Evolution and Adaptation I. The Modern Synthesis II. Beyond the Synthesis III. Life History Adaptations IV. Sex and Evolution V. Types of Selection A. Natural Selection B. Sexual Selection C. Kin Selection and the Evolution of Cooperative and Antagonistic Behavior

…bees make me sad… A. Darwin’s Dilemma

Social Behaviors, like all adaptations, must be evaluated on a cost/benefit analysis

B. Kin Selection 1. Inclusive Fitness 1/2 1 several relatives have more of YOUR genes, cumulatively, than YOU do! ½ + ½ + ½ > 1

1/2 1 B. Kin Selection 1. Inclusive Fitness

If I save myself… 1/2 1 I save one “set” of my genes… XX XX X X AAAAAAAAA !!!!! 1

If I save my relatives… I save 1.5 sets of my genes. If this has a genetic basis, selection will favor altruism among relatives. 1/2 1 …ow… 1/2 What a guy!

B. Kin Selection 2. Haplodiploidy and Social Insects …bees make me sad… W. D. Hamilton – 1964 Coined the term “Kin Selection” and explained the selection for sterility – haplodiploidy in social insects

C. Altruism 1. Among relatives – a function of kin selection White-fronted bee-eaters

C. Altruism 1. Among relatives – a function of kin selection Tiger salamander

C. Altruism 2. Among non-relatives Scenario 1: Payoff to hawks is always greater than payoff to doves, regardless of density. Even though all doves is better for the group, it is not an ESS… it can be ‘invaded’ by hawks. All hawks IS an EES, though, because doves always at disadvantage and can’t increase in population.

C. Altruism 2. Among non-relatives Book diagram is wrong… Scenario 2: Here, the cost of competition among hawks is high, so as hawk density increases, payoff to hawks decline rapidly. A population of all hawks is not an ESS now – it can be invade by doves. There is a stable equilibrium in which hawks and doves are maintained in the population.

C. Altruism 2. Among non-relatives Direct Reciprocity/Reciprocal Altruism/Tit for Tat Nowak, M. A Five rules for the evolution of cooperation. Science 314:

C. Altruism 2. Among non-relatives Indirect Reciprocity – “Reputation” Nowak, M. A Five rules for the evolution of cooperation. Science 314: “watcher”

C. Altruism 2. Among non-relatives Network Reciprocity - Nowak, M. A Five rules for the evolution of cooperation. Science 314:

C. Altruism 2. Among non-relatives Group Selection Nowak, M. A Five rules for the evolution of cooperation. Science 314:

C. Altruism 2. Among non-relatives Group Selection Nowak, M. A Five rules for the evolution of cooperation. Science 314: Pseudomonas flourescens Colonies with high concentration of mat-builders (expensive proteins) float; if cheaters increase in number, colony sinks and dies.

Vogel, G Evolution of the golden rule. Science 303: Game: Give one monkey a pebble. If it gives it back (co- operation), it gets a cucumber slice.

Vogel, G Evolution of the golden rule. Science 303: Game: Give one monkey a pebble. If it gives it back (co- operation), it gets a cucumber slice. Repeat with a second monkey, in view of the first, but give the second monkey a grape (better reward). GRAPE?… what the

Vogel, G Evolution of the golden rule. Science 303: Fair trade. Capuchin monkeys refuse to cooperate when they see a comrade receive a better reward for the same task. Game: Give one monkey a pebble. If it gives it back (co- operation), it gets a cucumber. Repeat with a second monkey, in view of the first, but give the second monkey a grape (better reward). First monkey will no longer return the pebble for a cucumber. KEEP your CUCUMBER!!

Chimps helping strangers - pbio www.plosbiology.org/article/info%3Adoi%2F %2Fjournal. pbio wild-born chimps (orphaned) – Uganda Two novel experimenters struggle over stick, thrown in cage Experimenter reaches for stick Does chimp help and get the stick in 60 sec?

Chimps helping strangers - yes, as often as 18 month old children if the experimenter reaches for it.

Chimps helping strangers - Still, humans at the sanctuary provide the chimpanzees food and shelter, so helping people out could simply be in their best interests.

Chimps helping strangers unrelated chimps ‘trained’ to use a mechanism in a pre-test.

Both the target and the distracter door were held shut by chains. subject (S) could release the chain of the target door. In the experimental condition, food was placed in the target room (subject could help) by releasing the target chain. In the control condition, food was placed in the distracter room, so that the recipient would try to open the distracter door. In this situation, it was irrelevant (with respect to the recipient's attempt to open the distracter door) whether the subject released the target chain. The target measure in both conditions was whether the subject released the target chain. (from Warneken, PLOS 2007). 3 acted as recipients and 6 as subjects – 10 trials for each pairing; 5 experimental and 5 controls (banana in ‘distractor’ room). pbio #pbio sv003

Mean percentage of trials with target behavior (releasing the target chain) by condition. Error bars represent SEM. Each subject was tested in both conditions in a within-subject comparison. (Warneken, PLOS 2007). Subjects pull bar for recipient to access food significantly more often than the control (p < 0.025). Difference increased over trials.

D. Conflicts within Families

2. Parent-Parent IGFII gene – stimulates growth On in males, stimulating the growth of their own offspring; off in females, as she bears the cost of growing embryos and all are hers.

D. Conflicts within Families 2. Parent-Parent IGFII inhibitor gene – slows growth Off in males, stimulating the growth of their own offspring; on in females, as she bears the cost of growing embryos and all are hers.

D. Conflicts within Families 2. Parent-Offspring Parent’s potential for future reproduction may favor them investing in survival rather than parental care.

D. Conflicts within Families 2. Parent - offspring Selection can favor parents that abort care of current offspring to improve survival and future reproductive success…

D. Conflicts within Families 2. Parent - offspring Selection can favor parents that abort care of current offspring to improve survival and future reproductive success…

D. Conflicts within Families 2. Sibling - sibling

D. Conflicts within Families 2. Sibling - sibling