1. Evolution

2. The change of a population’s genetic makeup through successive generations Populations, not individuals evolve by becoming genetically different All species descended from earlier, ancestral species Evolution is Fact – Natural Selection as a mechanism is a Theory

3. Evolution by Natural Selection Evolution had been thought of for centuries but mechanism was unknown Charles Darwin (1809-1882) wrote “The Origin of Species by Means of Natural Selection” in 1859 and put forth a mechanism Studied Galapagos ecosystem as a ship’s naturalist

4. 5 Premises 1. Stability in reproduction 2. Overproduction 3. Chance variation that can be inherited Acquired traits cannot be passed on Must be genetic variation 4. Natural Selection by environment Differential reproductive success 5. Accumulated changes leads to differentiation

5. Micro vs. Macro evolution Microevolution – Small genetic changes that occur in a population Macroevolution – Long-term large-scale evolutionary changes among groups of species in which new species are formed from ancestral species and other species are lost through extinction

6. Microevolution Must be genetic variability in the population –Gene pool –Alleles 4 Processes: –Mutation - DNA –Natural Selection – genetic bias for selection –Gene Flow - movement –Genetic Drift – chance –(artificial selection)

8. Macroevolution Speciation – Creation of a new species Process: –Geographic Isolation (Allopatric) –Reproductive Isolation (Sympatric) Premating Postmating

9. Natural Selection Competition Differential survival and reproduction Survival of the fittest?

10. Natural Selection Stabilizing Selection: Affects the extremes of the population Directional Selection: Affects the extremes of one end of the population Disruptive Selection: Acts against the “average” of the population Frequency-Dependent Selection: Decreases the frequency of more common phenotypes Sexual Selection

11. Coevolution When populations of two different species interact over a long period of time, changes in the gene pool of one species leads to changes in the gene pool of the other species Predator and prey; flowers and polinators Mullerian mimicry = toxic look-alikes Batesian mimicry = non-toxic look-alikes –Based on first impressions

12. Convergent vs. Divergent Evolution Convergent Different ancestry Same environment Whales and sharks Divergent Same ancestry Different environment Brown vs. polar bears Penguins vs. other birds

13. Gradualism vs. Punctuated Equilibrium Gradualism: Evolution occurs as a slow stepwise development of a species over long periods of time (millions of years) Punctuated Equilibrium: Some species arose suddenly in short periods of time (thousands of years)

14. Extinction Permanent loss of genetic diversity that affects the evolution of macro evolutionary images Background extinction Mass extinction

15. How does evolution affect biodiversity? Speciation minus extinction equals biodiversity Extinction is a natural process

16. Misconceptions about Evolution Survival of the fittest is different from survival of the strongest Humans did not evolve from apes, they both evolved from a common ancestor Species are not becoming more “perfect”

17. Theory vs. Fact Scientific theories = integrated explanation of many hypotheses –There is always uncertainty –Not the same as common language –Can only disprove Facts are pieces of information that have not been refuted

18. Factual Evidence for Evolution 1. Small-scale changes observed or produced 2. Large-scale changes in the fossil record Evolution is not a ladder but a tree Temporal sequences have been found 3. Vestigial signs present today