生态学复习题

Chapter 1# Ecologythe science that treats the spectrum of interrelationships existing between organisms and their environments and among groups of organisms.# speciesa natural group of actually or potentially interbreeding individuals reproductively isolated from other such groups.# Ecosystem ComponentsNonliving parts:energy source, nutrient and water sourceLiving parts:Producer,Consumer,Decomposer# food chainEach pathway that transfers energy from a given source plant or plants through a given series of consumers# standing cropWithin each trophic level or population, the amount of living material at any instant in time# biogeochemical cyclesAmong many of the chemical elements and compounds in ecosystems there is a cycling back and forth between organisms and the physical environment. Such repeated transfers are called biogeochemical cyclesThe most significant cycles: carbon cycle, nitrogen cycle, phosphorus cycles.# nicheniche in ecology is usually defined as the role of an organism in a community.# dominantsThe numerically abundant species in communities# Species diversitya measure that combines into a single figure both the number of species and the distribution of the total number of individuals among the species.# Leibig’s law of the minimum.Each species requires a certain minimum amount of various materials. If the concentrations of these necessities, such as nitrate, fall below the minimum, the species disappears.# Shelford's Law of Tolerancea species' distribution is controlled by the environmental factors for which it has the narrowest tolerance. This law explains why a species is present in some areas, but absent in others. Remember that tolerance has both a lower limit and an upper limit - not enough or too much of a resource will limit a species' ability to survive. When any one of these factors exceeds the tolerance, the species will die out.# ecological succession1.classical model by Clement(1936)Communities are not static units. They change in structure and composition with time. Some tend to change in an orderly fashion until they reach a persistent stage. This orderly process of community change controlled through modification of the physical environment is called2.inhibition model by Egler(1954)In this model, succession is not an orderly predictable process and there is no climatic climax.3.tolerance model by Connel and Slayter (1977), is intermediate between the other two. In this model early colonizing (定居) species are not necessary, and any species can start succession. Community change occurs as species are more tolerant or competitively superior.# Competitionan ecological term referring to the interaction among organisms for a necessary resource that exists in short supply.Competition may be intraspecific or interspecific.Resouece that can be competed: light, food, nutrients, water and space.The competition case:The competitors share the limited sources. In this case both individuals are hampered.One competitor excludes the other. In this case one individual is eliminated.# Competition exclusion principleno two species with the same requirements can coexist in the same place at the same time; that is, complete competitors cannot exist.# Comparison of Terrestrial and Marine EcosystemsPhysical and Chemical Differences: Greater density; Water absorbs light stronger; Gravity difference; Oxygen differencesStructural and Functional Differences: The dominant autotrophs are microscopic plants and the dominant herbivores(copepods) of the sea are also small; The plant of the sea is short-lived; Most marine food chains have about 5 links, whereas terrestrial food chain tend to be shorter, averaging three links; The small herbivores of the seasusually consume the entire plant and can remove the plants completely; The production of organic material is higher in terrestrial ecosystems than in marine, but the efficiency of transfer from first to second trophic levels is higher in marine ecosystems; The trophic level of the sea is blurred.============================================================= ==========Chapter 2# Zooplanktonthe various free-floating animals.Copepods、Chaetognatha、Mysidacea、Protista、Sarcomastigophora、Foraminiferida、Radiolaria、Cnidaria，etc.# Holoplanktonthose organisms that spend their entire lives in the plankton.# Phytoplanktoncomprise the free-floating plants of the sea that are capable of photosynthesis.diatoms and dinoflagellates.# Primary productivitythe rate of formation of energy-rich organic compounds from inorganic materials# Measurement of Primary ProductivityLight-dark bottle methodNet photosynthesis=O2 in light bottle-O2 in initial bottleGross photosynthesisO2 in light bottle-O2 in dark bottle14C method（Rs-Rb)WP = —————R×NP: primary production; Rs: 14C in light bottle;Rb: 14C in dark bottle; W: total CO2 in seawater;R: 14C added in; N: incubation time.Chlorophyll methodP=Chl a content ×QP: primary production;Q: assimilation index(同化指数)# Standing crop of phytoplankton in the oceans is a difficult factor to measure accurately because of:1. The patchy distribution of plankton organisms.2. The problems of sampling.3. The problems inherent in the methods.The usual method of measuring standing crop is to measure the chlorophyll a content of a given volume of sea water.