群落之间的相互作用∶

1. Interspecific competition 种间斗争

（Intraspecific 种内）

Two or more species compete for the same limited resources. 

Result: extinction, resources partitioning, and character displacement

2. Predation 捕食

One organism (predator) feeds on another organism (prey)

捕食方法∶ pursuit and ambush; mimicry; camouflage; chemical warfare

保护方法∶ Aposematic coloration 警戒色; Batesian mimicry 警戒拟态; Mullerian mimicry

3. Symbiotic relationship 共生

Mutualism 互利共生 → both species benefit

Commensalism 偏利共生→one species benefits and the other is neither helped nor hurt

Parasitism 寄生→ one species is harmed and the other benefits

重要的生物

Keystone species 基石物种 the biotic balance is maintained by a single species

Indicator species 指示物种 species that are used as a standard to evaluate the health of an ecosystem 

Indigenous species 本地物种 species that originate and live or occur naturally in an area or environment

Biomes 生物群系

Ecotones 交错群落: the transitional area where two ecosystems meet

Ecozones/Ecoregions: smaller regions within ecosystems that share similar physical features

Edge effect: some organisms can only live in ecotones (交错群落), which can be destroyed by habitat fragmentation

Law of Tolerance: the degree to which living organisms are capable of tolerating changes in the environment 

Law of the Minimum 最小因子法则: living organisms will continue to live, consuming available materials until the supply of these materials is exhausted.

Forest 森林∶

特点∶ high productivity and biodiversity

Tropical rain forest∶ 低纬度地区（巴西、中美洲、印尼、中非），土壤贫瘠←leaching

Temperate rain forest∶ 中纬度地区（美国东部，欧洲大部分），土壤肥沃

Taigas（boreal forest）北方针叶林∶北极苔原以南（北美、亚洲、欧洲的北部），植物多样性低，土壤贫瘠且显酸性

Grassland 草原∶

特点∶regulated by seasonal drought， occasional fires，and the grazing of herbivores

Tropical grassland∶东非、南美洲和澳大利亚的部分地区，干湿季交替，植物根系发达

Temperate grassland∶美国和加拿大的中西部和西部、南非和俄罗斯的部分地区，生产力高，大风和蒸发较强使得夏秋季容易着火

Cold grassland∶北极苔原以南（北美、亚洲、欧洲的北部），动物的适应能力强

Desert 沙漠∶

特点∶ intense heat and evaporation

Tropical desert∶大多数的北非、中东的部分地区，植被稀少

Temperate desert∶美国西南部，存在一些抗干旱的植被

Cold desert∶ 美国大盆地、中国北部的戈壁、蒙古南部，植被稀少

Chaparral（temperate shrubland）灌木丛∶

南加州的沿海地区、地中海的部分地区、智利中部

Energy Flow 生态系统中的能量流动

Producer （autotroph）生产者∶

At the first trophic level 第一营养级

Photosynthesis 光合作用∶Solar energy+6H2O+6CO2→ C6H12O6+6O2

Chemosynthesis 化能合成作用∶Heat +3H2S+6H2O+6CO2→C6H12O6+3H2SO4

Consumer （heterotroph）消费者∶

Aerobic respiration 有氧呼吸∶C6H12O6+6O2→6H2O+6CO2+energy 

Primary consumer: herbivores

Secondary & tertiary consumer: carnivores and omnivores （杂食公务）

Detritivores 食腐质者∶scavengers （larger organisms）

Decomposers 分解者∶ bacteria and fungi; support the growth and development of primary producers

Ethanol fermentation 酒精发酵∶C6H12O6→2C2H5OH+2CO2

食物链和食物网

Food chain 食物链

Food web 食物网：越复杂，群落的稳定性越强

Gross primary productivity: the rate at which primary producers converts solar energy into chemical energy through photosynthesis

Net primary productivity= gross primary productivity -aerobic respiration(by plants)

NPP=GPP-R

Energy pyramid 能量金字塔∶

营养级之间的能量传递效率很低，大约为10%

Bioaccumulation: the accumulation of a substance in the tissues of a living organism

Biomagnification: the increasing concentration of toxin molecules at successively higher trophic levels in a food chain

二者提及的物质大都为毒素或重金属等有害物质。

DIVERSITY

自然选择的影响因素∶

Geologic events: tectonic activity and movement of continents; earthquakes and volcanos Climate events: periods of warming and cooling

Speciation 新物种的形成∶

Geographic isolation 地理隔离 →Reproduction isolation 生殖隔离

生物的进化

Divergent evolution: ancestral species → new species 

Convergent evolution: unrelated species → similar adaptations 

Parallel evolution: common ancestor → related species

Coevolution: reciprocal evolutionary set of adaptations of interacting species 

Adaptive radiation: each newly emerging form specializes to fill an ecological niche

Genetic drift 遗传漂移∶

The accumulation of changes in the frequency of alleles (versions of a gene) over time due to sampling errors—changes that occur as a result of random chance 由于随机交配导致的等位基因频率变化。

Extinction 灭绝∶

Biological extinction: the true extermination of a species

Ecological extinction: organisms are so few that this species can no longer perform their ecological function 

Commercial or economic extinction: organisms are so few that the effort needed to locate and harvest them is not worth the expense

MATTER CYCLE

碳循环

Process:

Photosynthesis and Respiration Exchange, Sedimentation, and Burial Extraction and Combustion

Importance:

1. Critical for: nucleic acids, carbohydrates, proteins, lipids 

2. Largest reservoir: oceanic sediments

3. Atmosphere: acts as a natural thermostat for earth's surface temperature

Human Impacts: 

Combustion of fossil fuels; 

Tree harvesting/Clear-cutting

氮循环

Nitrogen cycle is the limiting factor for primary producers.

Process:

Nitrogen fixation: N2→>NH4+&NH3 

Nitrification: NH4+&NH3→NO2- → NO3-

Assimilation: producers incorporate elements into their tissues

Mineralization: organic matters → inorganic compounds (by decomposers)

Ammonification: organic nitrogen →NH4+ & NH3(by decomposers)

Denitrification:NO3-→N2O→N2

Importance:

1. Critical for: proteins, nucleic acids 

2. Largest reservoir: the atmosphere

Human Impacts:

Excess nitrates, causing leaching; 

Burning of fossil fuels; 

Using inorganic fertilizers

磷循环

Process:

Assimilation and Mineralization

Sedimentation, Geologic Uplift, and Weathering

Importance:

1. Critical for: DNA, ATP, the bonds and teeth of vertebrates 

2. Largest reservoir: oceanic sediments and terrestrial rock layers

Human Impacts:

Eutrophication 富营养化， causing algal boom and then hypoxic water

硫循环

Importance:

1. Critical for: proteins, vitamins 

2. Largest reservoir: oceanic sediments

Human Impacts:

Acid deposition(SO2 → H2SO4)

水循环

Process: Precipitation Transpiration Evaporation

Importance:

1. Critical for: life

2. Largest reservoir: surface water

Human Impacts:

Unsustainable withdrawal of water 

Removal of wetlands and deforestation 

Urbanization

影响气候的因素

Albedo 反照率∶冰雪有较高的反照率，海水的反照率较低

Greenhouse effect 

Carbon Cycle

Landmass distribution 大陆分布

Precession 旋进∶地球绕地轴转动影响气候

Volcanos and plate tectonics

生态演替

Primary succession 原生演替∶之前没有土壤存在，后来演变为有生物的地方

Secondary succession 次生演替∶之前有土壤存在，被毁掉后还有些残留，后来演变

Pioneer species: species that in the first states or either type of succession 

Climax community: the final stage of succession