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

2. So, what is evolution? Change in a species over time
Why do we get a flu shot every year?
Why are some bacteria resistant to antibiotics?
Why are humans taller than they used to be?
Why are bedbugs suddenly so common?

3. 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

4. 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

5. 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

6. Stabilizing Natural Selection

7. Directional Natural Selection

8. Disruptive Natural Selection

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

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

14. Speciation Rates
Gradualism vs Punctuated Equilibrium

15. 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

16. Hawaiian Honeycreepers

17. Convergent evolution
When distantly related species evolve similar traits because of similar environments

20. Adaptations
Structural
Mimicry
Camouflage
Physiological

21. Other evidence for evolution
Fossils
Homologous structures
Analogous structures

22. Vestigial structures
Embryology
Biochemistry
DNA
ATP