Evolution of Biodiversity

Diversity of Species Biodiversity a. ecosystem diversity b. species diversity c. genetic diversity

Species Richness a. number of species in a given area b. used to give approx. sense of biodiveristy in a given area Species Evenness a. relative proportions of individuals within the different species b. low and high evenness

Phylogeny a. evolutionary history of organisms b. shows relationships among species c. phylogenetic tree

Charles Darwin’s Theory of Evolution Galapagos Islands a. Darwin’s finches

Origin of Species by Natural Selection – by Charles Darwin Evolution – concept that species have changed over time a. microevolution vs. macroevolution

Natural Selection “organisms best suited to their environment reproduce more successfully than other organisms” * Adaptation * *selection conditions change as the demands of the environment change *if change is too extreme and organism can’t change, they become extinct or die

Genetic Drift a. change in genetic composition of a population over time as a result of random event b. biggest impact on SMALL populations

Bottleneck Effect a. population bottleneck b. reduction in genetic diversity of a population caused by a reduction in its size c. low genetic variation = problems

Speciation “two species arise from one” Geographic isolation and reproductive isolation

Pace of Evolution Rate of environmental change Genetic variation Artificial selection Genetically modified organisms through genetic engineering

Ecological Niches and Species Distributions Niche - “way of life” a. range of tolerance b. fundamental v. realized niche c. niche generalists v. niche specialists

Extinction 3 reasons a. geographic location b. space c. adaptation Fossil record Mass extinctions a. 5 global b. possible 6 th – human causes (dramatic and sudden)