Life on earth
生活在地球上的人 英语
生活在地球上的人英语英文回答：Life on Earth is a complex and dynamic phenomenon that has fascinated scientists, philosophers, and theologiansfor centuries. The study of life on Earth, known as biology, seeks to understand the origins, diversity, and behavior of living organisms. From the smallest bacteria to the largest whales, life on Earth exhibits an astonishing array offorms and functions.One of the most fundamental characteristics of life is its capacity for self-organization and reproduction. Living organisms are able to maintain their internal organization and respond to changes in their environment. They also have the ability to reproduce, creating new individuals thatcarry on their genetic heritage.The diversity of life on Earth is truly staggering. Scientists have identified over 1.9 million species ofanimals, plants, fungi, and microorganisms, and it is estimated that there may be as many as 10 million species yet to be discovered. This diversity is a result ofbillions of years of evolution, during which organisms have adapted to a wide range of habitats and ecological niches.The behavior of living organisms is another fascinating aspect of life on Earth. Animals exhibit a wide range of behaviors, from simple reflexes to complex social interactions. Plants also exhibit a variety of behaviors, such as photosynthesis, growth, and reproduction. These behaviors are essential for the survival and success of living organisms.Life on Earth is not static, but rather is constantly evolving. Over time, natural selection and other evolutionary forces shape the traits of organisms, leading to the emergence of new species and the extinction of others. This process of evolution has resulted in the incredible diversity of life that we see today.The study of life on Earth has profound implicationsfor our understanding of ourselves and our place in the universe. By studying the origins and evolution of life, we can gain insights into the nature of consciousness, the meaning of existence, and the possibility of life beyond Earth.中文回答：地球上生命是一个复杂而充满活力的现象，它已经让科学家、哲学家和神学家着迷了几个世纪。
地球生命的演变英语作文100字
地球生命的演变英语作文100字英文回答：The evolution of life on Earth is an awe-inspiring and complex process that has spanned billions of years. It is estimated that the Earth is about 4.5 billion years old, and the first evidence of life on the planet dates back to about 3.5 billion years ago. Life on Earth has undergone numerous changes and adaptations over time, from the first simple cells to the complex and diverse organisms that we see today.One of the most important milestones in the evolution of life on Earth was the development of photosynthesis. This process, which is carried out by plants and other organisms, converts sunlight into chemical energy that can be used to fuel life. Photosynthesis allowed for the evolution of more complex organisms, as it provided a reliable source of energy.Another major milestone in the evolution of life on Earth was the development of eukaryotic cells. Eukaryotic cells are more complex than prokaryotic cells, and they contain a nucleus and other organelles. The development of eukaryotic cells allowed for the evolution of more complex organisms, including animals, plants, and fungi.The evolution of life on Earth is an ongoing process, and it is likely that there will be many more changes and adaptations in the future. The planet is constantly changing, and the organisms that live on it must adapt in order to survive. The evolution of life on Earth is a testament to the resilience and adaptability of life, and it is a story that is still being written.中文回答：地球生命的演化是一个令人惊叹且复杂的过程，已经历经了数十亿年。
Unit 9 Is There Life on Earth课文翻译大学英语一教学文案
U n i t9I s T h e r e L i f e o n E a r t h课文翻译大学英语一Unit 9 Is There Life on Earth?It is humorous essay. But after reading it you will surely find that the author is most serious in writing it.There was great excitement on the planet of Venus this week. For the first time Venusian scientists managed to land a satellite on the plant Earth, and is has been sending back signals as well as photographs ever since.The satellite was directed into an area know as Manhattan (named after the great Venusian astronomer Prof. Manhattan, who first discovered it with his telescope 20,000 light years ago).Because of excellent weather conditions and extremely strong signals, Venusian scientists were able to get valuable information as to the feasibility of a manned flying saucer landing on Earth. A press conference was held at the Venus Institute of Technology."We have come to the conclusion, based on last week's satellite landing," Prof. Zog said, "that there is no life on Earth.""How do you know this?" the science reporter of the Venus Evening Star asked."For one thing, Earth's surface in the area of Manhattan is composed of solid concrete and nothing can grow there. For another, the atmosphere is filled with carbon monoxide and other deadly gases and nobody could possibly breather this air and survive.""What does this mean as far as our flying sauce program is concerned?""We shall have to take our own oxygen with us, which means a much heavier flying saucer than we originally planned.""Are there any other hazards that you discovered in your studier?""Take a look at this photo. You see this dark black cloud hovering over the surface of Earth? We call this the Consolidated Edison Belt. We don't know what it is made of, but it could give us a lot of trouble and we shall have to make further tests before we send a Venus Being there.""Over here you will notice what seems to be a river, but the satellite findings indicate it is polluted and the water is unfit to drink. This means we shall have to carry our own water, which will add even greater weight to the saucer.""Sir, what are all those tiny black spots on the photographs?""We're not certain. They seem to be metal particles that move along certain paths. They emit gases, make noise and keep crashing into each other. There are so many of these paths and so many metal particles that it is impossible to land a flying saucer without its being smashed by one.""What are those stalagmite projections sticking up?""They're some type of granite formations that give off light at night. Prof. Glom has named them skyscrapers since they seem to be scraping the skies.""If all you say is true, won't this set back the flying saucer program several years?""Yes, but we shall proceed as soon as the Grubstart gives us the added funds.""Prof. Zog, why are we spending billions and billions of zilches to land a flying saucer on Earth when there is no life there?"Because if we Venusians can learn to breathe in an Earth atmosphere, then we can live anywhere."这是一篇幽默小品。
保护环境英语标语大全
保护环境英语标语大全保护环境英语标语11、保护树木是第一。
Protection of trees is the first.2、珍惜资源永续利用。
Cherish the sustainable use of resources.3、为了地球上的生命。
For life on earth.4、心中有情，脚下留情。
The hearts of love, at the foot of mercy.5、绿色生活，环保相伴。
Green life, accompanied by environmental protection.6、足下轻轻，手下留情。
Your hand gently.7、痰吐在地，辱写在心。
Spit on the ground, shame on the heart.8、美化生活，净化心灵。
Beautify life, purify the soul.9、绿化家园，文明人心。
Green homes, civilized people.10、疏忽一时，痛苦一世。
A moment of neglect.11、绿草荫荫，润了我心。
The shadow of the green grass runs my heart.12、让小鸟拥有一片蓝天。
Let the birds have a blue sky.13、绿化环境，净化心灵。
Green environment, purify the mind.14、让白色染污永远消失！Let the white pollution disappear forever!15、你的行动代表花的未来。
Your actions represent the future of flowers.16、环境保护是一项基本国策。
Environmental protection is a basic national policy.17、花草造福人，人人护花草。
Flowers and plants for the benefit of everyone, care for flowers and plants.18、留住草的美，体现你的美。
地球上的每个生命英语作文
地球上的每个生命英语作文Every Life on Earth。
As we look around the world, we can see countless forms of life. From the tiniest microorganisms to the largest mammals, every living being on Earth plays a role in the delicate balance of our planet's ecosystem. In this essay, we will explore some of the most fascinating and important forms of life on Earth.One of the most important forms of life on Earth is plants. Without plants, there would be no oxygen for us to breathe, and no food for us to eat. Plants are also essential for maintaining the balance of carbon dioxide in the atmosphere, which helps to regulate the Earth's temperature. From towering trees to delicate flowers, plants come in all shapes and sizes, and they are found in every environment on Earth.Another important form of life on Earth is insects.Although they may seem small and insignificant, insects play a crucial role in pollinating plants, controlling pests, and decomposing organic matter. Without insects, many of the plants and animals we rely on for food would not exist.Of course, we cannot forget about the animals that inhabit our planet. From the majestic elephants of Africa to the playful dolphins of the ocean, animals are a source of wonder and inspiration for humans. They also play important roles in maintaining the balance of ecosystems, from grazing on grass to controlling populations of other animals.Finally, we must consider the microorganisms that exist all around us. From bacteria to viruses, these tiny organisms are essential for maintaining the health of our planet. They help to break down organic matter, regulate the nitrogen cycle, and even play a role in the weather.In conclusion, every life on Earth is important and plays a vital role in the delicate balance of our planet'secosystem. From the smallest microorganisms to the largest mammals, each form of life has its own unique contribution to make. As humans, it is our responsibility to protect and preserve these forms of life for future generations.。
全新版大学英语2 Unit 8 text B
To adjust to these chemicals would require time on the scale that is nature’s; it would require not merely the years of a man’s life but the life of generations. And even this, were it by some miracle possible, would be futile, for the new chemicals come from our laboratories in an endless stream; almost five hundred annually find their way into actual use in the United States alone. The figure is staggering and its implications are not easily grasped—500 new chemicals to which the bodies of men and animals are required somehow to adapt each year, chemicals totally outside the limits of biologic experience.
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The rapidity of change and the speed with 新情况产生的速度和变化 which new situations are created follow 之快已反映出人们激烈而 the rush and heedless pace of man rather 轻率的步伐胜过了大自然 than the deliberate pace of nature. 的从容步态。放射性远在 Radiation is no longer merely the 地球上还没有任何生命以 background radiation of rocks, the 前就已经存在于岩石放射 性本底、宇宙射线爆炸和 bombardment of cosmic rays, the 太阳紫外线中了；现在的 ultraviolet of the sun that have existed 放射性是人们干预原子时 before there was any life on earth; 的人工创造。生命在本身 radiation isnow the unnatural creation of 调整中所遭遇的化学物质 man’s interfere with the atom. The 再也远远不仅是从岩石里 chemicals to which life is asked to make 冲刷出来的和由江河带到 its adjustmentare no longer merely the 大海去的钙、硅、铜以及 calcium and silica and copper and all the 其他的无机物了，它们是 人们发达的头脑在实验室 rest of the minerals washed out of the 里所创造的人工合成物， rocks and carried in rivers to the sea; they 而这些东西在自然界是没 are the synthetic creations of man’s 有对应物的。 inventive mind, brewed in his laboratories, and having no counterparts in nature.
地球生命的起源-英文版(origin of life on earth)
© 2009 SCIENTIFIC AMERICAN, INC.
September 2009
© 2009 SCIENTIFIC AMERICAN, INC.
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another, and eventually to turn into the lifeforms we know.
