ENVIRSCI 214 Lecture Notes - Lecture 23: Biogeography, Beta Diversity, Alpha Diversity
14 Apr 2017
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Document Summary
Biogeography- large scale patterns of distribution and diversity of organisms. Patterns of species composition and diversity across geographic regions. Search for patterns of plant and animal life that can be put on a map. Species diversity combines two aspects: species richness: number of species in a community (does not distinguish rare species from common species, species evenness: relative abundance of the different species (rare vs. common) Species diversity indices: shannon index gives snapshot of diversity- values alow comparison across time or across places. Calculating species diversity h: example- 2 communities with five species each (species richness is equal) In community a, one species constitutes 84% of the individuals, the other species are 4% each. In community b, the abundance is equally divided, each species is 20%. Greater species evenness means a higher species diversity. This results in plant galls, which are like tumors on the plant that envelop the growing insect and supply it with nutrients.
