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

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Presentation on theme: "Evolution of Biodiversity. Diversity of Species Biodiversity a. ecosystem diversity b. species diversity c. genetic diversity."— Presentation transcript:

1 Evolution of Biodiversity

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

3 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

4 Phylogeny a. evolutionary history of organisms b. shows relationships among species c. phylogenetic tree http://www.macalester.edu/~montgomery/GrayWolfExtra.html

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

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

7 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

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

9 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

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

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

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

13 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)


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