1. Evolution and Behavior
Chapter 4

2. Gull Nesting Behavior
Herring Gulls

3. Gull Nesting Behavior
Kittiwakes

4. Natural Selection
3 requirements

5. 1. Variation

6. 2. Heritable

7. 3. Differential Survival/Reproduction

8. Genetic Variation
Common
Mutation
Recombination

9. Response to Selection Selection acts on populations
Different outcomes of selection

10. Other mechanisms Why hasn’t selection weeded out variation? Gene flow
funnel-web spiders
insectivorous
dry vs. riparian areas
different behaviors
grassland—more aggressive to prey and competitors, less worry about predators

11. Tested for genetic differences How?
lab and field experiments
BUT, found a riparian population that didn’t behave as it should. Using a drift fence, researchers demonstrated gene flow; the isolated population they changed to “correct” behavior

12. Other Mechanisms Genetic Drift
populations in isolation

13. Other Mechanisms Genetic Drift
populations in isolation

14. Other Mechanisms Correlated Traits
Pleiotropy
Linkage
Beak size in Darwin’s Finches—food and song

15. Other Mechanisms Environmental Factors
Time lags
Some due to humans
Evolutionary Arms race (bats/moths)

16. Other Mechanisms Frequency-dependent Selection
Rare alleles have a selective advantage
Predation – predators may select the most common morph

17. Other Mechanisms Frequency-dependent Selection
Reproduction – rare male effect
Can change allele frequencies

18. Other Mechanisms Negative-Assortative Mating
Opposites attract—mates choose different phenotypes
Tan—better dads, but white females outcompete for mating
Reason?

19. Other Mechanisms Evolutionary Stable Strategies
Your strategy depends on others
when adopted by all members of a population, unbeatable

20. Other Mechanisms Evolutionary Stable Strategies
Pure
Mixed
Digger Wasps

21. ESS Digger = 0.96 egg/100 hrs Enter = 0.84 egg/100 hrs
Digger wasps--when to dig, when to invade
Has to have equal fitness
Digger = 0.96 egg/100 hrs
Enter = 0.84 egg/100 hrs

22. Testing hypotheses Adaptive storytelling Better experimental design
Reproductive success

23. Testing hypotheses
Experimental Approach

24. Testing hypotheses Comparative Approach - evolutionary relationships
Test alternatives (correlation ≠ causation

25. Measuring selection
Easy in the lab; field is a different story

26. Measuring selection
Easy in the lab; field is a different story