GEOG 1010 Lecture Notes - Lecture 21: Species Richness, Local Extinction
Document Summary
Population: a group of individual organisms of the same species occupying a given area at the same time. Community: groups of interacting populations of different species in the same place at the same time. Ecosystem: self-sustaining association of living plants, animals & non-physical environment. Biomes: dominant vegetation formation associated with specific climatic conditions. Variability among living organisms from all sources & the ecological processes they are a part of, this includes diversity within species, between species , within communities, ecosystems & landscapes. 1. 75 million species known to western science, estimates of 4-30 million species. Species diversity ( combination of species richness & evenness) Species richness: number of species per unit of area (i. e. a count) Species evenness: distribution of individuals among species (i. e. a measure of equitability) Species is lost from one or more geographic areas, but exists elsewhere. Once per 25-75 million years over 450 million years.
