env s study guide 2

Env s study guide 2 - Week 4 Ecosystems and biogeography Fundamental characteristics of an Ecosystem1 Structureliving and non-living 2

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Week 4 -- Ecosystems and biogeography Fundamental characteristics of an Ecosystem- 1. Structure—living and non-living 2. Process—cycling of biomass and nutrients, energy flows 3. Function—observed rates of energy flow and cycling of chemicals 4. Change—succession Trophic levels - in an ecological community, all the organisms that are the same number of food- chain steps from the primary source of energy. For example, in grassland the green grasses are on the first trophic level, grasshoppers are on the second, birds that feed on grasshoppers are on the third, and so forth. Net primary production - the production that remains after utilization. In a population, net production is sometimes measured as the net change in the numbers of individuals. It is also measured as the net change in biomass or in stored energy. In terms of energy, it is equal to the gross production minus the energy used in respiration. Nutrient cycling - much like biogeochemical cycle; nutrients go from one cycle to another within biome Ecosystem services- 1. Food and fiber production (agriculture, rangeland, fisheries) 2. Soil stabilization and flood control 3. Water quality treatment and sediment trapping (wetlands) 4. Climate regulation and biogeochemical cycling 5. Biodiversity (medicines, industrial products, foods) 6. Aesthetics and recreation Keystone species - a species, such as the sea otter, that has a large effect on its community or ecosystem so that its removal or addition to the community leads to major changes in the abundances of many or all other species (bison, sea otter) Biome - is a kind of ecosystem. Rainforest is an example of a biome. Rain forests occur in many parts of the world but they are not all connected to each other; it is the largest classification of vegetative structures.
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The distribution of species - Week 5 –- Biodiversity Biodiversity - refers to the variety of life forms, commonly expressed as the number of species in an area, or the number of genetic types in an area. Biological evolution - coined by Charles Darwin, refers to the change in inherited characteristics of a population from generation to generation. It can result in new species—populations that can no longer reproduce with members of the original species. Can result in new species or adaption of existing species, there are four processes, once a species is extinct it is gone forever, makes sense of life that we observe in the field and laboratory (only theory that does) Mutation Migration (geographic isolation) - when a species gets separated due to migration or other biological reasons, they acquire new specialized roles or genetic changes. Darwin, in studying the finches of the Galapagos Islands, figured out that the finches adapted to different niches (societal roles) and he labeled this theory adaptive radiation, and they can no longer reproduce with the original species. Genetic drift (earthquake, storm, flood…)-
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This note was uploaded on 08/26/2011 for the course ENVIRONMEN 2 taught by Professor Staff during the Spring '11 term at UCSB.

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Env s study guide 2 - Week 4 Ecosystems and biogeography Fundamental characteristics of an Ecosystem1 Structureliving and non-living 2

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