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1、生态学（英文版）Ecology (生態學IntroductionEcology -Concept of the ecosystem - The biosphere and biomes Bioshpere 生物圈o The part of the Earth and its atmosphere inhabited by life is called biosphereo Thus, the oceans, land surface and lower parts of the atmosphere all form parts of the biosphere. Biome 生物群落o Th
2、e biosphere can be divided into biomes which are linked by a common type of vegetation.o Forests, deserts and grasslands are the examples of biomes. Each biome consists of many ecosystems in which communities have adapted to differences in climate, soil, and other environmental factors throughout th
3、e biome.A. The Ecosystem 生態系統An ecosystem is defined as a complex formed by the living community of different species interacting with one another and with their non-living environment of matter and energy to result in a stable and self-sustainable system.Components of an ecosystem : living communit
4、y and non-living component A population 種群 consists of all members of the same species occupying a given area at the same time. A community 群落 consists of Populations of all the different species interacting with one another A habitat 生境 is a small specific place where an organism lives.- types of h
5、abitats :terrestrial habitat forest, aquatic habitat fresh water : pond, lake, reservoir, marine : sandy shore, muddy shore, A habitat can divide into numerous microhabitats 小生境,eachwith The niche 生態位 of a species describes the role of specific species in its community. Niches are sometimes distingu
6、ished from habitats by saying that the habitat of an organism is its address, while its niche is its role in the community.e.g. on a tree : caterpillars (feed on leaves), beetles (burrow into trunk) they live on same place but functionally they occupy different niches. The biotic (living) factors 生物
7、的 are comprised by all living organisms within the ecosystem. The abiotic (non-living) 非生物的 factors are mainly divided into soil, water and climate.o Water is essential for all living organisms in the soil and enters living cells by osmosis.o Soils vary in their content of clay, silt, sand and grave
8、l. The composition of soil determines the soil texture, porosity, water-retaining capacity and oxygen content. Soil contains a mixture of organic and inorganic nutrients (humus and minerals).o Climate includes environmental variables such as light, temperature, moisture, salinity and wind. These fac
9、tors are important in determining the types of living organisms in the ecosystem.B. Energy flow and nutrient cycling in the ecosystem【)Transfer of energy (many approaches, according to functions in ecosystem) Food chainA linear sequence of organisms showing a pathway of food consumption from produce
10、rs through a series of consumers. In this series, an organism feeds on the one before it and forms the food of the organism after it.Food chains are short (4-5 levels) because only 10 - 20 % of energy is transferred to the next stage.Each stage in food chain = Trophic levels The number of steps by w
11、hich the organisms obtain their energy from plants in afood chain. -the producers always at the first trophic level.Producersconsumersconsumersconsumersa) Producers : autotrophs 自養 -photosynthetic e.g. green plant, photosynthetic bacteria, chemosynthetic bacteria e.g. nitrifying bacteria, base of fo
12、od chain and food web.N.B. : Phytoplanktons, which are microorganisms, are important producers floating on the upper layers of lakes or ocean. They are unicellular organisms which also contain chloroplasts to carry out photosynthesis just like the terrestrial plants .b) Primary consumers : herbivore
13、s which feed on plants e.g. pond snails, insect larvae.c) Secondary consumers : carnivores which feed on primary consumers e.g. small fish.d) Tertiary consumers : larger carnivores which feed on secondary consumers e.g. large fishe) Decomposers : mainly 分解者decompose dead bodies of plants and animals
14、 into simpler compounds which can then be absorbed by green plants again,important in recycling of nutrients and clearing up dead bodies and excretory remains.f) Detritivores : consume the losses from the food chain, or dead organic matter detached食腐質動物from dead bodies or excreta (detritus), movemen
15、t of energy and matter in a continuous manner, therefore hard to define trophic level, mainly bacteria, fungi, protozoans, insects, mites and some small vertebrates,detritus detritivores carnivores and herbivoresImportances: detritivores break down complex compounds to simpler molecules, therefore s
16、peeding up decomposition of dead bodies and excretory remains by breaking up detritus into small pieces thus increasing the surface area available for microbial action, adding proteins and microorganisms onto the soil by their faecesg) other definition system :Producer herbivorescarnivorestop carnivores(prey)(prey/pre
