1. The Theory of Evolution
Chapter 15
The Theory of Evolution

2. Theory of Evolution
Idea supported by scientific evidence (but no concrete experiments) over a long period of time
Change in a species due to mutation of the DNA code that occurs over a long time

3. Evolution Evidence: 1. Adaptations 2. Fossils 3. Comparative anatomy
4. Comparative embryology
5. Comparative Biochemistry
6. Plate Tectonics

4. Evolution of Brains:

5. Charles Darwin Developed theory of evolution
Based it on natural selection
Visited the Galapagos Islands

6. Trip of Darwin and HMS Beagle

7. Natural Selection
Something in nature chooses who is most suited for the environment
Certain individuals have better traits for an environment than others – inherited or random mutation
They will survive to reproduce, passing on that desired adaptation
Those who do not have the desired trait, most likely, do not reproduce and will die

8. So, who evolves? Populations, not individuals!!!!!
Evolution works on phenotypes, not genotypes!!!!!
Individuals with the desired trait help change the overall appearance of the population
Gene pools will change due to mutations, gene recombinations, and reproduction rates
The most evolution will occur in large populations that undergo sexual reproduction

9. Adaptations: features suited to a particular environment that allow organisms to survive
Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.

10. Masai people, who live in the arid lands of eastern Africa, have tall, lean bodies that disperse heat well.

11. Stabilizing Natural Selection genetic diversity decreases and the population mean stabilizes on a particular trait value

12. Directional Natural Selection an extreme phenotype is favored over other phenotypes

13. Disruptive Natural Selection Extreme values for a trait are favored over intermediate values. Often results in the population divided into two distinct groups.

15. Charles Darwin Developed theory of evolution
Based it on natural selection
Visited the Galapagos Islands

16. Trip of Darwin and HMS Beagle

17. Artificial Selection
Humans interfere with nature picking the best suited.
Humans select the most desired traits and allow only those individuals to reproduce
Farmers, animal breeders

18. Speciation The evolution of species
Occurs when members of similar populations no longer interbreed to produce fertile offspring
Geographic isolation
Behavioral isolation

20. Finches of the Galapagos

21. Speciation Rates
Gradualism vs Punctuated Equilibrium

22. Patterns of Evolution Adaptive radiation (divergent evolution)
When an ancestral species gives rise to many new species
Each new species is adapted to a specific niche
Darwin’s finches
Hawaiian honeycreepers

23. Hawaiian Honeycreepers

24. Convergent evolution…slide 1
When distantly related species evolve similar traits because of similar environments

25. Convergent evolution---slide 2

26. Convergent evolution…slide 3

27. Adaptations- Evidence of Evolution…pg 397
Structural- next slide
Mimicry-below, pg 398
Camouflage- leaf frog-->
Physiological-Plant/animal cells

28. Other Evidence for Evolution
Fossils: Ch 14
Homologous structures
Common evolutionary ancestor
Similar in arrangement/function or both
Analogous structures
Similar in function, but not a similar ancestor.

29. More Evolutionary Evidence
Vestigial structures
Whale pelvic bone…pg 402
Embryology--->
Lizard, Tortoise, Pig, Human
Biochemistry
DNA
ATP