting environment at the forefront of business and culture, but still with some parks and public spaces to enjoy nature. I just hope cities keep getting better about protecting the environment as they continue growing! After all, a city is no fun if the air is too polluted to breathe. Maybe urban planners can focus on finding the perfect balance between progress and nature preservation.Those are just my thoughts on how cities have evolved based on my family's stories and experiences. From tiny villages to massive concrete jungles, it's crazy to imagine just how dramatically cities have transformed over the past century or so. I can't even picture what mind-blowing changes cities will go through over my lifetime! Maybe we'll have flying cars zipping between neon skytowers and suspended parks by the time I'm a grownup. One can only dream...Or will that be reality? Only time will tell! I just hope cities keep getting better and better for each new generation to come.篇4My City: Then and NowWow, have things changed in my city over the years! When my grandparents were little kids, everything looked so different. Back then, there were hardly any tall buildings around. Most of the houses and shops were just one or two stories high. Can you imagine that? Nowadays, it seems like everywhere you look there are skyscrapers and huge apartment complexes towering up into the sky. The city skyline has totally transformed!In the old days, there weren't nearly as many cars and buses on the roads either. My grandpa says when he was a boy, you could play games like hopscotch and kickball right out in the street because there were so few vehicles around. Crazy, right? I definitely can't imagine doing that today with how busy and crazy the traffic is. Cars whizzing by, horns honking, buses rumbling down the street. It's a totally different world now.Speaking of transportation, did you know that a long, long time ago there weren't even any subways or trains in the city? That's right, no underground tunnels with rail lines to get around quickly. People had to walk everywhere they needed to go or ride horses and carriages. How slow and boring! I'm really glad we have the subways now so I can zip around wherever I need to be.The city used to be much quieter and less crowded too, according to my grandparents. There was a lot more open space with parks, gardens, and farms right within the city limits. These days, it seems like every last bit of land has buildings and roads crammed onto it. My grandma says you could actually see stars twinkling in the night sky back then because there wasn't as much light pollution. Pretty neat, huh? Too bad we can't see that anymore.Even the stores and restaurants were totally different back in my grandparents' day. There were no huge shopping malls or fast food chains like McDonald's and Burger King. Most of the shops were small mom-and-pop places owned by families. The grocery stores were tiny compared to the massive supermarkets we have now. And there definitely weren't any big movie theater multiplexes with 20 screens! Just small single-screen theaters. Doesn't that seem weird?One other major difference is how few parks and green spaces there used to be compared to today. My city has made a huge effort to preserve natural areas and create new parks with walking trails, playgrounds, duck ponds, and flowers over the past few decades. I'm really glad about that because I love goingto the park and riding my bike on the trails. It's a nice break from the hustle and bustle of the city.Of course, technology sure has changed a ton too! Computers, smartphones, the internet...my grandparents didn't have any of that crazy stuff when they were kids. No way to look things up instantly online or play video games. They had to entertainthemselves by playing outside or with simple toys and books. While I do like my electronics, I can see how life was maybe a bit simpler and less overwhelming back then without being plugged in constantly.So in a nutshell, my city has gone through a major transformation from a quieter, greener place to abusy, towering modern metropolis packed with people, cars, and technology. Some of the changes have been for the better and some worse. But one thing's for sure - it's evolved big time over the decades! I wonder what things will be like here when I'm a grandparent telling wild stories about "the old days?" Only time will tell!篇5Here's an essay about the changes in cities over time, written in English with a tone suitable for elementary school students, around 2000 words long:The City: Then and NowHave you ever wondered what your city looked like a long time ago? Cities change a lot over the years, and the place you live in today is probably very different from how it was in the past. Let me tell you about some of the cool changes that have happened in cities!A long time ago, most cities were much smaller than they are now. There were way fewer people living in them. Instead of tall skyscrapers and apartment buildings, there were mainly small houses and little shops. The streets were narrow, and there were no cars or buses. People got around by walking or riding horses and carriages.Back then, cities didn't have all the modern things we have today. There were no cell phones, computers, or internet. No one had televisions or video games either. Kids played with simple toys like dolls, spinning tops, and balls. They would run around outside and play games like hopscotch and jump rope.Life was very different without all the technology we're used to. There were no big grocery stores, so people had to buy food from little markets or grow their own fruits and vegetables. They didn't have refrigerators, so they had to go shopping for fresh food every day.Cities also looked quite different long ago. There were no tall buildings blocking the view of the sky. At night, the streets were dark because there were no bright lights everywhere like we have today. Instead of electric lights, people used candles, oil lamps, and gas lamps to see at night.One of the biggest changes in cities over time is transportation. Horse-drawn carriages were eventually replaced by cars, buses, and trains. Traveling long distances became much easier and faster. Imagine having to ride in a bumpy carriage for days just to get to the next town!As cities grew bigger, they started building more parks and green spaces for people to enjoy nature. Many cities used to be crowded and dirty, but now they have beautiful gardens, playgrounds, and walking trails. Having nice parks helps make cities cleaner and healthier places to live.Another major change is how cities get their power and energy. A long time ago, there was no electricity at all. Then cities started using coal and oil to power factories and homes. These days, many cities are switching to cleaner energy sources like solar, wind, and water power to protect the environment.Speaking of the environment, cities today are working hard to reduce pollution and waste. We now have recycling programsand ways to turn trash into energy. People are driving electric cars and using public transportation more to cut down on pollution from gas-powered vehicles.As you can see, cities have gone through so many exciting changes over the years. From horse carriages to self-driving cars, from candles to LED lights, from little markets to giant shopping malls – the city you live in has transformed in amazing ways!Things will keep changing and evolving as people come up with new ideas and inventions. Who knows what cities will be like a hundred years from now? Flying cars? Towering buildings as tall as mountains? Robot assistants to help with chores? Only time will tell what the city of the future will look like!。

我们应该如何拯救树英语作文初一

我们应该如何拯救树英语作文初一Trees are the lungs of our planet, providing us with oxygen and absorbing carbon dioxide. They are home to millions of species and provide us with food, shelter, and medicine. Despite their immense value, trees are being cut down at an alarming rate, leading to a decline in biodiversity, soil erosion, climate change, and more. As young students, it's our responsibility to take action and save our trees. Here are some ways we can contribute to the effort:**1. Plant More Trees**One of the simplest and most effective ways to save our trees is to plant more of them. We can start by planting a tree in our gardens or community spaces. We can also participate in tree-planting campaigns organized by schools or NGOs. Every tree we plant helps absorb carbon dioxide, releases oxygen, and provides a home for wildlife.**2. Reduce Our Use of Paper**Paper is made from trees, so reducing our use of paper helps save trees. We can start by using both sides of thepaper before throwing it away. We can also recycle paperand use digital means like emails and online documents instead of printing out everything.**3. Conserve Water**Trees need water to grow, so conserving water helpsthem thrive. We can make sure to water our plants and trees regularly, but not excessively. We can also fix leaky faucets and pipes to prevent water waste.**4. Spread Awareness**Spreading awareness about the importance of trees and the need to save them is crucial. We can talk to our family, friends, and neighbors about the importance of trees and encourage them to take action. We can also share posts and videos on social media to reach a wider audience.**5. Support Policies that Protect Trees**Supporting policies that protect trees and forests is another way we can contribute. We can write to our local government officials and demand stronger laws to protect trees. We can also participate in rallies and protests to show our support for tree protection.In conclusion, saving our trees is crucial for thehealth of our planet and future generations. As students,we have the power to make a difference. By planting trees, reducing our use of paper, conserving water, spreading awareness, and supporting policies that protect trees, we can help save our planet and ensure a sustainable futurefor all.**拯救我们的树木：行动的呼唤**树木是我们星球的肺，为我们提供氧气并吸收二氧化碳。