# Factors Affecting Primary Productivity1.Physical and chemical factors:Light: Factors affecting primary production include absorption of light by the water, the wavelength of light, transparency of the water, reflection from the surface of the water, reflection from suspended particles, latitude, and season of the year.2. NutrientsN, P, SiO2, and other inorganic or organic nutrients.3. Turbulence and critical depth# Geographic Variations in ProductivityTropic seas:The productivity there is low but constant throughout the year. The reasons is listed below:(1) The upper waters are well lighted and maintains higher temperature than deeper waters. So there is a thermal tratification throughout the year.(2) Mixing can not occur.(3)There are few phytoplankton in the water.Temperate seasThe light, temperature, mixing and productivity change seasonally in temperate seas. There is a major peak(高峰) in spring, a lesser peak in the fall(秋季), and low productivity in winter and summer. We may explain this as follows:(1) The low winter productivity is because of low light levels and because the mixing carry plant cells below the critical depth.(2) The spring bloom is because of the increased light and temperature, no mixing and because nutrients have been replenished(再充满) during the winter mixing.(3) The nutrient replenishment ceases because of thermal stratified in summer.(4) The thermal stratified begins to break up and nutrients are returned in the fall, A small bloom will occur.Polar seasIn the polar sea, Productivity is restricted to a single short period in summer, usually July or August.Light is the only reason.============================================================= ==========Chapter 3# Composition of the oceanic nektonfish、marine mammals、reptiles、seabirds# Adaptations of oceanic nektonBuoyancy、Locomotion 、Surface of resistance and body shape、Defense and camouflage、Sense organs、Echolocation、Reproduction and life cycle、Migration、Special adaptations of marine mammals# Surface of resistance and body shapea. The resistance include frictional resistance, form resistance, and induced drag.b. The best streamlined body gives the lowest resistance.c. Other adaptations of body shape: no protuberances, no hair or reduced in length, flattened mammary glands.# Special adaptations of marine mammalsa. To maintain temperature: a large body, a thick insulating layer of blubber, and using the circulatory system.b. To maintain diving: store more oxygen, a large blood volume, bradycardia, no blood supply to organs, and tolerance of anaerobic conditions, etc.c. To maintain osmotic regulations: salt-secreting glands, a large kidney, etc.============================================================= ==========Chapter 4# Zonationa. Pelagic zones: epipelagic or photic; mesopelagic or disphotic; bathypelagic, abyssalpelagic, hadalpelagic(aphotic)b. Benthic zones: continental shelf or sublittoral; bathyal; abyssal; hadal.# Adaptations of deep-sea organismsa. adaptation to the darkb. adaptation to the rare foodc. adaptation to the rare populationd. adaptation to the high pressuree. adaptation to the soft ooze(软泥)============================================================= ==========Chapter 5# The Sublittoralcovers that area of the oceans that lies between the area of lowest low water on the shore to the edge of the continental shelf at a depth of about 200m.# Environmental Conditions in the sublittoral1. The neritic waters show more variability in environmental conditions: wave action, salinity, temperature, light, etc.2. Productivity is generally higher because of nutrient abundance.3. The four major habitat types: open unvegetated sedimentary environments, hard substrates dominated by low-encrusting plants and animals, kelp beds and forests, and seagrass beds.# seagrass have a very high productivity rate, because of:a. Seagrass beds are densely covered with plant.b. They are capable of extensive nutrient cycling and regeneration.c. They cover such extensive areas in continental shelf waters.============================================================= ==========Chapter 6# Adaptations of Intertidal Organimsa.Resistance to water loss: The simplest method is moving from the exposed surface into very moist cracks(裂缝), and burrows(洞穴);Some large algae are adapted to withstand severe(严厉的) loss of water from their tissues;Many species of intertidal animals have mechanisms for prevention of water lossb.Maintenance of heat balance: Reducing the heat gain from the environment;Increasing the heat loss from the bodyc.Feeding: Most diurnalrocky intertidal animals are active only during the time the tide is in and they are covered with water;Nocturnal animals may also be active at low tides at night.d.Salinity stresse.Reproduction============================================================= ==========Chapter 7# Composition of coal reefsFish，sea urchin, branching coral, brain coral, sea fan, soft corals, sea whip, stinging coral，coneshell, cowry, sea star, polychaete, crinoid, sponges, holothurian, etc.