On the other hand, the paradox would disappear if the first organisms did not require proteins at all. Recent experiments suggest it would have been possible for genetic molecules similar to DNA or to its close relative RNA to form spontaneously. And because these molecules can curl up in different shapes and act as rudimentary catalysts, they may have become able to copy themselves—to reproduce—without the need for proteins. The earliest forms of life could have been simple membranes made of fatty acids—also structures known to form spontaneously—that enveloped water and these self-replicating genetic molecules. The genetic material would encode the traits that each generation handed down to the next, just as DNA does in all things that are alive today. Fortuitous mutations, appearing at random in the copying process, would then propel evolution, enabling these early cells to adapt to their environment, to compete with one
保护环境的英文句子带翻译
保护环境的英文句子带翻译1、We are using up our natural resources and at the same time polluting our environment with dangerous chemicals. If we continue to do this, life on earth cannot survive.我们一边耗尽自然资源，一边产生化学污染物。
如果继续这样做的话，地球上的生物将难以生存。
2、Protecting the environment is every man's responsibility.保护地球环境是每一个人的责任。
3、if everyone could make a big contribution to environmental protection, our home will become much more beautiful.如果每个人为环境保护作出一点贡献，我们的家园会变得更加美丽。
4、Protecting the environment，everyone，s duty.保护环境，人人有责。
5、The short life of the flowers away, leaving behind the beauty is forever.带走的花儿生命短暂，留下的美丽才是永远。
6、Governments of many countries have established laws to protect the air, forests and sea resources and to stop environmental pollution.许多国家制定了法律来保护大气、森林和海洋资源，制止环境污染。
7、The protection of trees, that is, to protect themselves。
来自地球的生命作文英语
来自地球的生命作文英语Possible essay:Life on Earth。
Life on Earth is incredibly diverse and resilient. From the tiniest microbes to the largest mammals, from the hottest deserts to the coldest poles, from the earliest fossils to the latest discoveries, life has adapted and evolved over billions of years to thrive in almost every environment imaginable. Yet, despite this abundance and complexity, all life on Earth shares a common origin and a common destiny.According to the theory of evolution, life on Earth began as simple, single-celled organisms that emerged from the primordial soup of chemicals and energy that existed on the early Earth. Over time, these organisms diversified and specialized into different forms, some of which developed complex structures and functions, such as photosynthesis,respiration, movement, reproduction, and communication. The evolution of life was driven by various factors, such as natural selection, mutation, genetic drift, and environmental changes, which favored certain traits and behaviors that enhanced survival and reproduction.Today, life on Earth includes millions of species of plants, animals, fungi, and bacteria, each with its own unique adaptations and niches. Some species are highly specialized and restricted to specific habitats, such as deep-sea vents, hot springs, or polar ice caps, whileothers are more generalist and adaptable, such as humans, rats, or cockroaches. Some species are endangered orextinct due to human activities, such as habitat destruction, pollution, climate change, or overexploitation, while others are thriving and expanding, such as invasive species or pests.Despite the diversity of life on Earth, all livingthings share certain fundamental characteristics, such asthe ability to grow, reproduce, respond to stimuli,maintain homeostasis, and use energy. These characteristicsare based on the molecular and cellular structures and processes that underlie all life, such as DNA, RNA, proteins, membranes, organelles, metabolism, and signaling. By studying the similarities and differences among living things, scientists can trace the history and relationships of life on Earth, and develop new insights and applications in fields such as medicine, agriculture, biotechnology, and ecology.In conclusion, life on Earth is a remarkable and ongoing story of adaptation, diversity, and interconnectedness. From the simplest microbes to the most complex ecosystems, from the past to the present, from the microscopic to the cosmic, life on Earth reveals the wonders and mysteries of nature and the potential and limitations of human knowledge and stewardship. As we continue to explore and understand the origins and evolution of life on Earth, we also face the challenges and opportunities of preserving and enhancing the diversity and sustainability of life for future generations.。
The Origins of Life on Earth
The Origins of Life on Earth 地球上的生命起源自地球形成以来，生命在地球上的存在已经持续了几十亿年。
然而，生命是如何起源的仍然是科学家们一直在研究的课题。
虽然还有很多未知的领域，但是目前的研究已经证明了生命可能来自于一些非常普遍的物质。
1. 活性物质生命的基本单位是细胞。
细胞是由生物大分子（例如蛋白质和核酸）以及一些非生物分子（例如脂肪酸和糖）组成的。
这些分子可以相互作用，形成复杂的化学反应网络，也可以产生类似细胞的结构。
这种涌现性质是活性物质的一种表现形式，也是生命起源的可能机制之一。
活性物质是指在某些特定条件下，类似于生物系统中的物质发生的非均衡状态。
这种状态可以让系统内部的分子之间发生相互作用，从而形成复杂的结构和组织。
而这些组织和结构可以模拟细胞的功能，这表明活性物质可能是生命起源的一种机制。
2. DNA和RNA的起源DNA和RNA是构成生物基因组的两种核酸。
生命起源的一种理论是，DNA和RNA可能起源于一种更为简单的分子。
这个分子被称为核苷酸，是由磷酸基团、核苷和糖分子组成的。
分子生物学家已经证实，核苷酸可以通过自我组装和化学反应形成RNA和DNA分子。
这可能是生命起源的一种机制。
值得一提的是，这种机制还需要一定的物理和化学条件来促进分子的自组装和稳定性，例如高温、高盐等环境。
3. 受光时间触发的化学反应受光时间（photoperiod）指的是某个化学反应之中外部光源的影响。
理论上，这种化学反应可以形成像DNA这样的复杂分子。
化学家已成功地使用类似光和电等外部刺激，形成了一些基本的生物分子，如氨基酸和糖。
然而，在光的作用下形成这些大分子仅仅是生命起源的第一步。
分子之间需要相互作用，形成更加稳定的结构，并能够遗传相应的信息才能构成生命的基本单位——细胞。
总结在生命起源这个问题上，我们已经取得了很大的进展。
虽然还有许多未知领域，但是科学家们已经证实了许多可能的起源机制。
现代大学英语精读unit6 life on earth
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If microbes can live…not so shabby.
1.What are the two conditions given in this statement? They refer to places without water or air or sunlight, and places where the temperature is extremely high. 2. What is meant by “Then they might find a place like Mars not so shabby”? Notice the tone of the sentence.
原因是：1）宇宙像是适合生命存在的地方；2）如果有生命存在， 生物会发出可以被探测到的、表明其存在的记号。
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…life radiates information about itself-that ,if nothing else,it usually leaves a residue,an imprint,an echo.
这个浅显的事实是：外星生物既然是宇宙其他行星的生 物，就不能轻而易举地找到。
Para. 13
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What are the reasons, according to the author, which sustain the search for alien organisms?
The reasons are: 1) the universe looks to be a place suitable for the existence of life; 2) if that is the case, life will give out signs of its existence and these can be detected.
想象生活在地球上英语作文
想象生活在地球上英语作文标题，Imagining Life on Earth An English Essay。
Living on Earth, the blue gem floating in the vast expanse of the universe, is an experience that sparks the imagination and fills the soul with wonder. From the towering mountains to the deepest oceans, Earth is a canvas painted with the hues of life in all its forms. In this essay, we will delve into the intricacies of life on Earth, exploring its beauty, challenges, and the profound connection shared by all its inhabitants.To begin with, one cannot help but marvel at the sheer diversity of life on our planet. From the smallest microorganisms to the largest mammals, Earth teems with an astonishing array of species, each adapted to its own unique niche in the ecosystem. The lush rainforests of the Amazon, the vast savannas of Africa, and the icy landscapes of the Arctic all harbor life in its myriad forms, creating a tapestry of biodiversity unrivaled anywhere else in thecosmos.Moreover, the interconnectedness of life on Earth is a testament to the intricate web of relationships that sustains our planet. Every organism, no matter how small or seemingly insignificant, plays a crucial role in maintaining the delicate balance of ecosystems. From pollinators ensuring the reproduction of flowering plants to predators regulating prey populations, each species contributes to the overall health and resilience of the biosphere.However, alongside its beauty, life on Earth also presents us with formidable challenges. Human activities, ranging from deforestation to pollution, have taken a toll on the planet's ecosystems, leading to habitat loss, species extinction, and climate change. The consequences of these actions are profound, affecting not only the natural world but also human societies that depend on it for their livelihoods and well-being.In the face of these challenges, it is imperative thatwe recognize our shared responsibility as stewards of the Earth. By adopting sustainable practices and embracing conservation efforts, we can work towards preserving the planet for future generations. From reducing our carbon footprint to protecting vulnerable ecosystems, there are countless ways in which each of us can make a positive impact on the world around us.Furthermore, fostering a deep appreciation for the natural world can enrich our lives in profound ways. Whether it's marveling at the intricate patterns of a spider's web or basking in the tranquility of a forest grove, connecting with nature can nourish the soul and instill a sense of awe and reverence for the world around us. By cultivating this connection, we can cultivate a deeper sense of empathy and compassion for all living beings, fostering a more harmonious relationship with the Earth.In conclusion, life on Earth is a remarkable journey filled with beauty, challenges, and the interconnectedness of all living things. As inhabitants of this preciousplanet, it is our duty to cherish and protect it for generations to come. By embracing sustainability, conservation, and a deep reverence for the natural world, we can ensure that Earth remains a beacon of life and wonder in the vast expanse of the cosmos.This essay, inspired by the wonders of life on Earth, serves as a testament to the boundless potential of human imagination and the profound connection shared by all living beings. As we continue to explore and learn more about our planet, may we never lose sight of the awe and wonder that surround us each and every day.。
地球上的生活英语作文
地球上的生活英语作文英文回答：Life on Earth is a mesmerizing symphony of interconnectedness, where myriad species, from the smallest microorganisms to the largest whales, play vital roles in maintaining the delicate balance of our planet. Theintricate tapestry of life has evolved over billions of years, shaped by the relentless forces of natural selection and adaptation.Each organism, no matter how humble, contributes to the web of life. Microbes, the unseen architects of ecosystems, decompose organic matter, recycle nutrients, and form symbiotic relationships with plants and animals. Plants, the primary producers, harness sunlight through photosynthesis, converting carbon dioxide and water into glucose, the fuel that sustains all life. Animals, fromtiny insects to formidable predators, consume plants or other animals, transferring energy and nutrients throughintricate food chains and webs.The diversity of life on Earth is staggering, encompassing an estimated 8.7 million species, each withits unique adaptations and ecological niche. From the vibrant coral reefs teeming with marine life to the lush rainforests that house an astonishing array of flora and fauna, the planet is a vibrant mosaic of habitats, each harboring its own distinctive community of organisms.Human beings, with our advanced cognitive abilities and capacity for technological innovation, have a profound impact on the biosphere. While we possess the power to harness the Earth's resources and shape our environment, we also bear the responsibility to steward our planet for future generations. Understanding the intricacies of life on Earth is crucial for ensuring the sustainability of our own species and the countless others with whom we sharethis remarkable planet.中文回答：地球上的生命是一个令人着迷的相互联系的交响曲，从最小的微生物到最大的鲸鱼，无数的物种在维持我们星球的微妙平衡中扮演着至关重要的角色。
地球上的生命英语作文
地球上的生命英语作文Life on Earth is a delicate and complex system that is constantly evolving and adapting to the ever-changing environment. From the tiniest bacteria to the largest mammals, every living organism plays a crucial role in maintaining the balance of nature. 地球上的生命是一个复杂而微妙的系统，不断发展和适应着不断变化的环境。
从最微小的细菌到最大的哺乳动物，每个生物在维持自然平衡中都发挥着至关重要的作用。
Plants, for example, are not only a source of oxygen for humans and animals, but also provide food and habitat for a wide variety of species. They are the foundation of the food chain, sustaining life at every level of the ecosystem. 植物不仅是人类和动物的氧气来源，还为各种物种提供食物和栖息地。
它们是食物链的基础，维持着生态系统各个层次的生命。
Animals, on the other hand, play a crucial role in seed dispersal, pollination, and maintaining biodiversity. They contribute to the health of ecosystems by controlling populations of other species and recycling nutrients through their activities. 另一方面，动物在种子传播、授粉和维持生物多样性方面发挥着至关重要的作用。
unit9-Is-There-Life-on-Earth
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Topic-related Vidio
To Save The Earth
但是近些年来，由于工业化污染的日益严重，我们的地球正在遭受着前所 未有的破坏。 在人类的自私与贪欲面前，地球承受着严重的环境灾难。我们把一个满是 创伤的地球交给下一代，我们应该感到惭愧与内疚。一代人的环境意识代 表着这代人的环境质量。 保护环境，人人有责。让我们共同创造一片蔚蓝的天空、一方清澈的水、 一片净土、一个语花香的未来。
Can you give some names of the planet in our solar system?
Earth，Mercury， Jupiter，Venus金星， Neptune，Uranus， Mars火星， Saturn， Pluto
They are named with the name of Gods in Roman Mythology.
3.Chart Completion
• Part Division of the Text
Part 1 Lines 1 — 10 Main Idea
The satellite landed on Earth has been sending back signals and photographs.