现在获取信息的方式英语作文

现在获取信息的方式英语作文In today's technology-driven world, there are various ways to obtain information. Whether it's through traditional means such as books and newspapers, or modern sources like the internet and social media, the abundance of information at our fingertips has profoundly shaped the way we learn and stay informed. With just a few clicks, we can access a wealth of knowledge on virtually any topic, making the process of gathering information easier and more convenient than ever before.在当今由技术驱动的世界里，获取信息的途径多种多样。

无论是通过传统的途径，如书籍和报纸，还是现代的来源，比如互联网和社交媒体，我们的指尖都可以得到丰富的信息，深刻地塑造了我们学习和获取信息的方式。

只需点击几下，我们就可以获得几乎任何话题的大量知识，使信息收集的过程比以往任何时候都更容易、更方便。

While the ease of access to information is undoubtedly a positive aspect of modern technology, it also comes with its drawbacks. With the sheer volume of information available online, it can be challenging to discern between reliable sources and misinformation.This influx of information can lead to information overload, where individuals may feel overwhelmed and struggle to process and digest the massive amounts of data being presented to them.尽管信息获取的便捷性无疑是现代技术的一个积极方面，但它也伴随着其缺点。

新教材高中英语UNIT5RevealingnaturePart4Writing提升训练含解析

Part 4 Writing应用文写作写作题目假设你是李华,英语老师让你观察某种植物的生长过程。

请根据你所拍摄的图片写一篇观察日记,记述蒜苗的生长过程,以便在英语课上跟大家分享。

内容包括:1.种植方式;2.生长环境;3.生长变化。

注意:1.词数100左右;2.可适当增加细节,以使行文连贯。

参考词汇: garlic clove蒜瓣;tender shoot嫩芽;garlic sprout 蒜苗思路点拨主题观察植物生长体裁应用文以第一、三人称时态以一般现在时为主人称为主第一部分:播种方式;布局第二部分:生长过程;第三部分:生长结果。

遣词造句Ⅰ.用本单元所学单词或短语填空1. 肩并肩地,并排地2. 出来3. n.根4. n.厘米答案 1.side by side 2.get out of 3.root 4.centimetreⅡ.本单元语块、语法运用1.完成句子(1)我小心地把蒜头分成蒜瓣,并排地种在一个圆形塑料碗里,尖头朝上。

I carefully divide the garlic bulbs into cloves andin a round plastic bowl, and the pointed ends .(2)随着大蒜的生长,根长得越来越长。

With the garlic , the roots grow .(3)根看起来像爷爷的白胡子。

The roots the white beard of Grandpa.(4)蒜苗一天天长得越来越高,已经长到20厘米左右了。

The garlic sprouts are growing higher and higher , and they about 20 centimetres.答案(1) plant them side by side; face up(2) growing;longer and longer(3) look like(4) day by day; have grown to2.句式升级(5)用with的复合结构改写句(1)(6)把句(2)和句(3)合并成一个含有定语从句的复合句答案(5) I carefully divide the garlic bulbs into cloves and plant them side by side in a round plastic bowl, with the pointed ends facing up.(6) With the garlic growing, the roots grow longer and longer, which look like the white beard of Grandpa.连句成篇参考范文January 8I carefully divide the garlic bulbs into cloves and plant them side by side in a round plastic bowl, with the pointed ends facing up. Then I pour enough water into the bowl and put it in a sunny place. Every day,I water them on time.January 16Many light green tender shoots are getting out of the cloves. With the garlic growing, the roots grow longer and longer, which look like the white beard of Grandpa.January 24The garlic sprouts are growing higher and higher day by day, and they have grown to about 20 centimetres. All of them look very beautiful, and are not less beautiful than daffodils.写作积累1.Let me tell you about how to plant a tree.让我告诉你如何种树。

九年级英语植物进化历程单选题50题

九年级英语植物进化历程单选题50题1. In the early stage of plant evolution, the first plants were mostly _.A. tall trees with complex root systemsB. small and simple organisms without true rootsC. large plants with broad leavesD. flowering plants答案：B。

解析：在植物进化的早期阶段，最早的植物是比较简单微小的，并且没有真正的根。

选项A中提到的有着复杂根系的高大树木是植物进化到较晚阶段才出现的特征，不符合早期植物的特点，所以A错误。

选项C中的有着阔叶的大型植物也是在植物进化后期才出现的，早期植物并非如此，C错误。

选项D开花植物是植物进化历程中较晚出现的类型，早期植物不会是开花植物，D错误。

2. The early plants in the process of evolution were likely to live _.A. in dry desertsB. in deep oceansC. in moist and shady placesD. on high mountains答案：C。

解析：早期植物在进化过程中，它们的结构和功能还比较简单，更适合在潮湿和阴暗的地方生存。

干燥的沙漠（选项A）环境较为恶劣，早期植物难以适应这样的干旱环境。

深海洋（（选项B）虽然也有水环境，但早期植物主要是从陆地的潮湿环境开始发展的，而不是深海洋环境。

高山（（选项D）的环境条件对早期简单结构的植物来说过于复杂和恶劣，不适合早期植物生存。

3. What was the main form of the early plants' structure?A. They had well - developed vascular systems.B. They were just like green threads or mats.C. They had thick trunks and long branches.D. They were spherical in shape.答案：B。

