Evolution: The changes in the genes and the characteristics displayed by successive generations of a population of organisms over time. Natural selection is the mechanism that causes evolution to occur.(进化:生物在世代繁衍过程中 基因和特性的改变,其作用机理是自然选择) 4. Evolutionary Patterns(进化形式) Speciation: Production of new species from previously existing species Speciation is thought to occur as a result of a species dividing into two isolated subpopulations.(物种形成) Extinction: Loss of entire species Of estimated 500 million species of organisms believed to have ever existed on earth,98-99% have gone extinct.(物种灭绝) Coevolution: Two or more species can reciprocally influence the evolutionary direction of the other.(共同演化) 5. Kinds of Organism Interactions(生物相互作用) Predation: One animal kills and/or eats another. (f) ompetition: Two organisms compete to obtain the same limited resource, and both are harmed to some extent.(竞争) 6. Symbiotic Relationships(共生关系) Symbiosis: Close, physical relationship between two different species. At least one species derives benefit from the interaction (*f) Parasitism: One organism(parasite) living in or on another organism(host), from which it derives nourishment.(寄生) Commensalism: One organism benefits while the other is not affected. F* 生) Mutualism: Both species benefit-Obligatory in many cases as neither can exist without the other.(互利共生)
11 • Evolution: The changes in the genes and the characteristics displayed by successive generations of a population of organisms over time. Natural selection is the mechanism that causes evolution to occur.（进化：生物在世代繁衍过程中 基因和特性的改变，其作用机理是自然选择） 4. Evolutionary Patterns（进化形式） • Speciation: Production of new species from previously existing species. Speciation is thought to occur as a result of a species dividing into two isolated subpopulations.（物种形成） • Extinction: Loss of entire species. Of estimated 500 million species of organisms believed to have ever existed on earth, 98-99% have gone extinct.（物种灭绝） • Coevolution: Two or more species can reciprocally influence the evolutionary direction of the other.（共同演化） 5. Kinds of Organism Interactions（生物相互作用） • Predation: One animal kills and/or eats another.（捕食） • Competition: Two organisms compete to obtain the same limited resource, and both are harmed to some extent.（竞争） 6. Symbiotic Relationships（共生关系） • Symbiosis: Close, physical relationship between two different species. At least one species derives benefit from the interaction.（共栖） • Parasitism: One organism (parasite) living in or on another organism (host), from which it derives nourishment.（寄生） • Commensalism: One organism benefits while the other is not affected.（偏利共 生） • Mutualism: Both species benefit – Obligatory in many cases as neither can exist without the other.（互利共生）
7. Major Roles of Organisms in Ecosystems(生物在生态系统中的作用) Producers: Organisms able to use sources of energy to make complex organi olecules from simple inorganic molecules in the environment.(生产体) onsumers: Consume organic matter to provide themselves with energy and organic matter necessary for growth and survival.(消费体) Decomposers: Digest organic molecules in detritus into simpler organic compounds, and absorb soluble nutrients.(分解体) 8. Community and Ecosystem Interactions(群落与生态系统的相互作用) Keystone Species: Play critical role in maintenance of specific ecosystems. (X 键种) Energy Flow Through Ecosystems: Each step in the flow of energy through an ecosystem is known as a trophic level.(生态系统中的能量流,能量流的每一阶段 称之为营养级) Food Chain Passage of energy from one trophic level to the next due to one organism consuming another.(食物链) Nutrient Cycles in Ecosystems: Organisms are composed of molecules and atoms that are cycled between living and nonliving portions of an ecosystem. (E 态系统中的营养盐循环) 9. Succession(演替) Succession-A series of regular, predictable changes in the structure of a community over time.(演替:群落的规则性演变过程) Primary Succession -Begins with bare mineral surfaces or water and total lack of organIsms.(原生演替) Secondary Succession -Begins with disturbance of an existing ecosystem. (W 生演替)
12 7. Major Roles of Organisms in Ecosystems（生物在生态系统中的作用） • Producers: Organisms able to use sources of energy to make complex organic molecules from simple inorganic molecules in the environment.（生产体） • Consumers: Consume organic matter to provide themselves with energy and organic matter necessary for growth and survival.（消费体） • Decomposers: Digest organic molecules in detritus into simpler organic compounds, and absorb soluble nutrients.（分解体） 8. Community and Ecosystem Interactions（群落与生态系统的相互作用） • Keystone Species: Play critical role in maintenance of specific ecosystems.（关 键种） • Energy Flow Through Ecosystems: Each step in the flow of energy through an ecosystem is known as a trophic level.（生态系统中的能量流，能量流的每一阶段 称之为营养级） • Food Chain: Passage of energy from one trophic level to the next due to one organism consuming another.（食物链） • Nutrient Cycles in Ecosystems: Organisms are composed of molecules and atoms that are cycled between living and nonliving portions of an ecosystem.（生 态系统中的营养盐循环） 9. Succession（演替） • Succession - A series of regular, predictable changes in the structure of a community over time.（演替：群落的规则性演变过程） • Primary Succession - Begins with bare mineral surfaces or water and total lack of organisms.（原生演替） • Secondary Succession - Begins with disturbance of an existing ecosystem.（次 生演替）