Behavioral Evolution and Selection Strategies Lecture

Course Information

Bio 150, Bio 250, HumBio 160: No difference in course content, units, or requirements. Students can take whichever suits their schedule better.

Variety of Reasons: Students take the course for diverse reasons ranging from interest in animal behavior, substitution for Bio 43, childhood influences, to affiliations with TAs.
Interdisciplinary Interests: Examples include wanting to be a filmmaker and intersecting human biology with other fields.
Humorous and Relatable Responses: Comments like 'I often behave' and 'I date a biologist' highlight personal connections to the subject.
Popular Topics: Biology of religiosity and depression are recurring interests among students.

Analyzing Skulls: With the right tools, one can determine various characteristics like the likelihood of cheating, aggression levels, and parental styles from skulls of a species.
Examples from Nature: The giraffe’s heart and desert rodents’ kidneys illustrate the inevitable logic in biomechanics, also applicable to behavior.

Sociobiology and Evolutionary Psychology: Emerged in the 1970s-80s. Focus on understanding behavior through evolutionary context, building upon Darwin's principles.

Mechanism of Evolution: Natural selection, discovered along with Alfred Russell Wallace, is based on traits that are heritable, exhibit variability, and have adaptive advantages.
Adaptation and Reproduction: Evolution isn't just survival of the fittest but also reproduction of the fittest, focusing on gene propagation.

Group Selection Myth: Criticized by Wynne-Edwards. Animals do not behave for the good of the species but to maximize genetic copies in the next generation.

Individual Selection: Behaviors to reproduce and pass on genes. Examples include selfish genes and sexual selection.
- Sexual Selection: Traits favorable for mating may not necessarily be advantageous for survival, e.g., bright coloration in certain fish can attract mates but also predators.
- Nash Equilibrium: Optimal strategies in games like Tic-Tac-Toe can be applied to behaviors.
Kin Selection (Inclusive Fitness): Helping relatives can propagate shared genes. Famous Haldane quote: 'I would lay down my life for two brothers or eight cousins.'
- Kin Recognition: Animals are adept at recognizing relatives and exhibit cooperative behaviors accordingly.
- Examples: Vervet monkeys recognize and aid related individuals, showing kin selection dynamics.
Reciprocal Altruism: Cooperation among non-relatives when it’s reciprocated, balancing help and vigilance against cheating.
- Necessary Conditions: Involves memory, individual recognition, and prolonged interactions, typically seen in social vertebrates but also in simpler organisms like bacteria.
- Cheating Detection: Both humans and chimps excel at spotting cheating over spontaneous altruism.
- Game Theory: Studies like the prisoner's dilemma illustrate optimal cooperation and cheating strategies.

Axelrod’s Tournament: Discovered 'Tit for Tat' as the optimal strategy. Key traits: niceness, retaliation, forgiveness, and clarity in play.
Signal Errors: Introduce vulnerabilities in 'Tit for Tat.' 'Forgiving Tit for Tat' can mitigate errors but might be exploited by non-forgiving strategies.
Pavlov Strategy: Continues successful strategies and changes losing ones, showing adaptability.
Field Applications: Examples in vampire bats, stickleback fish, etc., show real-life applications of game theory in animal behavior.
Evolving Complex Behaviors: Real-world examples show complications like role diversification (e.g., lions tolerating certain behaviors due to multi-role interactions).

Tournament vs. Pair Bonding Species:
- Tournament Species: High sexual dimorphism, male-male aggression, high reproductive variability, lesser paternal care. Examples: baboons, peacocks.
- Pair Bonding Species: Low sexual dimorphism, equal parental care, low reproductive variability. Examples: marmosets, tamarins.

Intermediate Position: Humans exhibit traits of both tournament and pair bonding species, leading to diverse mating systems and social behaviors.
Cultural Variability: Different forms of polygamy (economic vs. demographic-driven) and majority of people in monogamous relationships in polygamous cultures.

Integration of Principles: Applying these evolutionary principles helps explain a wide range of social behaviors in animals and humans. Future lectures will expand on these ideas, exploring aspects like aggression, cooperation, and more.