对于选物理类还是历史类的建议英语作文

对于选物理类还是历史类的建议英语作文全文共3篇示例，供读者参考篇1Should I Major in Physics or History?As a high school student, one of the biggest decisions I have to make is what to study in college. Two subjects I'm really passionate about are physics and history, but they are worlds apart. Physics deals with the fundamental laws of the universe through mathematics, experiments, and analytical thinking. History, on the other hand, is a descriptive field that seeks to understand the past through interpreting artifacts, documents, and other sources. Trying to decide between such vastly different disciplines is an agonizing choice.On one level, the appeal of physics is strong. The theories and laws like gravity, electromagnetism, and quantum mechanics elegantly explain the workings of the entire cosmos, from the subatomic realm to galaxies billions of light years away. There's something profound about comprehending the mathematical rules that govern reality itself. Physicists are constantly probing the boundaries of human knowledge through experiments atplaces like the Large Hadron Collider. Just think about the magnitude of their achievements - physicists mapped the evolution of the entire universe from the Big Bang to the present! They've shattered our antiquated notions of space, time, energy, and matter. And cutting-edge fields like quantum computing could revolutionize technology beyond our wildest dreams.At the same time, physics is infamous for being one of the most mentally demanding subjects. The higher-level math like calculus, differential equations, and linear algebra is incredibly abstract and brain-bending. Physics relies heavily on quantitative skills and strong mathematical reasoning abilities. Not everyone can handle deriving and manipulating complex equations. It's an elite field where you have to be among the top students because the competition is so intense. Even if you love physics, the workload could potentially crush your soul or cause you to burn out. Some prodigies seem to breathe this stuff effortlessly,butI'm not sure if I have that level of raw intellect.Then there's history, which has its own powerful allure. While physics describes the immutable laws of nature, history aims to make sense of our unbelievably rich human experience on this planet. From piecing together prehistoric societies to chronicling the rise and fall of great empires, studying history providesinvaluable context about who we are and how we got to this point. History is endlessly fascinating because it's the story of ourselves - our values, struggles, conflicts, beliefs, accomplishments, and blunders. Understanding different cultures, customs, and ideologies can promote cross-cultural understanding in an increasingly globalized world.Additionally, history trains your mind to analyze ambiguous information, think critically, and construct well-reasoned arguments based on evidence - skills invaluable for any career. You have to weigh multiple perspectives, evaluate reliability of sources, and draw insights from fragmentary data. Instead of absolute right and wrong answers, history encourages formulating logical hypotheses while allowing for alternative interpretations. This intellectual flexibility and open-mindedness can serve you well in any field, from law and business to public policy.On the flip side, some view history as just a collection of dates, names, and inert facts to memorize. To the uninitiated, it may seem less applicable to employment than a hard science like physics. There's a stereotype that history only leads to career paths like teaching or working at museums. Of course, that's an oversimplification - historians can utilize their research, writing,and analytical talents in government, law, business, journalism, and so many other sectors. But the misconception about limited job prospects could dissuade some students from pursuing history at higher levels. There's also the reality that top history programs and jobs are extremely competitive, just like physics.In the end, both physics and history have their merits and drawbacks. Physics represents the pinnacle of systematic human understanding about the material world - complex, quantitative, elite. History reflects our endless quest to comprehend the forces that shape the human experience - descriptive, literary, cultural. While drastically different, they each appeal to the core of what drives intellectual curiosity and the search for knowledge.For me personally, my passion for history slightly outweighs my love of physics - at least at this stage. I find myself constantly intrigued by learning about pivotal events, trends, and figures across different eras. From the ancient civilizations to the modern age, I want to obtain a grand perspective on the human journey. To quote the great historian David McCullough, "History is a source of pleasure, of fresh insights, of a kind of powerhouse of inspiration." I can vividly imagine myself poring over primary sources, crafting narratives from the fragments of the past. Whilephysics will always fascinate me, its ultra-demanding nature gives me pause about pursuing it as a career.Still, I would never want to abandon physics entirely. The conceptual elegance, from Newtonian mechanics to quantum theory to relativity, is something to behold. Even as a history student, continuing physics education could be immensely rewarding. Many top universities allow copious flexibility for double majors or pursuing physics as a minor or a second degree. Ideally, I'd aim to blend both fields - using the precise quantitative tools of physics while applying them to humanities questions. Techniques like data analysis, modeling, and statistics could augment more traditional historical methodologies. An inter disciplinary combination could facilitate insights that neither field alone could achieve.Ultimately, there's no objectively "right" choice - it depends on one's individual aptitudes, interests, and goals. My advice to other students in this difficult position? Don't feel pressured to prematurely commit to one path. Immerse yourself in both disciplines in the early years at university before making a final determination. Take a diverse range of classes to help figure out where your true intellectual passion lies. And remember, education doesn't stop at the bachelor's level - you can alwayspursue another field or specialization later. The most important decision criterion should be to study what inspires and fulfills you. After all, the greatest scientists and scholars were all united by an unbridled curiosity to explore the mysteries around them. Whichever direction you choose, stay true to that spirit of passionate inquiry.篇2Should I Major in Physics or History? My Advice as a College StudentAs a college student, one of the biggest decisions I've had to make is what to major in. There are so many fascinating subjects to choose from, each opening the door to different career paths and ways of looking at the world. For me, the choice came down to two wildly different fields: physics and history. On one hand, physics is the fundamental study of the laws that govern the natural world. On the other, history delves into the rich tapestry of human civilization across time. Both subjects captivated me for different reasons when I was in high school, so how was I to decide which to pursue as a college major and potential career?After much reflection, I ultimately chose to major in physics. However, that decision was not an easy one, nor do I think it wasnecessarily the "right" choice. History is a remarkable field that continues to be a deep passion of mine alongside physics. I hope that by weighing the pros and cons of each discipline, I can provide some useful advice to other students trying to make this difficult decision.The Case for Majoring in HistoryTo begin with the appeal of history, there is something profound about studying how human societies have evolved, overcome challenges, and shaped the modern world we live in today. Historians get to be detectives, piecing together the story of the past through artifacts, documents, and other primary sources. Every era from ancient civilizations to the modern age has a rich history to uncover and analyze.Studying history means constantly encountering new perspectives and worldviews. We can learn so much from how past cultures organized their societies, expressed themselves through art and literature, or tackled issues like war, justice, and technological progress. History is one of the most human fields there is, shining a light on the driving forces, ideologies, and personalities that have gotten us to where we are today.For students with a love of stories, cultures, writing, and exploration of the human experience, history could be anincredibly fulfilling path. There are also diverse career options for history majors, including roles in museums, archives, teaching, politics, journalism, and more. Developing strong research, writing, and critical thinking abilities makes history an excellent liberal arts major.Additionally, being a history buff allows you to be part of an ongoing conversation spanning centuries. You can engage with classic historians and debate their perspectives using modern evidence and understanding. There's a vibrant community of history enthusiasts constantly reexamining the past and fitting more puzzle pieces together.The Case for Majoring in PhysicsDespite the incredible appeal of history, my decision ultimately came down on the side of physics. While history illuminates the human experience, physics describes the fundamental laws that govern reality itself. It tackles the deepest questions about the nature of matter, energy, space, and time. Physicists get to study everything from the tiniest subatomic particles to the movement of galaxies and even the origins of the universe itself.To me, there is an unparalleled beauty and elegance to the mathematical laws physicists have uncovered about how thephysical world works. Yes, solving equations can be challenging. But there is something wondrous about recognizing the same principles in action across all scales, from the quantum realm to the cosmic expanse of spacetime. Physics has incredible explanatory power and allows us to make predictions with astonishing precision.Majoring in physics means joining a tradition of brilliant thinkers who have radically reshaped our understanding of reality, from Newton's laws of motion to Maxwell's conception of electromagnetism to Einstein's theories of relativity. The cutting edge of physics today deals with mind-bending realms like quantum mechanics, black holes, dark matter and dark energy. There are still so many deep mysteries about the fundamental workings of the universe remaining to be uncovered.From a pragmatic perspective, a physics degree can lead to diverse career opportunities in academia, research, engineering, technology, aerospace, and many other fields. Physicists are elite problem-solvers with expertise in mathematics, coding, data analysis, and complex theoretical modeling. These skills are extremely valued across many industries. A background in physics can set you up for an intellectually rigorous and potentially lucrative STEM career.However, even if you don't end up directly in a physics vocation, studying the methods of physics provides excellent training in quantitative reasoning, logical thinking, and tackling complex systems. It's a challenging path that builds important real-world skills.My Decision and AdviceIn the end, my love for unraveling the mysteries of the natural world edged out my deep fascination with human history and civilizations. The precise, deterministic laws of physics had a unique intellectual allure that made the decision for me. But that is simply my personal path - there is no objectively "correct" choice between such different but equally rich fields.History and physics are radically different lenses for understanding our world. If exploring the driving forces, cultural evolution, and lived experiences of human societies over time is your greatest passion, then history may be the path for you. The qualities of a great historian - knack for storytelling, skilled writing, insatiable curiosity, synthesizing diverse evidence - could lead you to an immensely meaningful career.On the other hand, if you are most enthralled by the fundamental workings of the natural world and the quest to uncover its deepest laws through rigorous mathematics,experimentation, and theoretical modeling, then physics may be your calling. The skills learned in physics open doors to many technical and analytical career paths.My advice is this: don't decide based solely on perception of career prospects or earning potential, as both majors have diverse options. Choose the path that most deeply inspires your curiosity and aligns with your core passions and interests. Both physics and history are incredibly enriching fields that shape how we understand ourselves and our universe. You can't go wrong with either choice - the most important thing is that you dive in and immerse yourself. Follow what you love and you'll find a way to forge a rewarding path.Weigh the pros and cons carefully, and don't be afraid to keep exploring and take a few classes in each before deciding. I know I'll never lose my respect and enthusiasm for history even as I pursue a career more focused on physics. The two disciplines can complement each other beautifully. At their core, both strive to illuminate truth through intellectual inquiry, rigor, and dedication. The quest for knowledge unites the sciences and humanities.篇3To Be Or Not To Be...A Physics or History Major?That is the question that has been weighing heavily on my mind as I approach the end of my high school years and look ahead to college. Physics and history are two vastly different fields of study, each with their own unique appeals and challenges. As someone with a keen interest in both the natural world and the human story, I find myself torn between these two paths.On one hand, physics delves into the fundamental laws that govern the universe, offering a profound understanding of how everything works, from the smallest subatomic particles to the largest celestial bodies. There is an undeniable elegance and beauty in the mathematical precision and empirical rigor that define this discipline. To study physics is to unlock the secrets of creation itself, to peer into realms that have baffled humanity for millennia.Yet, history offers a different kind of magic – the magic of understanding the rich tapestry of human experience across time and cultures. To study history is to embark on a grand odyssey through the triumphs, tragedies, and turning points that have shaped our world. It is to gain insight into the complex interplayof ideas, events, and personalities that have propelled human civilization forward, for better or worse.As I weigh these two paths, I find myself drawn to both the intellectual rigor and potential for groundbreaking discoveries inherent in physics, as well as the profound human insights and cultural awareness that come with the study of history. Each field promises a unique and transformative educational journey, one that will shape not only my academic pursuits but also my worldview and approach to life itself.Perhaps the most significant consideration in choosing between these two disciplines is one's natural inclinations and intellectual curiosities. Are you someone who finds solace in the precision and predictability of mathematical models and scientific laws? Or are you more captivated by the rich tapestry of human stories, the nuances of cultural expression, and theever-shifting tides of social and political change?For those with a bent towards the analytical and a deep fascination with the fundamental building blocks of reality, physics may be the siren call that cannot be ignored. To unravel the mysteries of quantum mechanics, delve into themind-bending realms of relativity, or even contribute to theongoing quest for a unified theory of everything – these are the tantalizing prospects that await the aspiring physicist.On the other hand, those drawn to the complexities of human experience, the intricate web of causality that shapes historical events, and the enduring power of cultural narratives may find their true calling in the study of history. To understand the rise and fall of civilizations, the clashes and syntheses of ideologies, and the enduring human struggles for freedom, justice, and self-determination – these are the profound rewards that beckon the historian.Ultimately, the choice between physics and history is a deeply personal one, shaped by our individual passions, strengths, and intellectual curiosities. For some, the allure of unlocking the secrets of the cosmos may prove irresistible, while others may find their true calling in unraveling the rich tapestry of human experience.Yet, perhaps the greatest wisdom lies in recognizing that these two disciplines, though divergent in their subject matter, share a common foundation in the pursuit of knowledge, the quest for understanding, and the unquenchable human thirst for intellectual exploration. Whether one chooses to study the laws of nature or the chronicles of human civilization, the true rewardlies in the journey itself – a journey of discovery, wonder, and insatiable curiosity.As for me, I find myself drawn to both paths, each beckoning with its own siren song of intellectual fulfillment. Perhaps the answer lies not in choosing one over the other, but in embracing the richness of both perspectives, allowing the insights of physics and history to intertwine and inform my understanding of the world around me.For is it not in the synthesis of these two realms – the natural and the human, the universal and the particular – that we can truly begin to grasp the full depth and complexity of our existence? To study the fundamental laws that govern the cosmos while simultaneously exploring the cultural narratives and historical forces that have shaped our species is to embark on a transcendent intellectual odyssey, one that holds the promise of profound personal growth and understanding.So, as I stand at this crossroads, I find myself resolving not to choose between physics and history, but rather to embrace them both – to immerse myself in the eternal dance between the laws of nature and the unfolding human story. For it is in the harmonious synthesis of these two great pillars of knowledgethat we may find the keys to unlocking the deepest mysteries of our universe and our place within it.。