# Associated organismsMangrove fauna，mollusks, certain crustaceans, and some peculiar fishes.============================================================= ==========Chapter 8# Net reproductive rate(R0)the average number or offspring produced by an individual in a population.R0 =∑lxmxlx is the proportion surviving to day x;mx is the average number of seeds per individual during time interval.# The generation time(T)the average time from egg to egg, seed to seed, and so forth.∑ xlxmxT =----------R0In this equation x is age in years.# The per capital rate of increase(r）r=b-d;b: birth rate; d: death rate============================================================= ==========Chapter 9# Logistic population growthAs resources are depleted, population growth rate slows and eventually stops# Logistic equationdN/dt=rmN((K-N)/k)rm: intrinsic rate of increase; N/K: environmental resistance============================================================= ==========Chapter 10# Cleaning behaviorVarious species of fishes and shrimps actively attract large fishes to themselves for the purpose of cleaning them of various ectoparasites# The main types of symbiotic relationships among marine organisms Commensalism, Inquilinism, Mutualism, Parasitism, Amensalism, Protocoperation# Modifications due to the association of animal-animal symbiosis relationshipa. The animal-animal relationships can result in anatomical, physiological, and behavioral modifications to one or both of the partners.b. The fewest modification occur among the epizoites.c. recognition (most like a chemical, unique to the host, released into the water) and sensory receptors.d. The tube-dwelling symbionts are often smaller or thinner and flatter than their free-living relatives.e. The crabs carry the anemones with their chelae.f. Acclimatization: The fish coats itself with anemone mucus, thus tricking the anemone to discern the fish as itself.g. The anemone fish swim toward the predator and have vivid color to attract the predator.h. Cleaning fishes have narrow snouts and forcepslike teeth.============================================================= ==========Chapter 11# the human impact on the sea1.Fisheries: In recent years, there have a lot of examples of the decline of fish stocks of all types in all areas of the world. some of these declines are clearly due to instances of overexploitation.2.Mariculture: Mariculture encompasses marine organisms raised not only for human food, but also for other products, such as pearls, and terrestrial animal food. But there are also someProblems and restrictions to mariculture developmen：such as Space, disease, nonpelagic, pollution, etc.3.Pollution：Oil，Sewage and Garbage，Chemicals，Radioactive wastes and Miscellaneous pollution problems# Discuss the red tide phenomenon in the oceanRed tides are a marine phenomenon in which water is stained a red, brown, or yellowish color because of the temporary abundance of a particular species of pigmented dinoflagellates (these events are known as "blooms"). Also called phytoplankton, or planktonic algae.Under appropriate environmental conditions, various species can grow very rapidly, causing red tides. Red tides occur in all marine regions with a temperate or warmer climate.The environmental conditions that cause red tides to develop are not yet understood. However, they are likely related to some combination of nutrient availability, nutrient ratios, and water temperature.it is suspected that human activities that affect nutrient concentrations in seawater may be having an important influence on the increasingly more frequent occurrences of red tides in some areas. complex global changes in climate also may be affecting red tides. Water used as ballast in ocean-going ships may be introducing dinoflagellates to new waters.Sometimes the dinoflagellates involved with red tides synthesize toxic chemicals. The algal poisons can accumulate in marine organisms they can poison the human beings who eat them. Marine toxins can also affect local ecosystems by poisoning animals.Red tides can cause ecological damage when the algal bloom collapses. Undersome conditions, so much oxygen is consumed to support the decomposition of dead algal biomass that anoxic conditions develop. This can cause severe stress or mortality in a wide range of organisms that are intolerant of low-oxygen conditions. Some red tide algae can also clog or irritate the gills of fish and can cause stress or mortality by this physical effect.。