1. KEY CONCEPT Social behaviors enhance the benefits of living in a group.

2. Living in groups also has benefits and costs.
Social behaviors evolve when the benefits of group living outweigh its costs.
benefits: improved foraging, reproductive assistance, reduced chance of predation
costs: increased visibility, competition, disease contraction
Group living requires learning social structure and membership.

3. Social behaviors are interactions between members of the same or different species.
Animals use communication to keep in contact.
visual
sound
touch
chemical (pheromones)

4. Courtship displays are used to evaluate the fitness of a potential mate.

5. Defensive behaviors are used to protect the individual and/or the group.

6. Some behaviors benefit other group members at a cost to the individual performing them.
There are many types of helpful social behavior.
cooperation
reciprocity
altruism

7. In altruism, an individual reduces its own fitness to help other members of its social group.
inclusive fitness
kin selection

8. Eusocial behavior is an example of extreme altruism.
Eusocial species live in large groups of mostly nonreproductive individuals.
haplodiploid species: social insects (wasps, bees, ants)
Minor worker
Major worker
Queen
diploid species: termites, snapping shrimp, naked mole rats
Eusocial behaviors likely evolve by kin selection.

9. Naked mole rats