托福阅读真题第248篇ArchaeopteryxandFlight（答案文章最后）

托福阅读真题第248篇ArchaeopteryxandFlight（答案文章最后）Archaeopteryx and FlightParagraph 1: It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly—but it probably did, at least for short distances. We can make reasoned guesses about how it might have done so, but there is no conclusive evidence about flying in Archaeopteryx because while fossils can tell us about an animal’s physiology, the y cannot tell us about an animal's behavior. First, we should look at the methods that animals other than birds use to become airborne. Even though birds have the most astounding abilities of flight, they are not the only creatures to take to the air. Some existing species of frogs, snakes, lizards, and mammals launch themselves from a height and glide for considerable distances in the air. They do so by using skin flaps on the sides of their bodies or by extending broad, sail like limbs. The gliders of Australia are typical examples of this kind of flight. Some of the ancient reptiles living in the late Triassic period more than 200 million years ago used this method of flying. A fossil record of a flying reptile (a saurian) called Protoavis texensis has been dated to that time. That species could represent one of the first steps toward the evolution of birds, but many ancient reptiles had flaps of skin or long scale-like structures that they could have used for gliding or even more sustained flying.1. Th e word “conclusive” in the passage is closest in meaning toO possibleO convincingO survivingO favorable2. The word “extending” in the passage is closest in meaning toO developingO spreadingO usingO flapping3. According to paragraph 1, why have scientists looked for clues to Archaeopteryx flight by studying how other animals fly?O Complete Archaeopteryx fossils have not been found.O They discovered the remains of late Triassic reptiles that seemed to fly.O Archaeopteryx activity cannot be determined from its remains.O Archaeopteryx fossils are not detailed enough to make important aspects of its physiology clear.4. In paragraph 1, why does the author provide the information that Protoavis texensis existed in the late Triassic period?O To support the statement that some early reptiles used the gliding method of flyingO To identify an animal species that was related to ArchaeopteryxO To indicate a flying species that left more fossils than Archaeopteryx didO To demonstrate the importance of flight for early reptiles Paragraph 2: Archaeopteryx could have used its feathers to aid gliding after climbing up a high tree, using its finger claws, and then launching itself into the air. This is known as the trees-down hypothesis. Alternatively, it could have used its wings to obtain liftoff after running fast on the ground with its wings flapping. This is known as the ground-up, or cursorial, hypothesis. Archaeopteryx might, for example, have used running and flapping flight to catch insects. This hypothesis links wing use to feeding and takes into account the fact that Archaeopteryx had teeth and fed on meat, either exclusively or among other things. It might have used its feathers simply to provide air resistance (drag) when pouncing on prey. Pouncing might then have turned into swooping as feathers and flight muscles provided better liftoff. Evolving to be smaller in size would have been another factor essential for becoming airborne, but that occurred after the time of Archaeopteryx. In fact, it seems that Archaeopteryx was unable to become fully airborne after running and flapping flight because, given its construction, to provide sufficient energy for takeoff, it would have needed to run much faster than possible.5. According to the trees-down hypothesis described in paragraph 2, which of the following was true of Archaeopteryx flight?O Archaeopteryx launched itself in the air in order to begin its climb up a treeO Archaeopteryx used its feathers to help it climb up trees.O Archaeopteryx used its feathers to continue travel through the air.O Archaeopteryx used its finger claws to aid gliding6. According to paragraph 2, why is the ground-up hypothesis unlikely in the case of the Archaeopteryx?O It did not have a sufficient number of feathers to sustain itself in the air.O It could not have run fast enough to take off into the air.O Its meat-eating teeth suggest that its early flight was linked to hunting in trees.O It was too small to provide the liftoff essential for flight Paragraph 3: Another suggestion, no longer popular, is that Archaeopteryx used its winged forelimbs rather like fans to trap insects as it ran along the ground. Later wings evolved and were used in flying. This hypothesis is similar to the idea that feathers first evolved for insulation, in the sense that feathers are said to have first appeared for purposes other than flying. Another alternative is that feathers first evolved for performing the visual displays used in social communication and were only later used for flying. Modern birds use their feathers to communicate, with often spectacular visual displays. It is possible that the first feathered creatures (ancient birds and theropod dinosaurs) used their feathers in similar ways to communicate with other members of their species. Evidence that dinosaurs formed groups supports the idea that they may have communicated using vocalizations or visual displays.7. Why does the author provide the information in paragraph 3 that modern birds use their feathers to communicate?O To illustrate how flight has led birds to other types of behaviorO To support one possibility for an early use of Archaeopteryx feathersO To contrast the use of feathers by modern and ancient speciesO To show the extent of social behavior in various species8. Which of the following statements is supported by both hypotheses discussed in paragraph 3?O Archaeopteryx flight evolved as a way to capture prey more easily.O The physical characteristics necessary for flight originally evolved for other uses.O The original purposes for Archaeopteryx flight are no longer used by modern species.O The early methods of flight were unsuccessful for long periods of time.Paragraph 4: None of these hypotheses about the first uses of feathers can help us to decide whether Archaeopteryx was a ground-up or a trees-down flier. It is a matter of putting the many pieces of evidence together and coming up with the most plausible hypothesis, but there is no overwhelming evidence to determine whether Archaeopteryx glided down from above or flapped its way up from a running start on the ground. We can say, however, that only the trees-down hypothesis finds a good use for its hooked finger claws—used to climb up trees. Claws could, of course, be used in a number of different ways—some other ancient birds too large to fly had claws, which they must have used for purposes other than climbing.Paragraph 1: It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly—but it probably did, at least for short distances. We can make reasoned guesses about how it might have done so, but there is no conclusive evidence about flying in Archaeopteryx because while fossils can tell us about an animal’s phys iology, they cannot tell us about an animal's behavior. First, we should look at the methods that animals other than birds use to become airborne. Even though birds have the most astounding abilities of flight, they are not the only creatures to take to the air. Someexisting species of frogs, snakes, lizards, and mammals launch themselves from a height and glide for considerable distances in the air. They do so by using skin flaps on the sides of their bodies or by extending broad, sail like limbs. ■The g liders of Australia are typical examples of this kind of flight. ■Some of the ancient reptiles living in the late Triassic period more than 200 million years ago used this method of flying. A fossil record of a flying reptile (a saurian) called Protoavis texensis has been dated to that time. ■That species could represent one of the first steps toward the evolution of birds, but many ancient reptiles had flaps of skin or long scale-like structures that they could have used for gliding or even more sustained flying. ■9. Look at the four squares [■] that indicate where the following sentence could be added to the passageThe fossil record shows that these animals are not the first to employ it.Where would the sentence best fit? Click on a square [■] to add the sentence to the passage10. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Answer ChoicesO In the late Triassic period, several creatures developed the ability to fly, including Archaeopteryx, Protoavis texensis, and various early forms of frogs, snakes, and lizards.O By running along the ground and flapping its wings,Archaeopteryx may have been able to achieve low-level flight in order to catch prey.O Though feathers aid flight, Archaeopteryx may have originally evolved feathers for purposes unrelated to flight such as insulation or visual communication.O Archaeopteryx may have started to fly by climbing up trees and then using its feathers to glide down through the air.O Archaeopteryx may have developed flight by jumping repeatedly in the air in order to obtain prey in trees, using its feathers to slow its fall to the ground.O One key to Archaeopteryx flight is the hooked finger claw that was found in the fossil evidence, which makes both major hypotheses generally plausible.。

