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Unformatted text preview: .5 .5 1 .5 .5 .25 .25 .25 .25 .25 .25 Biodiversity What is Biodiversity? I t is the variety of ecosystems, species, populations within species, and genetic diversity among and within these populations. Why is it important? I t is important for the resources we use (bioresources), for the ecosystem services it provides, for the pleasure we derive from living organisms (aesthetic) and for ethical reasons. Stochastic Factors- Demographic stochasticity- unfavorable death rates or population • Genetic stochasticity- chance occurrence of unfavorable genetic circumstances ♦ I nbreeding depression- reduced fitness • Environmental stochasticity- unusual levels of predation, parasitism, disease, etc. ♦ Natural catastrophes- floods, fires, droughts, heat/cold Levels of Biodiversity: Genetic diversity, species diversity, ecosystem diversity Genetic Diversity- raw materials for selection and adaptation. Higher vs. lower • Higher- greater chance some individual can adapt to changing environment. • Lower- uniformity or homozygosity • High environment variability associated with higher genetic diversity Species diversity (most studies) • Species r ichness- number of species • Evenness- what extent are individuals distributed among species • Differences- relatedness Ecosystem Diversity- species distributions of communities and patterns, role and function of key species, interactions between species • (alpha diversity)- α within ecosystems • (beta diversity)- β between ecosystems • (gamma diversity)- γ across large geographical scale Evolution (biological or organic)...
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This note was uploaded on 11/07/2010 for the course NRM 2307 taught by Professor Kerrygriffis-kyle during the Spring '10 term at Texas Tech.
- Spring '10