请爱护我们共同的家园！
全球的陆地可以分为七大洲:亚洲,非洲,欧洲,物，在全球生物多样性中占有重要地位。
但是近些年来，由于工业化污染的日益严重，
环境恶化速度在加快，
现代战争科技日趋先进，但带来的污染也是不可估量的。
核污染在当今已是不可避免，未来会怎样，我们都很茫然。
Is There Life on Earth is a humorous fiction, as well as a satire(讽刺文学).
地球上的生活与太空有什么不同英语作文
地球上的生活与太空有什么不同英语作文Life on Earth and in Space: A Comparative ExplorationThe Earth, our home planet, has long been the stage upon which humanity has played out its existence. From the bustling cities to the serene wilderness, the diversity of life and environments found on this world is truly astounding. However, as humanity has ventured beyond the confines of our planet, a new frontier has emerged - the realm of space exploration. The experience of living and working in the vastness of the cosmos presents a stark contrast to the familiar conditions we take for granted on Earth. In this essay, we will delve into the key differences between life on Earth and in the unforgiving environment of space.One of the most fundamental distinctions lies in the presence and nature of gravity. On Earth, we are subject to the constant pull of our planet's gravitational field, which shapes the very nature of our existence. This force dictates the way we move, the way we perceive our surroundings, and even the way our bodies function. From the effortless act of standing upright to the ability to freely navigate ourthree-dimensional world, gravity is an ever-present force that we have adapted to over the course of our evolution.In stark contrast, the microgravity environment of space presents a radically different set of challenges. Without the familiar pull of gravity, the human body undergoes a series of physiological changes that can have profound implications. Muscles and bones, no longer required to support the body's weight, begin to atrophy, leading to a loss of strength and density. The circulatory system must adapt to the lack of gravitational forces, causing fluids to shift and redistribute within the body. Even the sensory organs, such as the inner ear, struggle to maintain their equilibrium, leading to disorientation and motion sickness.These physical challenges are further compounded by the psychological impact of living in a weightless environment. The absence of up and down, the lack of a stable reference point, and the confinement of spacecraft can all contribute to a sense of disorientation and isolation. Astronauts must learn to adapt to these unfamiliar conditions, developing new strategies for performing even the most basic tasks, such as sleeping, eating, and personal hygiene.Another significant difference between life on Earth and in space is the exposure to the harsh realities of the cosmic environment. While the Earth's atmosphere and magnetic field provide a protectiveshield against the harmful radiation and cosmic particles that permeate space, astronauts must contend with these dangers on a constant basis. Solar flares, cosmic rays, and other forms of radiation pose a serious threat to their health, increasing the risk of cancer and other long-term health problems.In addition, the vacuum of space presents its own unique challenges. Without the atmospheric pressure and oxygen-rich environment that we take for granted on Earth, astronauts must rely on specialized life support systems to survive. The slightest breach in their protective equipment could lead to catastrophic consequences, as the lack of air pressure would cause their bodies to rapidly decompress, with potentially fatal results.Furthermore, the vast distances and isolation of space can have a profound impact on the psychological well-being of astronauts. Separated from their loved ones and the familiar comforts of Earth, they must learn to cope with the loneliness and confinement of living in a small, enclosed spacecraft for extended periods. The need to maintain constant communication with mission control and the limited opportunities for social interaction can take a toll on their mental health, leading to issues such as depression, anxiety, and cognitive impairment.Despite these challenges, the experience of living and working inspace also offers unique opportunities and perspectives. Astronauts are afforded a vantage point that few on Earth can ever imagine, allowing them to gaze upon our planet from a distance and gain a profound appreciation for the fragility and beauty of our home. This "overview effect," as it is often called, can lead to a deeper understanding of our place in the universe and a renewed commitment to environmental stewardship.Furthermore, the microgravity environment of space provides a unique laboratory for scientific research, enabling experiments and observations that would be impossible to conduct on Earth. From the study of fluid dynamics and materials science to the exploration of the origins of the universe, the insights gained from space-based research have the potential to revolutionize our understanding of the world around us.In conclusion, the differences between life on Earth and in space are vast and profound. While the familiar pull of gravity, the protective embrace of our atmosphere, and the comfort of our terrestrial environments are essential to our well-being, the challenges and opportunities presented by the cosmic frontier offer a tantalizing glimpse into the future of human exploration and discovery. As we continue to push the boundaries of our understanding and our capabilities, the lessons learned from life in space will undoubtedly shape the way we perceive and engage with our own planet,ultimately leading to a deeper appreciation for the fragile and wondrous world we call home.。
省纸打印版：法国 纪录片《家园》(Home) 中英字幕
请听我说1.Listen to me, please.你跟我一样，是智人2.You're like me, a Homo sapiens.一个有智慧的人3.A wise human.生命是宇宙的奇迹4.Life, a miracle in the universe,出现于约四十亿年前5.appeared around four billion years ago,而我们人类只有二十万年历史6.and we humans only 200,000 years ago.但是我们却破坏了7.Yet we have succeeded in disrupting the balance...地球生命赖以生存的平衡8.that is so essential to life on Earth. 请细听这个不寻常的的故事，你的故事9.Listen carefully to this extraordinary story, which is yours,然后决定你应该做什么10.and decide what you want to do with it.这是我们的起源的轨迹11.These are traces of our origins.最初，我们的星球不过是一个浑沌的火球12.At the beginning, our planet was no more than a chaos of fire,伴随它的恒星--太阳诞生而形成的13.formed in the wake of its star, the sun.一团粘聚的尘埃颗粒14.A cloud of agglutinated dust particles,就像宇宙里面许多类似的星云15.similar to so many similar clusters in the universe.然而生命的奇迹就在此诞生16.Yet this was where the miracle of life occurred.今天，我们的生命17.Today, life- our life-是地球上无数生物形成的生命链中的一环18.is just a link in a chain of innumerable living beings...在近40亿年里，这些生物被彼此继承取代19.that have succeeded one another on Earth over nearly four billion years. 即使到了今天，新的火山继续改变我们的景观20.And even today, new volcanoes continue to sculpt our landscapes.它们让我们目睹了盘古初开时地球的样子21.They offer a glimpse of what our Earth was like at its birth熔石从深处涌出22.molten rock surging from the depths,开始凝固，裂开23.solidifying, cracking,冒着泡，或摊开形成薄的外壳24.blistering or spreading in a thin crust,然后再休眠一段时间25.before fabling dormant for a time. 这些从地球内部吐出缭绕的烟圈26.These wreaths of smoke curlingfrom the bowels of the Earth...是地球原始大气层的见证27.bear witness to the Earth's originalatmosphere.一个没有氧气的大气层28.An atmosphere devoid of oxygen.稠密的大气层，充满水蒸气和二氧化碳29.A dense atmosphere, thick withwater vapor,30.full of carbon dioxide.一个熔炉31.A furnace.因为有水，地球有了一个与众不同的未来32.But the Earth had an exceptionalfuture, offered to it by water.地球与太阳之间的距离适中不太远，不太近33.At the right distance from thesun—not too far, not too near因此地球上的水能够处于液体状态34.the Earth was able to conservewater in liquid form.水蒸气凝结后形成滂沱大雨降落在地球上35.Water vapor condensed and fell intorrential downpours on Earth,河流出现了36.and rivers appeared.河流改变了地球表面37.The rivers shaped the surface ofthe Earth,刻削着河道38.cutting their channels,并冲刷出山谷39.furrowing out valleys.它们流向地球上最低洼的地方形成海洋40.They ran toward the lowest placeson the globe to form the oceans.水溶解了岩石的矿物质41.They tore minerals from the rocks,渐渐的，海洋中的淡水42.and gradually the freshwater ofthe oceans...变成了咸水43.became heavy with salt.水是生命必需的液体44.Water is a vital liquid.它灌溉了这些广阔的不毛之地45.It irrigated these sterile expanses.水流就像人体的血管46.The paths it traced are like theveins of a body,树木的枝丫，是让大地苏醒的液体导管47.the branches of a tree, the vesselsof the sap that it brought to the Earth.40亿年后48.Nearly four billion years later,地球上的某些地方还能找到这样的艺术创作49.somewhere on Earth can still befound these works of art,火山灰混合着来自冰岛冰川的水50.left by the volcanoes' ash, mixedwith water from Iceland's glaciers.就是它们，物质和水51.There they are- matter and water,水和物质52.water and matter-软硬组合，这对地球上所有生物都是至关重要的53.soft and hard combined, thecrucial alliance shared by everylife-form on our planet.金属矿物元素比地球还要古老54.Minerals and metals are evenolder than the Earth.它们是星尘55.They are stardust.它们让地球五彩斑斓56.They provide the Earth's colors.红色是铁，黑色是碳57.Red from iron, black from carbon,蓝色是铜，黄色则是硫58.blue from copper, yellow fromsulfur.我们来自什么哪里？59.Where do we come from?生命火花从哪里迸发？60.Where did life first spark intobeing?一个时光奇迹61.A miracle of time,地球上的温泉仍然有原始的生命存活62.primitive life-forms still exist inthe globe's hot springs.它们赋予温泉颜色63.They give them their colors.它们叫做“古细菌”64.They're called archaeobacteria.它们都依靠地球热能生存65.They all feed off the Earth's heat除了蓝细菌，或是蓝绿藻以外66.all except the cyanobacteria, orblue-green algae.只有它们可以向着太阳来吸取其能量67.They alone have the capacity toturn to the sun to capture its energy.它们是古今所有植种的最重要的祖先68.They are a vital ancestor of allyesterday's and today's plant species.这些微小的细菌69.These tiny bacteria...及其数以亿计的后代70.and their billions of descendants...改变了地球的命运71.changed the destiny of our planet.是它们改造了地球的大气层72.They transformed its atmosphere.毒害大气层的碳去了哪里？73.What happened to the carbon thatpoisoned the atmosphere?它还存在，只是被“囚禁”在地壳74.It's still here, imprisoned in theEarth's crust.想要了解地球历史的这一篇章75.We can read this chapter of theEarth's history...卡罗拉多大峡谷的峭壁是最好的选择76.nowhere better than on the wallsof Colorado's Grand Canyon.它们展现了地球近20亿年的历史77.They reveal nearby two billionyears of the Earth's history.大峡谷曾经是一个聚居着微生物的海洋78.Once upon a time, the GrandCanyon was a sea inhabited bymicroorganisms.它们汲取从大气层溶解到海洋里的碳79.They grew their shells by tappinginto carbon from the atmosphere...并长出外壳80.dissolved in the ocean.它们死后81.When they died, the shells sank... 外壳沉到海床堆叠起来82.and accumulated on the sealed.这些地层就是它们无数的外壳构成的83.These strata are the product of those billions and billions of shells.因为有了它们，碳从大气层中排出84.Thanks to them, the carbon drained from the atmosphere,其他生物才能得以发展85.and other life-forms could develop. 生命改变了大气层86.It is life that altered the atmosphere.植物靠太阳能存活87.Plant life fed off the sun's energy, 这能量使植物分离水分子88.which enabled it to break apart the water molecule...并释放出来氧气89.and take the oxygen.空气因而充满氧气90.And oxygen filled the air.地球的水不断更新循环91.The Earth's water cycle is a process of constant renewal.瀑布，水蒸气，92.Waterfalls, water vapor,云、雨、泉93.clouds, rain, springs,河流、海洋、冰川94.rivers, seas, oceans, glaciers.这个循环从未间断95.The cycle is never broken.地球的水量恒久不变96.There's always the same quantity of water on Earth.历来的生物都喝同样的水97.All the successive species on Earth have drunk the same water.水是令人惊叹的物质98.The astonishing matter that is water.是最不稳定的一种99.One of the most unstable of all.它可以是液态的流水100.It takes a liquid form as running water,气态的蒸汽101.gaseous as vapor...或是固态的冰102.or solid as ice.在西伯利亚，冬季结冰的湖面103.In Siberia, the frozen surfaces of the lakes in winter...蕴含着水在结冰时展现的力量104.contain the traces of the forces that water deploys when it freezes.冰比水轻因而浮于水面105.Lighter than water, the ice floats, 不会沉到湖底106.rather than sinking to the bottom. 