野性的呼唤英文读后感英文版

野性的呼唤英文读后感英文版野性的呼唤英文读后感英文版（精选11篇）《野性的呼唤》，又名《荒野的呼唤》（The Call of the Wild），美国著名作家杰克伦敦所著。

作品以一只狗的经历表现文明世界的狗在主人的逼迫下回到野蛮，写的是狗，也反映人的世界。

热望本已在，蓬勃脱尘埃；沉沉长眠后，野性重归来。

巴克原是米勒法官家的一只爱犬，经过了文明的教化，一直生活在美国南部加州一个温暖的山谷里。

后被卖到美国北部寒冷偏远、盛产黄金的阿拉斯加，成了一只拉雪橇的狗。

以下是小编为大家带来的野性的呼唤英文读后感英文版，希望大家喜欢。

野性的呼唤英文读后感英文版篇1“When the long winter nights come on and the wolves follow their meat into the lower valleys, he may be seen running at the head of the back through the pale moonlight or glimmering borealis, leaping gigantic above his followers, his great throat a bellow as he sings a song of the younger world, which is the song of the pack.”There was a script about the savage life in the frozen north of ice and snow. There were the unexplored north areas of America and the 19th-century Klondike Gold Rush which dragged men from the entire world into the hard wild to look for gold. There was a road where a gigantic dog like human fought his way to struggle in the wasteland. There was a civilized beast grew from mildness to wildness. And there came the call of the wild.The background and plotIn the 19th century, it was said that gold had been found in the Klondike area in Northern California of vast wilderness, so thousands of people rushed into this uncultivated ground to seekfor gold and fortune, which needed a large quantity of dogs to support for the transportation. There came up Buck story which we can’t define it as luckiness or unluckiness.Buck, a dog weighed one hundred and forty pounds, tall, strong, and heavy muscled, lived a cozy and comfortable life in a rich family of a Judge named Miller, but was soled by evil gardener to two dog dealers and was took to Alaska as a sled dog.Led by his second masters, two governmental couriers, he studied how to pull a sled and how to live in this cruel world where needed more cunning behavior and less fake moral and courtesy. For example, he learned to sleep in the snow hole to get warmness from the clod nights, and he learned to thief bacon and food from his masters and neighboring camps, as well as that, he learned how to fight effectively and efficiently with his antagonists and survive of the combat about the dominant leader with Spitz. In addition to those, he also went through the hardships in the toil on the ice layer, and he learned how to obtain the victory and stand on the wilderness which was beneficial to himself who can only fit the environment, but can’t defy the harness.After the arduous trace and trail, they finally reached the destination, and then, after a short break, dogs including Buck led by a Scotch half-breed man stepped again on the ice land with the Salt Water Mail. It was a hard trip and a monotonous life operating like machine that dogs must undertake the heave pulling and poor condition where they were tired and short of weight. Buck’ partner, Dave who had something wrong inside suffered most of all, but pride as he was, pulling the sled was his holy missionary job which can fulfill his life and must be doneuntil his death. However, the tough work was still continuous.Thirty days passes, by which time Buck and his mates found how really tired and weak they are until they arrived at the last town. They were in a wretched state, worn out and worn out, which was not the tiredness that came from a brief and excessive effort and can be recovered from some hours’ rest, but was the dead tiredness that came through the slow and prolonged strength drainage of months of toil and had to need a long vocation to evacuate. Nevertheless, only three days after they were bought by a family including a foolish woman, a callow and ignorant youngster, and a middle aged man with weak and watery eyes. Never mind of dog’s frazzle, the third masters t ried their best to lash out at them with whip, but Buck was not under very good command and not proud and interested of this career. Until they reached at the camp of Thornton, with the natural instinct and extreme weariness, Buck tolerated the whip from his so called masters and refused to go ahead which was his luckiness to meet his last master, Thornton.Without doubt, Thornton was a good master, full of wisdom, intelligence and love who can manage Buck’s life comfortably and in order. By the careful attendance form his new master, Buck was on his feet quickly and solidly. Filled with the loying love toward his master, Buck companied him, saved his life for several times and helped him win the gambling party. Then, they faced into the East on an unknown trail to achieve where men and dogs as good as themselves has failed, as the call from the wild became stronger and stronger which attracted Buck to leave the civilization to look for. The knife that cut out the bound of Buck between his masters was the mas ter’s deaths which left a void in the dog’s heart and a strengthened calling from the wild.Buck, a civilized dog, finally went back to wolves after thousands of generation by singing a song of the younger world, which is the song of the pack.Survive of the fittestThe Call of the Wild abounded in Darwinism which advocated the evolutionism and natural selection theory.In the process of having to leave the comfortable Miller’s house and adapt to the harsh primitive snowfield, Buck went through the changes from the mildness to wildness where he studied the law of club and fang and admitted the rule of failure without progress. “He had learned well the law of club and fang, and he never forewent an advantage or drew back from a foe he had started on the way t o death.” “He must master or be mastered,” “Kill or be killed, eat or be eaten, was the law; and this mandate, down out of the depths of time, he obeyed.”After analysis, we can find that related to the Darwinism, learning ability was an important factor of the victory of living of Buck. As a south dog living in the rich family and innocent environment, Buck was not wary of Manuel’s uncommon behavior, but situation has changed entirely after a period of barbaric life: he showed hostility to his all possible mates and took precaution of everything. As well as that, throwing away the moral standard and facing the death of starvation, Buck had an ability of thief. “This first theft marked Buck as fit to survive in the hostile Northland environment. It marked his adaptability, his capacity to adjust himself to changing conditions, the lack of which would have meat swift and terrible death.” In addition to those, his muscles became hard as iron, and he grew dumb to all ordinary pain, and he can successful take full use of all the elements no matter internal or external. That’s the progressionof Buck which can equip him with thick helmets from being hurt deeply and made him be the fittest.Not only did he learnt by experience, but instincts long dead became alive again. Maybe knowledge acquired by learning was Buck’s left hand, instincts his right. Good pedigree set up his first sense of a tall, strong and muscular potential king, while the instinct helped him to learn fast and save his life. “It was no task for him to learn to fight with cut and slash and the quick wolf snap.” “They came to him without effort or discovery, as though they had been his always.”Buck changed as his living environment changed. With the change of environment, Buck, compared to the previous southern family dog that was mild and gentle, acquired many abilities and skills. He tried his best to live by becoming cunning, cold-blood, and cruel which make him step forward on the road of corpse and blood. Survive of the fittest which is demonstrated by adaptation to the environment and wielding the law to protect himself and attack on others made him roared on the top of the food chain and return to wolves.All what Buck has done was not due to his reason and thought, but due to his fit. He was fit to everything surrounding him unconsciously and put him to the new way of living quickly.“The theory, ‘Survival of the fittest’, is the law of biological evolution which implies that plants or animals adapt to the environment to survive or to dieit is the biological survival rule of brutal biosphere.” That is to say, the key of this law is that those who can fit the environment can survive, on the contrary, those failed to fit would be obsolete under the rule of elimination.Peeping at Buck and his struggle, we can have a vision of us human that was also fighting in the battlefield with our matesand against our enemy. Filled with bustling stuff, we tried our best to stand on the top of right and authority only because that position would give us more materials and the sense of pride which we depended on to live. Flowers in the greenhouse didn’t know about the hardship of living, so they showed goodwill and send aroma to others; while life in the ice field where wind was blowing like knife and thick snow can bury people only showed a will of survive and cut up the useless goodness to wear on the coldness.We must do it because we had to do it. The pack of animal was like a society of people. Death and genocide would happen on us if we were not willing to fit the environment thoroughly. To dance with the shackle of survive of the fittest was the policy we should carry out forever, the reason why our human stood on the top of biologic chain, and the rule of living of every individual.My opinion on virtue and viceSome people had said virtue was the biggest treasure that human should obey. There is no doubt that kindness, loyalty, honor, love, companionship, sympathy, mercy, and other virtue should be followed. However, I argue that there is transformation between different virtue and even the virtue and vice.Showing the feature of three animals: dog, wolf and human, Buck was the bridge that connected