Evolution of Biodiversity

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
Natural Selection
“organisms best suited to their environment
reproduce more successfully than other
* 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
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
• “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
• Niche - “way of life”
a. range of tolerance
b. fundamental v. realized niche
c. niche generalists v. niche specialists
• 3 reasons
a. geographic location
b. space
c. adaptation
• Fossil record
• Mass extinctions
a. 5 global
b. possible 6th – human causes (dramatic and sudden)