它形成御寒的保护罩107.It forms a protective mantle against the cold,冰下的生命可以延续108.under which life can go on.生命的引擎连锁结合109.The engine of life is linkage. 一切都连结起来110.Everything is linked.没有东西是自给自足的111.Nothing is self-sufficient.水和空气不可分割112.Water and air are inseparable,为了地球上的生命而结合113.united in life and for our life onEarth.于是，形成于海洋上的云给陆地带来降雨114.Thus, clouds form over the oceansand bring rain to the landmasses,河流再将水带回海洋115.whose rivers carry water back tothe oceans.分享就是一切116.Sharing is everything.从云层窥望的大片绿色是空气中的氧气117.The green expanse peekingthrough the clouds is the source ofoxygen in the air.七成氧气来自海藻118.Seventy percent of this gas,without which our lungs cannotfunction,这些海藻给海洋表面染上了颜色es from the algae that tint thesurface of the oceans.地球要依赖120.Our Earth relies on a balance...万物各司其职121.in which every being has a role toplay...互相依存的生态平衡122.and exists only through theexistence of another being.一种敏感而脆弱的和谐，极易破碎123.A subtle, fragile harmony that iseasily shattered.于是海藻和贝壳的结合形成了珊瑚124.Thus, corals are born from themarriage of algae and shells.澳大利亚沿海的大堡礁125.The Great Barrier Reef, Off thecoast of Australia,绵延三十五万平方公里126.stretches over350,000 squarekilometers...哺育着一千五百种鱼类，127.and is home to1,500 species offish,四千种软体动物128.4,000 species of mollusks...和四百种珊瑚129.and 400 species of coral.每个海洋的生态平衡都依靠这些珊瑚130.The equilibrium of every oceandepends on these corals.地球计算时间以十亿年计131.The Earth counts time in billionsof years.它花了四十多亿年创造了树木132.It took more than four billionyears for it to make trees.在物种的链条中133.In the chain of species,树木是至高无上的134.trees are a pinnacle,是完美的活的雕塑135.a perfect living sculpture.它们蔑视地心吸力136.Trees defy gravity.它们是唯一永恒地朝向天空的自然元素137.They are the only natural elementin perpetual movement toward the sky.它们的枝叶不疾不徐地向着太阳生长138.They grow unhurriedly toward thesun that nourishes their foliage.它们从微小的古细菌继承了139.They have inherited from thoseminuscule cyanobacteria...吸收光线能量的能力140.the power to capture light'senergy.它们储存并利用此能量141.They store it and feed off it,并使其变成木材和树叶142.turning it into wood and leaves,然后又分解成水，矿物，植物143.which then decompose into amixture of water,和生命物质的混合体144.mineral, vegetable and livingmatter.就这样145.And so, gradually,生命不可或缺的土壤逐渐形成146.the soils that are indispensable tolife are formed.土壤是生物多样性的工厂147.Soils are the factory ofbiodiversity.它们是不断活动的世界148.They are a world of incessantactivity...微生物觅食，挖掘，透气，蜕变149.where microorganisms feed, dig,aerate and transform.它们制造腐植土，在这肥沃的土层上所有生命互相紧扣150.They make the humus, the fertilelayer to which all life on land is linked.地球上的生命我们知道什么？151.What do we know about life onEarth?我们认识多少品种？152.How many species are we awareof?十分之一？还是百分之一？153.A10th of them? A hundredthperhaps?对于它们之间的相互关系我们知道什么？154.What do we know about the bondsthat link them?地球是个奇迹155.The Earth is a miracle.生命仍是个谜156.Life remains a mystery.动物的家族得以形成157.Families of animals form,至今仍存的习惯和仪式使它们凝聚158.united by customs and rituals thatsurvive today.有些适应了环境159.Some adapt to the nature of theirpasture,有些是环境适应它们160.and their pasture adapts to them.双方都受益161.And both gain.动物得到食物，而树木能够开花结果162.The animal sates its hunger, andthe tree can blossom again.在地球上生命的伟大的历险中163.In the great adventure of life on Earth,每种生物各司其职164.every species has a role to play,各有其位165.every species has its place.没有多余或有害166.None is futile or harmful.它们互相抵消167.They all balance out.然后你们168.And that's where you,这些聪明的人类169.Homo sapiens- "wise human'-进入剧情170.enter the story.你们得益于171.You benefit from a fabulous...地球四十亿年的遗产172.four-billion-year-old legacy bequeathed by the Earth.你们只有二十万年历史173.You're only 200,000 years old,但你们已经改变了世界的面貌174.but you have changed the face of the world.尽管你们脆弱175.Despite your vulnerability,但你们占据了所有的栖息地176.you have taken possession of every habitat...征服了所有土地177.and conquered swaths of territory...之前任何生物都未曾做过178.like no other species before you.经过十八万年的游牧岁月179.After180,000 nomadic years,气候变得温和，人类开始定居下来180.and thanks to a more clement climate, humans settled down.他们不再依靠打猎为生181.They no longer depended on hunting for survival.他们定居于充满渔猎182.They chose to live in wet environments...和野生植物的潮湿环境183.that abounded in fish, game and wild plants.这里土地，水和生命结合184.There, where land, water and life combine.人类的天赋让他们发明了独木舟185.Human genius inspired them to build canoes,用于开拓新的视野186.an invention that opened up new horizons...人类变成了航海家187.and turned humans into navigators.即使今天，大部分人类188.Even today, the majority of humankind...都居住在大陆的海岸线189.lives on the continents' coastlines... 或是河边和湖畔190.or the banks of rivers and lakes. 最初的城镇出现在6000多年前191.The first towns grew up less than600 years ago.这是人类历史的一大步192.It was a considerable leap inhuman history.为什么呢？因为这能使人类更容易的保护自己193.Why towns? Because they allowedhumans to defend themselves moreeasily.他们变成了社会人194.They became social beings,在一起分享他们的知识和手艺195.meeting and sharing knowledgeand crafts,融合他们的共性和不同196.blending their similarities anddifferences.简而言之，他们文明化了197.In a word, they became civilized.但他们可用的能量只是双臂198.But the only energy at theirdisposal was provided by nature...和大自然赋予的东西199.and the strength of their bodies.这是人类数千年来的故事200.It was the story of humankind forthousands of years.也是现今四分之一人类201.It still is for one person in four-即十五亿人的故事202.over one and a half billion humanbeings-比富裕国家人口的总和还多203.more than the combinedpopulation of all the wealthy nations.他们只从地球获取必须的用品204.Taking from the Earth only thestrictly necessary.很长一段时间，人类和地球的关系205.For a long time, the relationshipbetween humans and the planet...平衡对等206.was evenly balanced.很长一段时间，经济看起来是自然公正的联盟207.For a long time, the economyseemed like a natural and equitablealliance.但人类寿命短暂，艰苦劳动大行其道208.But life expectancy is short, andhard labor takes its toll.大自然的不可预知加重日常负担209.The uncertainties of nature weighon daily life.教育是罕有特权cation is a rare privilege.子女是家庭唯一资产211.Children are a family's only asset,每双手212.as long as every extra pair ofhands...对家庭的生存都要作出贡献213.is a necessary contribution to itssubsistence.地球为我们提供食物和衣物214.The Earth feeds people, clothesthem...以及日常所需215.and provides for their daily needs.一切来自地球216.Everything comes from the Earth.城镇改变人类本质和命运217.Towns change humanity's nature,as well as its destiny.农夫变成了工匠、商人和小贩218.The farmer becomes a craftsman,trader or peddler.农夫收获，城镇居民购买，或是物物交换219.What the Earth gives the farmer,the city dweller buys, sells or barters.商品交易220.Goods change hands,伴随思想交流221.along with ideas.人类的天份在于经常洞悉自已的弱点222.Humanity's genius is to havealways had a sense of its weakness.他们很想扩张领土223.Humans tried to extend thefrontiers of their territory,但明白自身局限224.but they knew their limits.大自然不曾赋予他们的能量和气力225.The physical energy and strengthwith which nature had not endowedthem...他们在动物身上找到，并驯养它们为己服务226.was found in the animals theydomesticated to serve them.空着肚子怎去征服世界？227.But how can you conquer theworld on an empty stomach?农业的发明228.The invention of agriculture...彻底改变了到处觅食的野兽本质229.transformed the future of the wildanimals scavenging for food...成为真正的人230.that were humankind.农业改写了人类历史231.Agriculture turned their history onend.农业是人类的第一场伟大革命232.Agriculture was their first greatrevolution.八千至一万年前开始233.Developed barely8,000 to10,000years ago,农业改变了人类与自然的关系234.it changed their relationship tonature.它终结了人类不稳定的狩猎和采集时代235.It brought an end to theuncertainty of hunting and gathering.第一次有了盈余236.It resulted in the first surpluses...这催生了城市和文明237.and gave birth to cities andcivilizations.为了农业生产238.For their agriculture,人类利用动物或植物的能量239.humans harnessed the energy ofanimal species and plant life,并从中受益240.from which they at last extractedthe profits.数千年艰苦觅食的记忆逐渐淡忘241.The memory of thousands of yearsscrabbling for food faded.他们学会将谷类适应242.They learned to adapt the grains that are the yeast of life...不同的土壤和气候243.to different soils and climates.他们学会增加农作物的收成和种类244.They learned to increase the yield and multiply the number of varieties.像地球上所有动物245.Like every species on Earth,人类每天的首要任务246.the principal daily concern of all humans...是喂饱自已和家人247.is to feed themselves and their family.当土瘠水稀的时候248.When the soil is less generous and water becomes scarce,人类要为一点干燥土地249.humans deploy prodigious efforts to mark a few arid acres...而拼命劳作250.with the imprint of their labor.人类以极大的耐性和专注去模塑土地251.Humans shaped the land with the patience and devotion that the Earth demands,近乎祭神仪式般不停地重复252.in an almost sacrificial ritual performed over and over.农业仍然是世界上最普遍的职业253.Agriculture is still the world's most widespread occupation.一半人类仍在耕种土地254.Half of humankind tills the soil,超过四分之三仍是手工操作255.over three-quarters of them by hand.农业像传统般一代接一代256.Agriculture is like a tradition handed down...有血有汗地薪火相传257.from generation to generation in sweat, graft and toil,因为它是人类生存的先决条件258.because for humanity it is a prerequisite of survival.人类依赖人力日久259.But after relying on muscle power for so long,开始发掘地球深处的能量260.humankind found a way to tap into the energy buried deep in the Earth.这些火焰也来自植物261.These flames are also from plants. 一束阳光262.A pocket of sunlight.纯粹的能量，太阳量263.Pure energy—the energy of the sun于一亿年前被数以百万计的树木264.captured over millions of years by millions of plants...俘虏了超过数百万年265.more than a hundred million years ago.那是煤，是天然气266.It's coal. It's gas.最重要的是石油267.And above all, it's oil.这束阳光把人类从辛劳的耕种解放出来268.And this pocket of sunlight freedhumans from their toil on the land.石油令人类解除了时间的束缚269.With oil began the era of humanswho break free of the shackles of time.石油令一部分人得享从未有过的舒适270.With oil, some of us acquiredunprecedented comforts.五十年里，仅仅一代人的时间271.And in50 years, in a singlelifetime,地球发生根本性的改变272.the Earth has been more radicallychanged...是前人从未做过的273.than by all previous generations ofhumanity.越来越快274.Faster and faster.过去六十年，人类人口倍增275.In the last60 years, the Earth'spopulation has almost tripled,超过二十亿人移居城市276.and over two billion people havemoved to the cities.越来越快277.Faster and faster.深圳四十年前只是偏僻渔村278.Shenzhen, in China, with itshundreds of skyscrapers and millions ofinhabitants,现在拥有数以百计的摩天大楼和数百万人口279.was just a small fishing villagebarely 40 years ago.越来越快280.Faster and faster.二十年来281.In Shanghai, 3,000 towers andskyscrapers...上海建了三千座高楼大厦282.have been built in 20 years.另有数百座正在建设中283.Hundreds more are underconstruction.今天，地球上七十亿人口有一半住在城市284.Today, over half of the world'sseven billion inhabitants live in cities.纽约，世界上第一个超级城市285.New York. The world's firstmegalopolis...是人类无止境地286.is the symbol of the exploitation ofthe energy...剥削地球资源的像征287.the Earth supplies to humangenius.数百万移民的人力资源288.The manpower of millions ofimmigrants,煤的能量289.the energy of coal,及无约束的石油力量290.the unbridled power of oil.电的出现发明了电梯291.Electricity resulted in theinvention of elevators,而电梯使得摩天大厦成为可能292.which in turn permitted theinvention of skyscrapers.纽约在全球经济排名中位列16293.New York ranks as the16th-largest economy in the world.美国最先发现和开发利用294.America was the first to discover,exploit and harness...珍贵而具革命性的能量“黑金”295.the phenomenal revolutionarypower of black gold.借助它296.With its help,农夫变成了农业企业家297.a country of farmers became acountry of agricultural industrialists.机器取代人力298.Machines replaced men.一升石油等于299.A liter of oil generates as muchenergy...一百双手在24小时产生的能量300.as 100 pairs of hands in 24 hours,但在全球只有3%的农民使用拖拉机301.but worldwide only three percentof farmers have use of a tractor.尽管如此，他们的粮食产出还是支配着地球302.Nonetheless, their outputdominates the planet.美国只剩下三百万农民303.In the United States, only threemillion farmers are left.他们出产的谷物可以养活二十亿人口304.They produce enough grain to feedtwo billion people.但大部分谷物并非用作食粮305.But most of that grain is not usedto feed people.就像其他工业国306.Here, and in all otherindustrialized nations,谷物用来喂牲口或作生化燃料307.it's transformed into livestock feedor biofuels.这束阳光的能量308.The pocket of sunshine's energy...