the past and present. As the production of human civilization, dog was evolved from wolf and they would still howl on the wilderness if human didn’t raise and train them.Buck was a mirror from which we can see ourselves. Through this dog, writer told us that only in a place where sun darted its forth beams and everything was in order human will wear the coat of basic goodness, otherwise, kindness would be eliminatedif it met with the club and fang. In the cruel process of primitive accumulation of capitalism, mercy and sympathy was not needed for those quality can lead to death of innocent people. In the period of survive of the fittest, life was not concerned with civilization, while wilderness was the real marrow of life and echoing for the wilderness was the beginning of revival. Buck realized that “Mercy did not exist in the primordial life. It was misunderstood for fear, and such misunderstanding made for death.” This phenomenon can be seen in dogs as well as human. Wilderness were calling for human and eliminating the kindness in human’s heart stealthily.In A Treatise of Human Nature, British philosopher David Hume has said moral came from human’s emotion and conscience but not rationality. The essence of moral existed in the perceptual knowledge, but not rational knowledge. Therefore, the reason why moral distinctions had the division of virtue and vice was that the judgment of moral came from human’s attitude toward their internal actions and external objects. The judgment of moral came from our interest appeal; that is to say, the judgment of moral came from what was good to us, but not what is good.Let us think the question that which direction of Buck’s change to a beast was, progression or retrogression? The answer was that we can’t answer because he survived due to that he threw away those so called virtue and carry out those so called villainy. All what Buck did was under the pressure of living, and he responded to the call of the wild only because he wanted to live. Maybe in the comfortable and civilized Judge’s house, he would stick to the standard of moral and protect the respect of Judge’s riding wh ip by dying under his whip. But in this coldfield, sticking to those so called moral was a fool. Possibly in this kind of world, brutality, cold-bloodedness, cunning and so on was the moral.The division of virtue and vice was the refection of the division of civilization and wilderness to some degree. Maybe we can’t define what moral was and what vice was now in some scene, but we can try to last for enough time to seek for the answer.Run after the free lifeThe call from the wild stood for human’s natur e to run after a simple, independent and free life.Buck was bored of the complex life where he must deal with such a big net of relationship. He just wanted to run and leap through the forest, howled under the grey moonlight, ate what he liked and killed what he liked without many rules to obey. No one desired to live a complicated life for it’s difficult and tiring to reckon other people, while life in the wilderness was just that eat or eaten, kill or killed and there was no middle ground. Easy and simple life was set up on the uncivilized world where creatures didn’t have so much relation and elements to consider. Only being independent from all that can we find what we wanted.When unpracticed Charles and his relatives sunk in a ice hole, writer said th at “A yawning hole was all that was to be seen.” That hole was a capitalistic vast mouth that can eat people, but which would be rotten if we escaped from it. “Here a yellow stream flows from rotted moosehide sacks and sinks into the ground, with long grasses growing through it and vegetable mould overrunning it and hiding its yellow from the sun.” The gold that Thornton got has become a yellow stream because theywere eroded by natural power and lost their value. Imagine in a world where was entirely natural and uncivilized, gold, a kind of iron and currency, was entirely futile, isn’t it?Being free of human world and even free of materials, Buck got a totally new life where he can run at the head of the pack through the pale moonlight to release his vitality and got comfort from nature. We needed materials actually, but material was void actually. How can we get free? To get free of our hearts.ConclusionThere are two sentences I’d like to mention. First, human beings, never degenerate into beasts. Second, beasts, never degenerate into human beings. Correctness of those two sentences should be discussed.Human’s progression began in the point when human beings evolved from wilderness period to civilization, but the retrogression also began at the point when people shared the feast of civilization. For us who are far away from the wilderness and raised and trained by civilization, this book gives us a new vision.Sometimes a picture floating in my mind: in the icy forest, a silhouette of Buck as a wolf caned his neck to howl toward the pale moonlight to echo the howling of pack. That’s the song of animal, and the chant of human, and the snarl of life.野性的呼唤英文读后感英文版篇2The Call of the Wild is London’s most-read book, and generally considered his best, the most masterpiece of his so-called “early period“.The story was set in 19th-century Klondike Gold Rush, in which sled dogs were bought at generous prices.Buck was a domestic dog in Judge Miller’s home and living a comfortable life until he was sold secretly by the poor gardenerand became a sled dog. Buck was a Bernard dog weighed one hundred and forty pounds, tall, strong, and hea一vy muscled. He couldn’t accommodate to the harsh condition at first. And he wanted to fight, to escape, to go back to his cozy home, but in vain.The man in red taught him the law of stick and club-one must first adjust himself to his surroundings and learn the rules, and only after that he can do what he wants to do. The club of the man in red called back Buck’s nature as a dog.When he firstly served for Fran?ois and Perrault, two couriers, he showed his superior ability to adapt to the environment and his smartness to learn everything he wanted to learn. Curly’s death astonished him and taught him to be cautious. And before he had recovered from the shock caused by the tragic passing of Curly, he was harnessed as a sled dog and step by step wanted to be the leader. But the leading dog, Spitz, was already an excellent one, who also considered Buck as enemy and potential competitor. At last, when Spitz once punished him, hurling backward Buck, he knew the time had come. He killed Spitz and took his place.When they pulled into Dawson, Buck was sold as useless thing to three gold diggers, who weren’t veteran in sledding and even didn’t k now how to get to their destination. Food was eaten up half way. So Charles, one of the three, decided to kill Buck when he couldn’t get up. However, when he aimed at Buck, John Thornton sprang upon him, knocked him down and told him that if Charles stroke Buck, Thornton would kill him.Thus, Thornton took Buck away. He was the only true friend of Buck. But Buck was a thing of the wild, especially when the calling of wolf from the hills. Once when he came back from hills,he found that Thornton was killed by Indians. What would you do if you were Buck when your beloved friend was killed? Buck became a nut and killed those headsmen and stayed with Thornton for two days and nights, never lea一ving Thornton out of his sight. And then a nearby wolf howl captures his ears, and he follows the sound to an approaching wolf pack, battling several of these creatures to prove his worth.野性的呼唤英文读后感英文版篇3At the beginning of this century, many new writers emerged with the introduction of many new ideas. Among them, Jack London was the most popular one.His most famous novel is the call of the wild . Although it is a story about a dog, Buck, it vividly depicts the life in the primitive North where people rushed for gold and fortune.Buck, used to belong to a judge, was kidnapped and sold to North. Then he became a member of a dog-team pulling a sled . In the days of pulling a snow-sled, he learned to conform to the law of nature and obey the master. Finally, he found a basic instinct hidden inside him, which enabled himself to survive the tough environment. This is the call of the wild.When you read the story, you will feel that Buck is a man instead of a dog, struggling with his fortune and conforming to the law of nature.Though short, it is really a thrilling story. What you never forget is the tough life in the nature, the brave and crafty dog. Maybe the wild is calling you to go ahead.While writing for only 16 years throughout his life, London produced an amazing body of work among which, White Fang, Martin Eden, the Valley of the Moon are representative.