生态学(英文版)

生态学(英文版)

Ecology (生態學)

Introduction

Ecology -- __________________________________________________________

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 biosphere

o Thus, the oceans, land surface and lower parts of the atmosphere all form parts of the biosphere.

•Biome 生物群落

o The 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 the 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 community 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 habitats :

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, each

with________________

_____________________________________________________________________

•The niche生態位of a species describes the role of specific species in its community.

Niches are sometimes distinguished 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 gravel. 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 factors are important in determining the types of living

organisms in the ecosystem.

B. Energy flow and nutrient cycling in the ecosystem

I) Transfer of energy (many approaches, according to functions in ecosystem)

Food chain

A linear sequence of organisms showing a pathway of food consumption from producers 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 which the organisms obtain their energy from plants in a food chain. --- the producers always at the first trophic level.