赶走了令土地干旱的幽灵309.chased away the specter ofdrought that stalked farmland.所有泉水都用于农业310.No spring escapes the demands ofagriculture,它占人类水消耗量的70%311.which accounts for70% ofhumanity's water consumption.大自然的一切都互相连系312.In nature, everything is linked.耕地的拓张和单一品种的种植313.The expansion of cultivated landand single-crop farming...增加了害虫的肆虐314.encouraged the development ofparasites.石油化工革命带来的杀虫剂315.Pesticides, another gift of thepetrochemical revolution,把它们杀光316.exterminated them.农作欠收和饥荒成为邀远回忆317.Bad harvests and famine became adistant memory.眼前最头痛是318.The biggest headache now...如何处理现代农业带来的残留319.was what to do with the surpluses engendered by modern agriculture.有毒的杀虫剂渗进空气320.But toxic pesticides seeped into the air,泥土、动植物、河流和海洋321.soil, plants, animals, rivers and oceans.它们入侵一切生命322.They penetrated the heart of cells...赖以生存的细胞核心323.similar to the mother cell that is shared by all forms of life.它们对免于饥饿的人类有害吗？324.Are they harmful to the humans that they released from hunger?这些穿着黄色保护衣物的农夫325.These farmers, in their yellow protective suits,可能有更好的主意326.probably have a good idea.新兴农业免除了对土壤和季节的依赖327.The new agriculture abolished the dependence on soils and seasons.肥料令小片土地328.Fertilizers produced unprecedented results...出产前所未见的丰富收成329.on plots of land thus far ignored. 适应了土地和气候的谷物330.Crops adapted to soils and climates...被产量高和易于运输的品种所取代331.gave way to the most productive varieties and the easiest to transport.于是在上一世纪332.And so, in the last century,农民在过去数千年培育的333.three-quarters of the varieties developed by farmers over thousands of years...四分之三的品种绝种334.have been wiped out.极目所见，下施肥料，上覆塑料335.As far as the eye can see, fertilizer below, plastic on top.西班牙的艾美利亚温室336.The greenhouses of Almeria in Spain...是欧洲的菜园337.are Europe's vegetable garden.大批形状整齐的蔬菜338.A city of uniformly sized vegetables...每天等候数以百计的卡车339.waits every day for the hundreds of trucks...把它们运送到欧洲大陆的超级市场340.that will take them to the continent's supermarkets.国家越发展341.The more a country develops,国民对肉类的需求就越大342.the more meat its inhabitants consume.不依靠集中饲养式牛场343.How can growing worldwide demand be satisfied...如何满足全球日益增长的需求344.without recourse to concentration camp-style cattle farms? 越来越快345.Faster and faster.就像家畜一生都不会见到牧场346.Like the life cycle of livestockwhich may never see a meadow,比动物生长更快的肉类生产成为日常程序347.manufacturing meat faster thanthe animal has become a daily routine.被数百万牛践踏的辽阔饲场348.In these vast food lots, trampled bymillions of cattle,寸草不生349.not a blade of grass grows.一队队卡车从全国各地运来350.A fleet of trucks from every cornerof the country...数以吨计的谷物，黄豆和351.brings in tons of grain, soy meal...丰富蛋白质的饲料最终变成一吨吨的肉352.and protein-rich granules that willbecome tons of meat.结果是生产一公斤马铃薯353.The result is that it takes 100 litersof water...要一百公升水354.to produce one kilogram ofpotatoes,一公斤米要四千公升水355.4,000 for one kilo of rice...而一公斤牛肉要一万三千公升水356.and 13,000 for one kilo of beef.还不算在生产和运输过程被耗掉的石油357.Not to mention the oil guzzled inthe production process and transport.我们的农业成了石油推动型358.Our agriculture has becomeoil-powered.它能养活地球上双倍的人口359.It feeds twice as many humans onEarth...但多元性被标准化取代360.but has replaced diversity withstandardization.它让我们享受到梦中才有的舒适361.It has offered many of us comfortswe could only dream of,但却使我们的生活方式完全依赖石油362.but it makes our way of life totallydependent on oil.这是新的时间观念363.This is the new measure of time.我们的时钟随着那364.Our world's clock now beats to therhythm...永不言倦的阳光机器的节奏365.of these indefatigable machines...一起摆动366.tapping into the pocket of sunlight.它们的规律性让我们安心367.Their regularity reassures us.极小的间断都会引发混乱368.The tiniest hiccup throws us intodisarray.整个地球都注意到了我们369.The whole planet is attentive tothese metronomes...寄托希望和幻想的节拍器370.of our hopes and illusions.同样的希望和幻想随着我们的需求371.The same hopes and illusions thatproliferate along with our needs,以及越来越难以满足的欲望和浪费而增加372.increasingly insatiable desires andprofligacy.我们知道廉价石油时代即将终结373.We know that the end of cheap oilis imminent,但我们拒绝相信374.but we refuse to believe it.对大多数人来说，美国梦体现在一个传奇的名字上：375.For many of us, the Americandream is embodied by a legendaryname:洛杉矶376.Los Angeles.在这个方圆一百公里的城市377.In this city that stretches over100kilometers,汽车的数量几乎与人口相等378.the number of cars is almost equalto the number of inhabitants.这里，晚上是能源卖力表演的时该379.Here, energy puts on a fantasticshow every night.白天不过是夜晚的苍白反映380.The days seem to be no more thanthe pale reflection of nights...晚上的城市变成闪烁星空381.that turn the city into a starry sky.越来越快382.Faster and faster.距离不再以英哩度量而是多少分钟车程383.Distances are no longer counted inmiles but in minutes.汽车重塑郊区面貌，每个房子都好像城堡般384.The automobile shapes newsuburbs where every home is a castle,跟令人窒息的市中心保持安全距离385.a safe distance from theasphyxiated city centers,一排排整齐的房子拥挤在死胡同四周386.and where neat rows of houseshuddle round dead-end streets.少数发达国家的模式387.The model of a lucky fewcountries...通过遍及全球的电视节目388.has become a universal dream,已变成了普遍梦想389.preached by televisions all over theworld.即使在北京390.Even here in Beijing,这些模仿，抄袭和复制391.it is cloned, copied andreproduced...千篇一律的房子已把古塔从地图上抹去了392.in these formatted houses thathave wiped pagodas off the map.汽车成为舒适和进步的象征393.The automobile has become thesymbol of comfort and progress.如果每个社会都跟随这个模式394.If this model were followed byevery society,今天地球不会只有九亿辆汽车395.the planet wouldn't have900million vehicles, as it does today,而是五十亿396.but five billion.越来越快397.Faster and faster.世界越发展，对能源的渴求就更高398.The more the world develops, the greater its thirst for energy.到处都是挖钻矿物的机器399.Everywhere, machines dig, bore and rip from the Earth...把盘古初开时埋在地下的星星挖出来400.the pieces of stars buried in its depths since its creation:矿物401.minerals.未来二十年人类从地球开采的矿物402.In the next 20 years, more ore will be extracted from the Earth...比人类历史上的总数都要多403.than in the whole of humanity's history.由于垄断404.As a privilege of power,80%开采所得财富405.80% of this mineral wealth...只由20%的人口分享406.is consumed by 20% of the world's population.到本世纪末407.Before the end of this century,由于过份开采矿产，人类将会耗尽地球上的大部分资源408.excessive mining will have exhausted nearly all the planet's reserves.越来越快409.Faster and faster.造船厂大量制造油轮410.Shipyards churn out oil tankers, 货柜船，煤气运输船411.container ships and gas tankers... 以应付世界性工业生产的需求412.to cater for the demands of globalized industrial production.大部分消费品要千里迢迢地413.Most consumer goods travel thousands of kilometers...从产地运到消费地414.from the country of production to the country of consumption.自1950年至今，国际贸易总量415.Since1950, the volume of international trade...增长了二十倍416.has increased 20 times over.90%的贸易在海上进行417.Ninety percent of trade goes by sea.每年多达五亿的货柜418.500 million containers are transported every year,被运往主要的消费地区419.headed for the world's major hubs of consumption,例如迪拜420.such as Dubai.迪拜是世界上最大的建筑工地之一421.Dubai is one of the biggest construction sites in the world一个将不可能变成可能的国家422.a country where the impossible becomes possible.例如在大海中建造人工岛423.Building artificial islands in thesea, for example.迪拜缺乏自然资源424.Dubai has few natural resources,但依靠石油赚的钱，它可以输入数百万吨的原料425.but with the money from oil, it canbring millions of tons of material andpeople...和来自世界各地的人口426.from all over the world.它可以建造大厦丛林，一个比一个高427.It can build forests of skyscrapers,each one taller than the last,甚至在沙漠中建滑雪道428.or even a ski slope in the middle ofthe desert.迪拜没有农田，但可以进口食物429.Dubai has no farmland, but it canimport food.迪拜没有水源430.Dubai has no water,但可以花费大量能源431.but it can afford to expendimmense amounts of energy...淡化海水并修建世界上最高的摩天大楼432.to desalinate seawater and buildthe highest skyscrapers in the world.迪拜阳光充沛但没有太阳能电池板433.Dubai has endless sun but no solarpanels.城市的需求永无止境434.It is the city of more is more,在这里最不着边的梦想也能变成现实435.where the wildest dreams becomereality.迪拜是西方模式的顶峰436.Dubai is a sort of culmination ofthe Western model,它的800米高的图腾式建筑437.with its800-meter high totem tototal modernity...一直让世界惊奇438.that never fails to amaze theworld.过分吗？也许吧439.Excessive? Perhaps.迪拜似乎已作出选择440.Dubai appears to have made itschoice.它恰似全球财富的像征441.It is like the new beacon for all theworld's money.没有任何事物比迪拜更远离大自然442.Nothing seems further removedfrom nature than Dubai,但没有任何事物比迪拜更依赖大自然443.although nothing depends onnature more than Dubai.这城市只不过跟随富裕国家的模式444.The city merely follows the modelof wealthy nations.我们还不明白我们正在耗尽自然资源445.We haven't understood that we'redepleting what nature provides.对海洋世界我们了解什么？446.What do we know of the marineworld, of which we see only the surface,它覆盖了地球四分之三的面积447.and which covers three-quarters ofthe planet?海洋深度仍是个秘密448.The ocean depths remain a secret.海洋中存在的数千物种对我们来说也是一个谜449.They contain thousands of specieswhose existence remains a mystery tous.自1950年起，渔业捕获量增加了5倍450.Since1950, fishing catches haveincreased fivefold,由每年一千八百万吨增至一亿吨451.from 18 to 100 million metric tonsa year.数以千计的加工渔船淘空海洋452.Thousands of factory ships areemptying the oceans.四分之三的渔场已枯竭453.Three-quarters of fishing groundsare exhausted,废弃或是频临废弃454.depleted or in danger of being so.大型鱼类已所剩无几455.Most large fish have been fishedout of existence,因为没有时间繁殖456.since they have no time toreproduce.我们把上苍赋予的生命循环摧毁了457.We are destroying the cycle of alife that was given to us.在海岸线上，到处都是资源耗尽的迹象458.On the coastlines, signs of theexhaustion of stocks abound.第一幕：海洋哺乳动物的栖息地越来越小459.First sign: Colonies of seamammals are getting smaller.海洋沿岸的城市化和污染已让它们变得异常脆弱460.Made vulnerable by urbanizationof the coasts and pollution,现在，它们又要面对一个新的威胁：饥荒461.they now face a new threat:famine.它们完全竞争不过工业化的捕鱼船队462.In their unequal battle againstindustrial fishing fleets,无法获得足够的食物哺育后代463.they can't find enough fish to feedtheir young.第二幕：464.Second sign:海鸟为了觅食而越飞越远465.Seabirds must fly ever greaterdistances to find food.按照现在的速度，所有的鱼类资源面临枯竭的危险466.At the current rate, all fish stocksare threatened with exhaustion.在达喀尔，传统的网具捕鱼在很久以前就很发达467.In Dakar, traditional net fishingboomed in the years of plenty,但在今天，鱼类正在减少468.but today, fish stocks aredwindling.五分之一的人以鱼为主食469.Fish is the staple diet of one in fivehumans.我们能想象难以置信的未来吗？470.Can we envision theinconceivable?。
地球上的生物英语作文
地球上的生物英语作文Title: The Diversity of Life on Earth。