野性的呼唤英文读后感英文版篇4" He sings a song of the younger world, which is the song of the pack." (Chapter VII The Sounding of the Wild) When the last sentence vanished from my eyes, I can still perceive an echo of a song - a wild song, which knocks up my dizzy mind that always cheerfully sink into the so-called civilized world without questioning. Wild, is no longer a symbol of the law of jungle but a headspring where streams out love, passion, bravery, loyalty, friendship, venture, competition and tolerance all these virtues can easily be found in the Call of the Wild.Jack London (1876-1916) is a worldwide renowned novelist. His stories successfully reflect the contradictory views of man’s nature and destiny in and against the wild, and his "fight to survive" notion has gained him and his works timeless popularity, particularly, the Call of the WildIt tells a story of a gigantic dog, named Buck, who is stolen from a rich and comfortable home and forced to learn to survive as an Alaskan sled dog. Buck, at first, is too savage for the company of man until he coincidently encounters his beloved master-kindhearted John Thornton. Finally, John’s incidental death breaks Buck’s last tie to the man and drives him into his long-desired wild with his pack. In the story, Buck and John simply adopt themselves to answer the call of the wild. When it comes to Buck’s mind that one day he will eventually leave John- his master, all he wants to do is just to help him finish the gold-rush-trip. He " from then on, night and day, never put a halt, in desperation, he burst into long stretch of flight, did not to stay him (John)…" (Chapter VII The Sounding of The Wild) Buck wished to remember John’s image forever, he "for two days and nights never left camp, never let Thornton out of his sight. He followed him about at his work, watched him while saw him intoblankets at night and out of them in the morning…" (Chapter VII) When I read these words I just could not hold my tears bursting. Can a real man devote himself to loyalty and friendship in such a way? On the other hand, John Thornton is not only a dog-lover but also a brave and venturous man. He is so straightforward and simple that makes him an accommodating man. Once he firmly roots a goal into his heart, it seems that nothing could prevent him from accomplishing it except death. I do not know whether the persistence is the most vital element to make a man successful, but what I know is that you are not far away from success once you occupy it.It is Jack London who plunges me into the animated wild from the hustle-and-bustle and from desperate city. There, I merely cannot deny the attraction of Buck’s bark, which enlightens me to pursue another lost half of the nature in mankind, and to dig out a true meaning of life. Dare we imagine that London intentionally employs Buck to set us a model with perfect characters (count barbarity out)? The answer is affirmed. We, as animals, are from the wild but shedding off more and more wild signs, which demonstrate us as the "uncivilized". However, who can fully guarantee that we have not overlooked some essential wild-endowed virtues? Especially, nowadays, it seems more crucial for us to stop looking at the post-industrialized world and to ponder for a while. When cheats, betrayals, lies, lusts and crimes stuff a materialized society, whether London uses this novel to help himself escape the reality or warn the earthy people, to us, modern man, is all the same.() It appears horrible that in modern society many people are enthusiastically talking about how to build up "special relations" to the authority, deceiving and lying to each other.To them life is a mask-wearing process rather than a hard work. Every time, you browse WebPages, scandals in politics, business, the entertainment circle and even on campus crowd into your eyes. Oh, what is the essence of human beings? What is the civilization to us? Do we need to look back at where we came from? Is it good or bad for us to speak out what we think and to do what the consciences demand us to? Are we wasting talents given by the mighty nature? Be an honest, straightforward, warmhearted, emotional and responsible man or be a shrewd, cold hearted and astute hypocrite? While embracing the "civilized" rubbish, we are losing those good virtues, which are the calls of the wild. Once we lose them, we are to lose ourselves, and we will get nowhere. I wish this dreadful thought is totally a fallacy, but, now, it is chilling me hard.One day when I happen to stand on the top of a grand mountain to observe a boundless prairie enveloped by the sapphire firmament and combed by gusts of the rhythmical west wind, a morning sun sprinkles me her warmth and brilliance in a graceful way, however, at that moment, I am afraid that I cannot appreciate these beauties, I am a lost " civilized man" then.野性的.呼唤英文读后感英文版篇5The story sounds like just a dog tale at first--a dog, Buck, is kidnapped from his comfortable life in California and sold as a sled dog for the Alaskan gold rush. While he endures the wilderness and the other dogs, Buck learns that survival comes only with tooth and fang. This lesson brings him very close to his forbears, the wolves.If you look deeper, Call of the Wild is as much a story of humans as it is a dog tale. Buck encounters various incompetent masters who try to break his spirit. Are we like this? But Buck alsolearns to trust a master who is gentle and gives love. We can be like this, too.Call of the Wild is not a story for the squeamish or very young. By involving us in the characters lives, Jack London tells the truth. It is a life-and-death war between the harsh land and the soul every day. There is blood, death, cruelty--but its the truth. 野性的呼唤英文读后感英文版篇6Book review: The call of the wildAs a type of novelette, I wasnt used to this cos Ive just finished HarryPotter so in occasions novelette wrote very briefly. The background of the author was very poor, and precisely the time to seek gold. Part of the novel means to expose the hardness of dogs at that time. Men were crazy about gold, the main character, Buck, was stolen by a Gardener of a lawyer who owns Buck.The man with the red sweater taught him the law of clubs, this was a good beginning. The trading road led him at last to two couriers, who knew how to treat dogs. Then the dog team was traded to a three-people family who were seeking good in Alaska. But they didnt know how to treat dogs and at last dogs and men were drowned in the water, except Buck. He was picked up by a man. And eventually Buck was back to the wild-where his ancestors had been.In my opinion a good novel could make readers cry, yell, etc.I clenched my fist when the Family treated the dog team badly, and had a wonderful feeling when the man picked up Buck and treated him like his own son. I t had feeling, this novel…野性的呼唤英文读后感英文版篇7As a dignified individual, survival seems to be the subject of our discussion forever. But in this hard way of survival, the desirefor "life", often let us forget the species. Buck was one of those dogs who worked hard to survive, developed a knack for hardship and eventually became the leader of the pack. But whether it is Barker, or the authors other characters, their hearts are full of longing and yearning for "life". But in this extreme environment and the human strength of the collision, we face the cruelty of competition, witness the true meaning of life.The hero of the novel is a dog named Buck. Set during the Alaskan Gold Rush, the story follows Buck as he climbs from a domesticated Southern dog to a barbarian state in order to survive in the treacherous conditions of the North. Buck is a huge cross dog, he was secretly sold from the family of the south, after several difficulties began to set foot on the road of gold, became a sled working dog, in the cruel domestication process, he realized the justice and the law of nature, the harsh living environment taught him the meaning of cunning and deceit, He took his own cunning and deceit to an unsurpassed level, and after a brutal, even mortal, struggle, he finally established himself as the leader dog. We can get a sense of the mental outlook of different people through the change of owners during the arduous sledding journey. It was in these movements, too, that Buck formed a deep and deep bond with the last master, who had rescued him from the most strenuous drudgery, and whom he had rescued many times. Finally, after the tragic death of his beloved master, he went out into the wilderness, answering the ancient wild call he had heard and yearned for so many times along the way.Buck was only a dog, but his arduous path reflected the true meaning of personal struggle in the age in which the writer lived. It was also a reflection of the naturalism prevalent in Americansociety during the period of the treacherous development of capitalism. On this road, in such a dangerous natural and social environment, only the elite and the strong have the possibility of survival. If they lack the ability to adapt to the changing conditions, it means a quick and tragic death. In front of the laws of nature, man is insignificant and helpless. Moreover, in the struggle for existence, any moral concept becomes "a kind of vanity and an obstacle". On the one hand, this shows the sinister living environment at that time, on the other hand, it also reveals the immoral side of the capitalist society. In such a society, under the action of natural law, the primitive desire, moral decay, the loss of civilization, all show incisively and vividly. Therefore, if survival is the highest goal of human activity, then the process of animal survival is the process of violent meeting and killing each other. Only through the struggle of the law of the jungle, can we ensure the continued survival of the "elite" or "strong" with competitive advantages. Therefore, it fully expresses the authors naturalism thought.The more civilized man is, the more stable his life is, so that in a civilized society things are laid out clearly and there are few accidents. But when something goes wrong, and its serious enough, its the end of the world for those who cant adapt. And Bucks experience also tells us: life is often intense and painful, but in fact it is more full of vitality and vitality and we want to be the strong of life.Thats what survival is all about. There is no justice. Once youre down, youre down. So be careful not to fall. Life on the road, there is no plain sailing, there is no constant, he often changes patterns to teach us to be strong, and we have to do is to accept his arrangement, in perseverance through the cold。

