Study Notes - full set midterm 3

Study Notes - full set midterm 3 - BISC MIDTERM #3 10/30/07...

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BISC MIDTERM #3 10/30/07 Community and Succession - takes about 300 yrs for tropical forest to re-establish itself - dominance: by mass ‘biomass’ , which you can convert in to calories Biodiversity 1) species richness: number of that species per unit area/ volume 2) species diversity: identify and count all of the species. So you have no. of diff species and total number of all of them. You get a value between 0-5 . called the H prime” index. 3) Species ‘evenness’: how many species in an area. Opposite = dominance few species in an area, but big population. Number of species in different geographical locations (breeding of species by latitude). Evolutionary Time : how fast species evolve. Climatic Stability and predictability Spatial Heterogeneity Productivity : e.g more plants produced = more species in each trophic level. (deserts are different, because the productivity of plants etc. aren’t that much, but there are a big number of species.) Competition and Predation : - low intensity of predation = few dominant species there - moderate intensity = large number of species - high intensity = few survivable species. 500 rule: at least have this in a species to avoid ‘inbreeding’. 50: at least this much to have maintainable population. Succession: Replacement of species over time. Each stage of succession = serial stages. 2 concepts of succession - Clements Concept : plant succession development Primary succession: - Plants (mosses) grow on rocks, expands = breaks down into soil over thousands of years. - There are animals living in the mosses (microscopic), which contributes to the ecosystem. Then there will be trees later etc. and soil gets thicker and thicker. Secondary succession: -
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Will edventually reacha climax of community. “climax community” is where it stays for years to come. Gleson says: - succession is a RANDOM process. - Short lived species replaced by long lived species, therefore over time trees in a community are longest living ones. - Competition and Predation determines the outcome of the community. How long does succession last for plant communities? - for weeds etc., just 1 or 2 years. Redwood trees and Douglas Furs - if burned down to the ground, it takes 1000 years to re-establish the community. Tropical Rainforest - takes 300 years to become succession again. Is succession directional? - No. can go everywhere, BUT ends up at the same end point anyway. Stability of Communities: 2 aspects. 1) Resistance: shafforeal burns easily; redwoods are much much harder. 2) Resilience: ability to bounce back. Different kinds of climax communities: - Mono – climax : cold areas. Process of bedrock broken down etc = very slow, since its so cold there. -
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This note was uploaded on 06/21/2008 for the course BISC 102Lxg taught by Professor Kiefer,bakus during the Fall '06 term at USC.

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Study Notes - full set midterm 3 - BISC MIDTERM #3 10/30/07...

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