Life on Earth is incredibly diverse, encompassing an astonishing array of organisms, from microscopic bacteriato towering sequoia trees. This diversity is not only fascinating but also essential for the functioning of ecosystems and the sustenance of life on our planet.At the heart of Earth's biodiversity are the millionsof species that inhabit various ecosystems across the globe. These species differ not only in their appearances but also in their behaviors, life cycles, and ecological roles. From the majestic African elephant to the tiny yet resilient tardigrade, each organism contributes to the intricate webof life that supports our planet.One of the most remarkable aspects of Earth'sbiodiversity is the adaptability of living organisms. Over billions of years, life has evolved to thrive in diverseenvironments, from scorching deserts to frigid polar regions. This adaptability is evident in the myriad of species that have developed unique adaptations to survivein their respective habitats. For example, camels have evolved specialized features such as humps to store fat reserves and conserve water, allowing them to survive in arid desert conditions.Furthermore, the interconnectedness of species within ecosystems highlights the delicate balance that sustains life on Earth. Each organism plays a vital role in its ecosystem, whether as a predator, prey, or decomposer. For instance, apex predators such as wolves help regulate prey populations, preventing overgrazing and maintaining the health of plant communities. Similarly, decomposers such as fungi and bacteria break down organic matter, recycling nutrients and enriching soil fertility.In addition to their ecological significance, many species also hold cultural and economic value for human societies. Indigenous cultures around the world have long relied on traditional knowledge of local flora and faunafor food, medicine, and spiritual practices. Furthermore, countless industries, such as agriculture, forestry, and pharmaceuticals, depend on biodiversity for resources and innovation.However, despite the intrinsic value of Earth's biodiversity, human activities have significantly threatened many species and ecosystems. Deforestation, habitat destruction, pollution, climate change, and overexploitation of natural resources have led to unprecedented rates of species extinction and loss of biodiversity. This loss not only diminishes the beauty and wonder of the natural world but also undermines the resilience of ecosystems and threatens the well-being of future generations.Addressing the biodiversity crisis requires collective action at local, national, and global levels. Conservation efforts must focus on protecting and restoring habitats, implementing sustainable practices, and combating illegal wildlife trade. Furthermore, raising awareness about the importance of biodiversity and promoting environmentaleducation are crucial steps towards fostering a greater appreciation for the natural world and inspiring conservation action.In conclusion, Earth's biodiversity is a testament to the wonders of evolution and the resilience of life. From the depths of the ocean to the heights of the mountains, living organisms have thrived in diverse environments, shaping the world we inhabit today. However, the ongoing loss of biodiversity underscores the urgent need for conservation action to preserve Earth's rich tapestry of life for future generations. As stewards of our planet, it is our responsibility to protect and cherish the precious gift of biodiversity that sustains all life on Earth.。
地球生命共同体 英语作文
地球生命共同体英语作文Title: Building a Shared Community of Life on Earth。
In recent years, the concept of a "Shared Community of Life on Earth" has gained significant traction worldwide, underscoring the interconnectedness and interdependence of all living beings on our planet. This concept advocates for a harmonious coexistence among humans, animals, plants, and the environment, emphasizing mutual respect, cooperation, and sustainability. As we delve deeper into the discourse surrounding this idea, it becomes evident that fostering a shared community of life on Earth is not merely a lofty aspiration but a pressing necessity for the survival and well-being of all species.At the heart of the concept lies the recognition that every organism, regardless of its size or significance, plays a crucial role in maintaining the delicate balance of our planet's ecosystems. From the tiniest microorganism to the mightiest apex predator, each entity contributes to theintricate web of life that sustains us all. Thus,preserving biodiversity and safeguarding the habitats of diverse species are paramount in nurturing a shared community of life on Earth.Moreover, the notion of shared responsibility underscores the need for collective action to address pressing environmental challenges such as climate change, deforestation, pollution, and habitat loss. These issues transcend national borders and require concerted efforts from governments, organizations, communities, andindividuals worldwide. By acknowledging our interconnectedness and assuming responsibility for thewell-being of our planet, we can pave the way for a more sustainable and equitable future.Education also plays a pivotal role in fostering asense of stewardship and reverence for the natural world.By instilling environmental literacy and empathy towards other species from an early age, we can cultivate a generation of global citizens who are committed to preserving and protecting our planet for future generations.Environmental education programs, initiatives, and campaigns are essential tools in raising awareness about the importance of biodiversity conservation and sustainable living practices.Furthermore, promoting sustainable development practices is essential in reconciling human needs with the health of the planet. This entails adopting renewable energy sources, promoting eco-friendly agriculture, implementing waste reduction and recycling measures, and advocating for responsible consumption and production patterns. By embracing sustainability as a guidingprinciple in all aspects of human endeavor, we can minimize our ecological footprint and ensure the long-term viability of our shared community of life on Earth.In addition to environmental considerations, social justice and equity are integral components of building a shared community of life on Earth. Recognizing the interconnectedness of environmental and social issues, we must address underlying inequalities and inequities that exacerbate environmental degradation and threaten the well-being of marginalized communities. Environmental justice initiatives seek to redress these disparities by empowering vulnerable populations and ensuring their voices are heard in decision-making processes that affect their lives and livelihoods.In conclusion, the concept of a Shared Community ofLife on Earth encapsulates the fundamental interconnectedness of all living beings and the imperative to foster harmony, cooperation, and sustainability among them. By embracing this ethos and taking concrete actions to preserve biodiversity, mitigate climate change, promote sustainable development, and uphold social justice, we can create a more equitable and resilient world for current and future generations. Together, let us strive to build a future where all species thrive in harmony within the intricate tapestry of life on Earth.。
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1104 GEOLOGY FOR ENGINEERSWeek 1, 2011These notes are comprehensive and should be ready like a novel. They incorporate only the first week of lectures and I do not expect you to know all this material. I put it here to show you where science is at present with understanding big questions. Scientific knowledge doubles every 7 years, nothing is set in stone, there is no consensus about anything and the science on a matter is never settled. There is nothing wrong with saying “I don’t know”. What is even more important is to show that the Earth is always changing, ideas are evolving and planet Earth is a fascinating place so don’t depart too early. Future MyUni contributions will only be a couple of pages long.Life on EarthSingle-celled lifeThe dominant life form on Earth is bacteria. They, like us, are based on DNA. This means we are related to the bacteria in our gut, on our teeth, in our faeces and those that can kill us. Bacteria, mammals, reptiles, amphibians, plants and all life are children of DNA. We all have the same sort of cells and hence have a common origin1. Some 90% of the cells in a human body are bacterial. Bacteria account for 15% of the weight of the human body. The greatest biomass on Earth is bacteria. They thrive in both hostile and benign environments. Bacteria can do many things we can’t. For example, they can eat rock 3 km beneath our feet2 and 5 km beneath the ocean floor3,4.These single-celled organisms exist in clouds, ice, hot springs, salt, soil, water, cracks in rocks and every conceivable environment on Earth. At least half the world’s biomass is below the Earth’s surface5, mainly as extremophile bacteria that can tolerate high pressure, high or low temperatures and extremes of acidity, with or without oxygen6. Bacteria dominate hot, cold, dry, wet, oxygen-rich, oxygen-poor, dark, sunny, acid, alkaline, radioactive, high-pressure and low-pressure environments7,8. Liquid water allows the transfer of nutrients in bacterial cells and it is no coincidence that the first appearance of life on Earth was when there was liquid water on Earth. Bacteria can thrive in environments that normally are toxic to multicellular organisms. After hundreds of1 Gu, X. 1997: The age of the common ancestor of eukaryotes and prokaryotes. Statistical inferences. Molecular Biology and Evolution 14: 861-866.2 Lithautotrophs3 Stevens, T. O. and McKinley, J. P. 1995: Lithautotrophic microbial ecosystems in deep basalt aquifers. Science 270: 450-454.4 Santelli, C. M., Orcutt, B., Banning, E., Bach, W., Moyer, C. L., Sogin, M. L., Staudigel, H. and Edwards, K. J. 2008: Abundance and diversity of microbial life in ocean crust. Nature 453: 653-656.5 McCall, J. 2003: The deep biosphere. Geoscientist 13 (3): 11.6 Jørgensen, B. B. and Boetius, A. 2007: Feast and famine – microbial life in the deep seabed. Nature Reviews Microbiology 5: 770-781.7 Hei, D. J. and Clark, D. S. 1994: Pressure stabilization of proteins from extreme thermophiles. Applied and Environmental Microbiology 60: 932-939.8 Rothschild, L. J. and Mancinelli, R. L. 2001: Life in extreme environments. Nature 409: 1092-1100.millions of years of being trapped in brine, bacteria can be resurrected9. Other bacteria can survive a 25 kV electron beam and resultant high temperatures in a vacuum, which stimulates speculation about extremophiles hitching a ride on meteorites10.Bacteria are the ultimate survivors on planet Earth. The chances of finding modern or fossil life elsewhere in our Solar System are very high because of the resilience of bacteria11 and the appropriate geological settings for bacterial life12,13,14. Modern life may exist on Mars15, Europa16 and Titan17,18 and fossil life may be found on Mars19.Was the rise of life inevitable on this planet? If we ran the story of the Earth again, would life itself again evolve? And if it did, would it evolve with DNA at its crux? Was ammonia the solvent necessary for life, only to be replaced by a better solvent (water)? We need a solvent for delivering chemicals in solution for cells to operate. Did the appearance of life happen just once and then spread across Earth, or did life appear many times, only to be wiped out many times by asteroid impacts? Did RNA evolve to DNA, or have mineral surfaces (iron sulphides, clays) been the site for the biological takeover of non-biological reactions? How quickly did life appear? If life appeared quickly, then there may well have been many occurrences of life elsewhere in the Solar System. Where did the appearance of life happen? Darwin suggested a Sun-warmed pond. Others suggest hot springs, especially in the deep oceans, whereas others suggest cracks deep in rocks. These early steps we do not see in the fossil record because the oldest rocks on Earth are 4200 million years ago (Ma) and ancient rocks have been deformed and heated many times. We see bacteria and archaea extremophiles as the oldest fossils. Were the individual stages in the origin of life (amino acids, nucleic acids, cells) dependent upon long-term changes in the Earth’s environment? Did the origin of life change the9 Vreeland, R. H., Rosenzweig, W. D. and Powers, D. W. 2000: Isolation of a 250 million-year-old halotolerant bacterium from a primary salt crystal. Nature 409: 897-900.10 McKay, D. S., Gibson, E. K., Thomas-Keprta, K. L., Vali, H., Romanek, C. S., Clemett, S. J., Chillier, X.D. F., Maechling, C. M. and Zare, R. N. 1996: Search for past life on Mars: possible relic biogenic activity in Martian meteorite