我看见漂亮的植物英语作文

I have always been captivated by the beauty of nature, and one of the most enchanting aspects of it is the diverse array of plants that grace our world. My fascination with plants began at a young age, when I would accompany my grandmother on her daily walks through the lush gardens that surrounded our home. It was during these walks that I first laid eyes on a plant that would forever hold a special place in my heart.The plant in question was a vibrant, exotic species that stood out among the other flora. It was a type of orchid, with petals that were a deep, rich purple, almost velvety to the touch. The center of the flower was a striking contrast, a bright yellow that seemed to glow against the backdrop of the purple petals. The sight of this plant was nothing short of mesmerizing, and I found myself drawn to it in a way that I couldnt quite explain.As I grew older, my interest in plants only deepened. I began to study botany in school, learning about the various species of plants, their habitats, and the unique characteristics that set them apart. I was particularly fascinated by the way plants interact with their environment, and the complex relationships they form with other organisms. This led me to explore the world of ecology, where I discovered the intricate balance that exists within ecosystems and the vital role that plants play in maintaining this balance.One of the most remarkable aspects of plants is their ability to adapt to a wide range of conditions. From the arid deserts to the dense rainforests, plants have evolved to thrive in some of the most inhospitable environments on Earth. This adaptability is a testament to the resilience oflife and the incredible diversity of the natural world.In addition to their ecological importance, plants also hold a significant place in human culture. Throughout history, plants have been used for a variety of purposes, from medicinal remedies to culinary delights. Many cultures have developed deep connections with specific plants, incorporating them into their rituals, myths, and daily lives. This relationship between humans and plants is a beautiful example of the interconnectedness of all living things.As I continued to explore the world of plants, I was struck by the sheer variety of forms and colors that exist. From the towering redwoods to the delicate orchids, each plant is a unique masterpiece, crafted by the hand of nature. The more I learned, the more I came to appreciate the intricate details of each species, from the intricate patterns on a leaf to the subtle shades of a flower.One of the most rewarding aspects of my journey with plants has been the opportunity to cultivate my own garden. There is something incredibly satisfying about nurturing a plant from a tiny seedling to a thriving, beautiful specimen. Watching a plant grow and flourish under your care is a humbling experience, and it serves as a reminder of the importance of patience and care in all aspects of life.In conclusion, my encounters with beautiful plants have been a source of endless wonder and inspiration. They have taught me about the resilience of life, the interconnectedness of all living things, and the importance ofnurturing and protecting our natural world. As I continue to explore the fascinating world of plants, I am constantly reminded of the beauty, complexity, and wonder that exists all around us.。

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Since the time of the earliest humans, people have attempted to understand the natural environment. We have observed our surroundings and searched for explanations for natural phenomena. Yet despite our persistence over thousands of years, many basic questions remain to be answered. Although we understand core processes such as photosynthesis, we do not have a full understanding of issues such as how plants maximize their photosynthetic capacity.
Specific leaf area, or SLA, plays a prominent role in ecological theories that attempt to provide explanations for plant and ecosystem function. SLA, a measurement of the total leaf area to dry mass, has been found to correlate with the potential for light-resource use, the relative growth rate of a plant, and differences in essential nutrient demand and habitat preference.
Scientists also have observed that the SLA of individual leaves varies within a single plant, and this measurement often correlates with leaf maturation and position within the canopy. More recently, scientists have discovered that, as a tree increases in size, its total canopy SLA decreases -- that is to say, its total leaf surface area fails to keep pace with increases in total leaf mass.
What causes this decrease in SLA as tree size increases has remained a mystery, but recent research by Cornell University scientists Karl Niklas and Edward Cobb published in the January issue of the American Journal of Botany provides an explanation for this decrease in SLA with an increase in tree size.
"The traditional explanation for the size-dependent decrease in SLA was never very satisfying," Niklas said. "We wanted to look at this phenomena in greater details with more care, and we found a totally different answer to a classic ecological question."
The commonly accepted hypothesis has been that decreasing SLA in trees of increasing size is a result of leaf-by-leaf acclimation to the local environment. Physical factors such as differences in light intensity are affected by differences in leaf position within the canopy, providing different local environments. Niklas and Cobb hypothesized that changes in SLA may be a result of changes in the relative numbers of different shoot types that produce leaves differing in SLAs --a developmental shift that occurs as a tree increases in size.
Niklas and Cobb examined 15 red maple trees that differed in trunk size and found that the changes in SLA can be attributed to shoot type rather than to the location of the leaves within
the canopy. As the trunk diameter increased, the number of short-shoots increased rapidly relative to the number of long-shoots. Detailed analyses of the largest tree demonstrated that short shoots, on average, produce leaves with smaller specific leaf areas than those produced by long shoots. Consequently, developmental shifts occurring at the shoot and whole plant level account for size-dependent decreases in total canopy SLA, rather than leaf-by-leaf acclimation to the local environment.
Mathematical models for the distribution of light within the canopy predict that the photosynthetic rate of the entire canopy is maximized when the specific leaf area is lowest for leaves at the top of the canopy. This research provides new insight into the mechanism by which trees have evolved to obtain light and photosynthesize at the greatest rate.
"Our research shows that plants are highly integrated organisms that respond to their environments in ways that are every bit as complex as even the most sophisticated animals," Niklas said. "This research also shows that we still have plenty to learn about phenomena that we thought we understood very well."
Adapted from materials provided by American Journal of Botany, via EurekAlert!, a service of AAAS.。