ALH84001. Science 273: 924-930.11 Baross, J. A. and Holden, J. F. 1996: Overview of hyperthermophiles and their heat-shock proteins. Advances in Protein Chemistry 48: 1-35.12 Russell, M. J., Hall, A. J., Cairns-Smith, A. J. and Braterman, P. S. 1988: Submarine hot springs and the origin of life. Nature 336: 117.13 Romanek, C. S., Grady, M. M., Wright, I. P., Mittlefehldt, D. W., Socki, R. A., Pillinger, C. T. and Gibson, Jr, E. K. 1994: Record of fluid interactions on Mars from the meteorite ALH84001. Nature 372: 655-657.14 Russell, M. J., Ingham, J. J., Zedef, V., Maktav, D., Sunar, F., Hall, A. and Fallick, A. 1999: Search for signs of ancient life on Mars: expectations from hydromagnesite microbialites, Salda Lake, Turkey. Journal of the Geological Society, London 156: 869-888.15 Squyres, S. W. and Kasting, J. F. 1994: Early Mars – how warm and how wet? Science 265: 744.16 Jakosky, B. M. and Shock, E. L. 1998: The biological potential of Mars, the early Earth, and Europa. Journal of Geophysical Research 103: 19359.17 Lunine, J. I., Stephenson, D. J. and Yung, Y. L. 1983: Ethane ocean on Titan. Science 222: 1229-1230.18 Brown, R. H., Soderblom, L. A., Soderblom, J. M., Clark, R. N., Jaumann, R., Barnes, W., Sotin, C., Buratti, B., Baines, K. H. and Nicholson, P. D.2008: The identification of liquid ethane in Titan’s Ontario Lacus. Nature 454: 607-610.19 Kirschvink, J. L., Maine, A. T. and Vali, H. 1997: Palaeomagnetic evidence supports a low temperature origin of carbonate in the Martian meteorite ALH84001. Science 275: 1629-1633.environment such that life could never evolve again? At what stage did evolution take over to influence the development of life? Too many questions, not enough answers. Colonies of bacteria are like a huge parallel processing machine, an intelligent machine that does what no computer can do. Bacteria re-engineer their genome to survive in a new hostile environment, which is why they are the longest-running players in the game of evolution. The huge number of bacteria guarantees survival. Bacteria are the only organisms that remain on Earth from the beginning of life before 4000 Ma. Before that, there may have been RNA- or protein-based life20. Planet Earth formed on a Thursday21 at 4567 Ma. By contrast, humans (i.e. Homo sapiens) have only been on Earth for just over 100,000 years.Colonies of fossilised bacteria can still be found, despite the fact that 90% of the ancient rocks once deposited on Earth are now gone. By 3500 Ma we have very clear evidence of bacterial colonies (stromatolites) in Western Australia, Canada and South Africa. Although stromatolites are in the fossil record from 3500 Ma to the present, they reached their zenith at about 1000 Ma. Stromatolites extracted carbon dioxide (CO2) from the atmosphere to secrete carbonate. Stromatolites still exist on Earth but in far more oxygenated conditions (e.g. Shark Bay, Western Australia). This clearly indicates that the first life on Earth (bacteria) is still with us and is the dominant life form on Earth. This again hints that if there is to be life elsewhere in the Universe, we could expect it to be bacterial.The proportion of reduced to oxidised22 carbon in life23 and seawater24 has remained the same since the earliest times on Earth. From this we conclude that the fundamentals of the carbon cycle on Earth were established as early as 4000 Ma25,26. This constant proportion is difficult to reconcile with a faint young Sun that was 30% less luminous at that time27,28. With such a weak Sun, the Earth should have been a snowball until a billion years ago. Some argue that the Earth must have had a huge greenhouse effect at that time29 with an atmospheric CO2 content of 35% to prevent a snowball30 yet this is not in 20 Lazcano, A. 1994: The RNA world, its predecessors, and its descendents. In: Early life on Earth (ed. Bengston, S.), 70-80, Columbia University Press.21 Obviously Thursday, named after Thor (the Norse god of thunder).22 Reduced carbon is biologically-bound carbon, methane and carbon monoxide whereas oxidised carbon is CO2.23 Schidlowski, M., Eichmann, R. and Junge, C. E. 1975: Precambrian sedimentary carbonates: carbon and oxygen geochemistry and implications for the terrestrial oxygen budget. Precambrian Research 2: 1-69.24 Hayes, J. M., Kaplan, I. R. and Wedeking, K. W. 1983: Precambrian organic geochemistry. In: The Earth’s early biosphere: Its origin and evolution (ed. Schopf, J. W.). Princeton University Press.25 Mojzsis, S., Arrhenius, G., McKeegan, K. D., Harrison, T. M., Nutman, A. P. and Friend, C. R. L. 1996: Evidence for life on Earth before 3,800 million years ago. Nature 385: 55-59.26 Veizer, J. 2005: Celestial climate driver: A perspective from four billion years of carbon cycle. Geoscience Canada 32: 13-28.27 Sagan, C. and Mullen, G. 1972: Earth and Mars: Evolution of atmospheres and surface temperatures. Science 177: 52-56.28 Crowley, T. J. and Baum, S. K. 1993: Effect of decreased solar luminosity on late Precambrian ice extent. Journal of Geophysical Research 98: 16723-16732.29 Kasting, J. F. 1993: Early earth’s atmosphere. Science 259: 920-926.accord with ancient limestone deposition and chemistry31. If there were decreased cloud cover32, the Sun’s decreased luminosity would have kept Earth benign with neither ice sheets nor vaporised water33.Although mass extinctions of multicellular life are the normal business of an evolving planet34, bacteria have survived all mass extinctions of complex life on Earth. Contrary to popular belief, there is no such thing as conservation of species. Life evolves, and part of evolution is a regular species turnover by extinction. Nothing can be conserved in a dynamic evolving environment. Extinction is normal. Species conservation is a romantic non-scientific view of planet Earth35.Old 3800 Ma rocks in Greenland that were once gravels, sands and silts have a story to tell. Life appeared when the very heavy rain of large asteroids and comets stopped. These extraterrestrial impacts would have vaporised rocks and water. Calculations show that a 500 km diameter asteroid would vaporise oceans to a depth of 3000 metres. The planet’s surface would have been sterilised. Compared to today, when life appeared there was still a higher frequency of asteroid impacting, the length of the day was shorter, Earth was rotating much faster, the Sun was much dimmer, the atmosphere was much denser, UV light entering Earth was more intense and the sky was orange to brick red. These large impacts reworked the surface of the Earth and were a driving force for the formation of the Earth’s crust36.The first rain on Earth was when the atmosphere was below 100ºC. When this rain hit hot rocks, it would have vaporised. Rain was acid, had no oxygen and attacked the rocks to form thick soils (weathering). Because these soils were chemically reduced, they would have been green, compared to modern oxidised soils that are red-brown, or organic rich soils that are black. The first water on Earth was primarily from volcanic degassing although comets added a small amount. Once the surface of Earth cooled to below 100ºC, there was running water which would have removed soil (erosion) and deposited it as sediment (sedimentation).Seas covered the Earth except for a few flat islands. The seas were acid and hot, and muddy with sediment. These sediments would have hardened to sedimentary rocks and the oldest sedimentary rocks are the most likely place to find clues about the first life on Earth. The planet went from being lifeless to having life. Although there was a faint Sun, the surface of planet Earth could not have been frozen because there is evidence of30 Kasting, J. F. and Ackerman, T. P. 1986: Climatic consequences of very high carbon dioxide levels in the Earth’s early atmosphere. Science 234: 1383-1385.31 Shields, G. and Veizer, J. 2002: Precambrian marine carbonate isotope database. Version 1.1. Geochemistry, Geophysics, Geosystems 3: June 6, 2002, 12p.32 Rossow, W. B., Henderson-Sellers, A. and Weinreich, S. K. 1982: Cloud feed-back: A stabilising effect for the early earth? Science 217: 1245-1247.33 Ou, H.-W. 2001: Possible bounds on the Earth’s surface temperature: From the perspective of conceptual global mean model. Journal of Climate 14: 2976-2988.34 Raup, D. 1979: A kill curve for Phanerozoic marine species. Paleobiology 17: 37-48.35 Raup, D. 1990: Extinction: Bad genes or bad luck. Norton.36 Glikson, A. Y. 1999: Ocean mega-impacts and crustal evolution. Geology 27: 387-390.running water. The chemistry of black smudges in the old gravels of Greenland sediments shows that there was life37 and oxidised uranium in the sediments shows that there was a minute trace of oxygen gas in the atmosphere38.The conclusion is inescapable: we had a fully functioning biosphere at 3800 Ma. Bacteria were anaerobic (i.e. needed no oxygen) although there was a minute trace of oxygen in the atmosphere. The atmospheric gases derived from degassing of the planet by volcanoes39. The atmosphere at that time was dominated by nitrogen, CO2, ammonia,H2O vapour, hydrogen sulphide, argon, helium and hydrogen40,41,42, as it is on many rocky planets and moons. Although carbon cycles have been continually refined43, the presence of a planetary thermostat is the only way that planet Earth has not suffered a runaway greenhouse effect as a result of the Sun emitting more energy over time44. Concepts of the Earth as a self-regulatory planet45 fail because of the input of material from the Sun and the cosmos. For example, some 40,000 tonnes of extraterrestrial material falls each year and much of this contains organic molecules, including amino acids (the building blocks of DNA) 46,47. Amino acids can also be synthesised on Earth in hot springs48,49,50,51,52, by other simple processes53 or at the site of an oceanic impact54. Hence an extraterrestrial origin of life is not necessary.37 Rosing, M. T. 1999: C-13-depleted carbon microparticles in >3700-Ma sea-floor sedimentary rocks from west Greenland. Science 283: 674-676.38 Rosing, M. T. and Frei, R. 2004: U-rich Archaean sea-floor sediments from Greenland – indications of >3700 Ma oxygenic photosynthesis. Earth and Planetary Science Letters 217: 237-244.39 Hunten, D. M. 1993: Atmospheric evolution of the terrestrial planets. Science 259: 915-920.40 Holland, H. D. 1984: The chemical evolution of the atmosphere and oceans. Princeton University Press.41 Cloud, P. 1987: Oasis in space. Norton.42 Kasting, J. F. 1993: Earth’s early atmosphere. Science 259: 920-926.43 Walker, J. C. G., Hays, P. B. and Kasting, J. F. 1981: A negative feedback mechanism for the long-term stabilization of Earth’s surface temperature. Journal of Geophysical Research 86: 9776-9782.44 Sagan, C. and Mullen, G. 1972: Earth and Mars: Evolution of atmospheres and surface temperatures. Science 177: 52-56.45 Lovelock, J. E. 1979: Gaia, a new look at life on Earth. Oxford University Press.46 Chyba, C. F., Thomas, P. J., Brookshaw, L. and Sagan, C. 1990: Cometary delivery of organic molecules to the early earth. Science 249: 366-373.47 Chyba, C. F. and Sagan, C. 1992: Endogenous production, exogenous delivery, and impact-shock synthesis of organic molecules: An inventory for the origins of life. Nature 355: 125-131.48 Miller, S. L. and Bada, J. L. 1988: Submarine hot springs and the origin of life. Nature 334: 609-611.49 Marshall, W. L. 1994: Hydrothermal synthesis of amino acids. Geochimica et Cosmochimica Acta 58: 2099-2106.50 Fox, S. W. 1995: The synthesis of amino acids and the origin of life. Geochimica et Cosmochimica Acta 59: 1213-1214.51 Oro, J. 1994: Early chemical stages in the origin of life. In: Early life on Earth (ed. Bengtson, S.), 48-59. Columbia University Press.52 Nisbit, E. G. 1986: RNA, hydrothermal systems, zeolites and the origin of life. Episodes 9: 83-90.53 Miller, S. L. 1953: A production of amino acids under possible primitive Earth conditions. Science 117: 528-529.54 Furukawa, Y., Sekine, T., Oba, M., Kakegawa and Nakazawa, H. 2009: Biomolecule formation by oceanic impacts on early Earth. Nature Geoscience 2: 62-66.In order to balance the supply of CO2 from a great diversity of natural processes, weathering may be the driving force55,56. Weathering is the process whereby rocks are converted to soil. The popular paradigm was that it is a chemical process involving addition of H2O, oxygen and CO2 to rocks. It is now thought of as a process where the decomposition of rock to soil and the addition of H2O, CO2 and oxygen to soils is driven by bacteria. On ancient Earth, oxygen was not necessary for weathering. A high CO2 world has abundant energetic micro-organisms, abundant runoff and a resultant high rate of chemical weathering. However, land plants have been on Earth for only 10% of time. Before that, there was increased weathering, erosion and sedimentation because there were no land plants to hold soils to the underlying rocks. Chemical weathering (and hence the uptake of H2O and CO2) in a glacial world is slow because of the lack of energetic micro-organisms, heat and acid rain. Atmospheric CO2 then increases.This weathering thermostat regulates planet Earth such that there is no permanent icehouse and no permanent runaway greenhouse. The thermostat is strong enough to create equilibrium although after occasional extreme events57, it took 100,000 years or so for CO2 to reach equilibrium again58. Vostok ice cores in Antarctica show that, despite wild fluctuations in temperature and atmospheric CO2 over 650,000 years, the carbon fluxes must have been in balance to within 1–2%59. Furthermore, ice core records show that atmospheric CO2 increases some 800 years after natural temperature increases. Measurements of modern atmospheric CO2 show that there is a rapid uptake of CO2 in the Northern Hemisphere growing season. The fact that the Earth’s climate has been stable for far longer than the CO2 equilibration time shows that since the first evidence of weathering, erosion and sedimentation at about 3800 Ma, CO2 in the Earth’s atmosphere has essentially been at equilibrium.Over the history of time, volcanoes have been exhaling CO2 into the atmosphere. For the first 4 billion years of Earth history, the CO2 content of the atmosphere has been 3 to 100 times the current CO2 content. We currently have some 700 terrestrial active volcanoes and at least 3.47 million submarine volcanoes. All volcanoes emit CO2, submarine volcanoes emit far more CO2 than terrestrial volcanoes. Mars and the Moon are still leaking out CO2 and CH4 despite a lack of volcanic activity. Life has been extracting CO2 for reefs and shells for billions of years. Cements holding grains together and sediments have also sequestered CO2 over time. As a result, the CO2 of the atmosphere has been decreasing and is near the lowest level it has been in the history of the planet. There was no “tipping” point or runaway greenhouse when CO2 and temperature were high in the past. For billions of years, the Earth’s thermostat has prevented runaway greenhouse or runaway icehouse. Nothing has changed.55 Gaillardet, J., Dupré, P., Louvat, P. and Allègre, C. J. 1999: Global silicate weathering and CO2 consumption rates deduced from the chemistry of the large rivers. Chemical Geology 159: 3-30.56 Royer, D. L., Berner, R. A. and Park, J. 2007: Climate sensitivity constrained by CO2 concentrations overthe past 420 million years. Nature 446: 530-532.57 Such as the Palaeocene-Eocene Thermal Maximum at 55.8 Ma.58 Dickens, G. R., Castillo, M. M. and Walker, J. C. 1997: A blast of gas in the latest Paleocene: Simulating first-order effects of massive dissociation of oceanic methane hydrate. Geology 25: 259-262.59 Zeebe, R. and Caldeira, K. 2008: Close mass balance of long-term carbon fluxes from ice-core CO2 andocean chemistry records. Nature Geoscience 1: 312-315.In the Witwatersrand Basin of South Africa, gold has been mined from 2600 Ma ancient gravels since 1883. In the ancient gravels (conglomerate), rounded pieces of quartz, rock fragments and gold show that there was weathering, removal of weathered material and the deposition of this eroded material as sediment. In this process, there is an interaction of water, air, rocks and life. These conglomerates also contain rounded grains of an iron sulphide (pyrite, fools gold). Today, when the atmosphere has 21% oxygen gas, pyrite is easily oxidised in water to iron oxide and sulphuric acid. If pyrite has tumbled down river systems grinding it to rounded grains that were in contact with air and water, then the atmosphere at 2600 Ma had little (less than 1%) or no oxygen. Furthermore, these conglomerates contain rounded grains of a uranium oxide (uraninite). If there was oxygen in the atmosphere, the uranium would have oxidised and changed from the immobile reduced uranium to the highly mobile oxidised uranium. Because uraninite exists in the Witwatersrand conglomerates, we have a second line of evidence to suggest that there was little or no oxygen in the atmosphere at that time. Similar conglomerates in Brazil and Western Australia show that the global oxygen content of the atmosphere was low at 2600 Ma.At about 2500–2700 Ma, there was a fundamental change to the Earth. Older crust, similar to that which is still present on the Moon, was replaced by a lighter more silica-rich crust. Earth now has a SIAL crust (silica-alumina) which is continental and a SIMA crust (silica-magnesium) which is oceanic. This change in the Earth’s crust is related to thickening of the crust, the lower heat flow and the expelling of very large and very small atoms from the Earth’s mantle. The first validated evidence of plate tectonics is from rocks of this age. Continental evolution via plate tectonics had an influence on the evolution of life.Before 2700 Ma, the continents occupied less than 5% of the surface of Earth. There was a rapid build-up of continents from 2700 to 2500 Ma (5% to 30%) due to an increased rate of plate tectonics. What is amazing is that around that time there was glaciation, a sudden diversification of life, a sudden increase in atmospheric oxygen, rusting of the oceans and the appearance of eukaryotic life60. The unanswered question is: Did this period of very rapid plate tectonics induce a diversification of life? The ocean volumes are clearly fundamental to life. If Earth’s ocean volumes were greater, there would be no continents and Earth would be like Jupiter’s moon Europa, with no land and 100 km deep oceans covered by ice. In this environment, only prokaryotic bacteria can exist. There would be no shallows for limestone formation and no continental weathering for the provision of nutrients for life in the oceans.What if the continents covered 70% of the globe rather than the current 30%? If the continents occupied 70% of the globe, we would expect large and rapid temperature swings because large land areas create very high and very low seasonal temperatures. Large land areas reduce CO2 drawdown because carbonate formation is in oceans and, in land-dominated systems, the opportunity for life to thrive is reduced. If plate tectonics60 Eukaryotic life is a cell with a nucleus within which genetic material is protected whereas prokaryotic life has no cell nucleus.were not operating, then we would have no continents. Where there is too much water, we get deep oceans and there is no natural brake on CO2 build-up. This results in a runaway greenhouse. We remove CO2 from the atmosphere into limestone, a rock that was very rare before 2500 Ma and a rock that has greatly increased in volume over time. This is why the atmospheric CO2 has been decreasing over time and will continue to decrease. As limestone forms mainly in reefs that occur in water less than 6 metres deep, shallow water is essential to stop a runaway greenhouse. Continental weathering brings chemicals to the sea, changes seawater composition and adds nutrients into shallow water. Weathering is a process that consumes acid. The early oceans were acid and only after a long period of weathering could the oceans change from acid to alkaline. Although extremophiles can live in acid water, no shelled animal can live in acid water because its carbonate shell would dissolve. Again, it is continents (formed from plate tectonics) and the resultant weathering that assisted the explosion of life.Our Earth got it right. Without continents it would be too hot because main sequence stars like the Sun increase energy output over time and with too much continental landmass, the CO2 drawdown during weathering would produce permanent glaciation. Other fundamental and probably related processes also took place at this time. Isotopes of oxygen and carbon show that Earth was enjoying an equatorial glaciation61 at around 2400 to 2100 Ma62. Life on Earth almost ceased63. These times of great dearth were interspersed with great bursts of high biological productivity. These bursts of productivity were assisted by high atmospheric CO2, the release of nutrients into the oceans by glacial melt waters and warmer temperatures. Even today we see from satellites that the subtropical oceans contain less biota than the stormy mid-latitude and sub-polar seas which are better supplied with nutrients. Calm oceans and seas have a widespread scarcity of nutrients. There were a number of times in Earth history when the oxygen content of the atmosphere suddenly increased. These were immediately after glaciation. Melt waters bring huge amounts of nutrients to the oceans, stimulating a blossoming of photosynthetic micro-organisms, and these then add oxygen to the atmosphere64,65,66. There was a global period from 2400–2200 Ma when the oceans rusted. All of the world’s major iron ore deposits formed at this time, demonstrating that there was a sudden global increase in oxygen gas in the atmosphere. Furthermore, there was a diversification from single-celled prokaryotic to single-celled more complicated61 Huronian glaciation62 Schopf, J. W. and Klein, C. (eds) 1992: The Proterozoic biosphere: A multidisciplinary study. Cambridge University Press.63 Kopp, R. E., Kirschvink, J. L., Hilburn, I. A. and Nash, C. Z. 2005: The Palaeoproterozoic snowball Earth: a climate disaster triggered by the evolution of oxygenic photosynthesis. Proceedings of the National Academy of Sciences 102: 1131-1136.64 Asmeron, Y., Jacobsen, S. B., Knoll, A. H., Butterfield, N. J. and Sweet, K. 1991: Strontium isotope variations of Neoproterozoic seawater: implications for crustal evolution. Geochimica et Cosmochimica Acta 55: 2883-2894.65 Jacobsen, S. B. and Kaufman, A. J. 1999: The Sr, C and O isotope evolution of Neoproterozoic seawater. Chemical Geology 161: 37-57.66 Higgins, J. A. and Schrag, D. P. 2003: The aftermath of snowball Earth. Geochemistry, Geophysics, Geosystems 4: doi: 10.1029/2002GC000403.。