The Evolution of Cooperation

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another?

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary:

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary: among genes in a genome

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary: among genes in a genome among organelles in a cell

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary: among genes in a genome among organelles in a cell among cells in a multicellular organism

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary: among genes in a genome among organelles in a cell among cells in a multicellular organism among organisms in a social group

The Evolution of Cooperation I. Issue - How can cooperation evolve, especially if by cooperating, an entity reduces its own immediate fitness in sacrifice to that of another? - However, cooperation is OBSERVED and necessary: among genes in a genome among organelles in a cell among cells in a multicellular organism among organisms in a social group between species in symbiotic relationships

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (Hamilton, 1964)

A. Kin Selection r > c/b White-fronted bee-eaters

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) Nowak, M. A. 2006. Five rules for the evolution of cooperation. Science 314:1560-1563.

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - prisoners dilemma B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - prisoners dilemma So, cooperation pays...but blind sacrifice does not! B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - in the "repeated prisoner's dilemma": B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - in the "repeated prisoner's dilemma": - it's adaptive to cooperate if there are repeated interactions with the same partner B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - in the "repeated prisoner's dilemma": - it's adaptive to cooperate if there are repeated interactions with the same partner - it works by 'tit for tat' or 'hold if it pays' (if you start on cooperate) B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - in the "repeated prisoner's dilemma": - it's adaptive to cooperate if there are repeated interactions with the same partner - it works by 'tit for tat' or 'hold if it pays' (if you start on cooperate) B Stays Silent B Betrays A Stays Silent both get 6 months A gets 10 years; B goes free A Betrays B gets 10 years; A goes free both get 2 years - cooperation can evolve only if w > c/b .... if the frequency of encounter exceeds the cost/benefit ratio of the altruistic act. If this is the case, you may profit in the future if the act is reciprocated (and if w is high, then there is good chance it will be)

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - Mutualisms: both partners have increased fitness, relative to other members of their species, by interacting with another species.

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - Mutualisms: both partners have increased fitness, relative to other members of their species, by interacting with another species. - Positive feedback can enhance the dependency between partners

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) - Mutualisms: both partners have increased fitness, relative to other members of their species, by interacting with another species. - Positive feedback can enhance the dependancy between partners Atta cephalotes, the "leaf cutter" ants, farm and eat a species of fungus that lives nowhere else now.

Acacia and Acacia ants

Corals and zooxanthellae Aphid farming by ants Frugivory Gleaners Pollination Protozoans in Termites

II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) C. Indirect Reciprocity – “reputation” “watcher” Nowak, M. A. 2006. Five rules for the evolution of cooperation. Science 314:1560-1563.

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) C. Indirect Reciprocity (Nowak 1998) - In large populations (humans), the frequency of encounter may be low, and the relationship is asymmetric (one person CAN help, the other may never be able to).

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) C. Indirect Reciprocity (Nowak 1998) - In large populations (humans), the frequency of encounter may be low, and the relationship is asymmetric (one person CAN help, the other may never be able to). - Helping establishes a good reputation; and increases the chance that others (not the direct beneficiaries) will help us if we need it.

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). A. Kin Selection (W. D. Hamilton) B. Direct Reciprocity (Trivers 1971) C. Indirect Reciprocity (Nowak 1998) - In large populations (humans), the frequency of encounter may be low, and the relationship is asymmetric (one person CAN help, the other may never be able to). - Helping establishes a good reputation; and increases the chance that others (not the direct beneficiaries) will help us if we need it. - People who are observed to be more helpful are more likely to be helped.

- Even in other species... Bshry 2006 - Cleaner Wrasse - wrasse eat parasites off "client" fish... but they can cheat and eat mucous, which is bad for the client fish.

- Even in other species... Bshry 2006 - Cleaner Wrasse - wrasse eat parasites off "client" fish... but they can cheat and eat mucous, which is bad for the client fish. - Client fish observe wrasses, and prefer the wrasses that don't cheat

- Even in other species... Bshry 2006 - Cleaner Wrasse - wrasse eat parasites off "client" fish... but they can cheat and eat mucous, which is bad for the client fish. - Client fish observe wrasses, and prefer the wrasses that don't cheat - AND, when WATCHED, wrasses cheat less and cooperate more...

- Even in other species... Bshry 2006 - Cleaner Wrasse - wrasse eat parasites off "client" fish... but they can cheat and eat mucous, which is bad for the client fish. - Client fish observe wrasses, and prefer the wrasses that don't cheat - AND, when WATCHED, wrasses cheat less and cooperate more... - so wrasses cooperate with current clients to gain favor (reputation) with others that are observing. - cooperation can only evolve IF q > c/b, where: q = prob. of knowing someone's reputation

C. Indirect Reciprocity – “reputation” D. Network Reciprocity http://www.youtube.com/watch?v=frpp6DjCaJU Nowak, M. A. 2006. Five rules for the evolution of cooperation. Science 314:1560-1563.

C. Indirect Reciprocity – “reputation” D. Network Reciprocity E. Group Selection Nowak, M. A. 2006. Five rules for the evolution of cooperation. Science 314:1560-1563.

E. Group Selection Nowak, M. A. 2006. Five rules for the evolution of cooperation. Science 314:1560-1563. Pseudomonas flourescens Colonies with high concentration of mat-builders (expensive proteins) float; if cheaters increase in number, colony sinks and dies.

E. Group Selection “givers and takers” and Evolutionarily Stable Strategies 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 ESS, though, because doves always at disadvantage and can’t increase in population.

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. E. Group Selection “givers and takers” and Evolutionarily Stable Strategies c

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). Conclusions - cooperation can evolve as a result of selection; even among unrelated entities (symbioses) - when cooperation occurs at one level, it creates a new level of organization... cells cooperate and ORGANISMS are produced... organisms cooperate and SOCIAL UNITS are produced. - Cooperation allows specialization, and creates diversity at several levels

Vogel, G. 2004. Evolution of the golden rule. Science 303:1128-1131. Game: Give one monkey a pebble. If it gives it back (co-operation), it gets a cucumber slice.

Vogel, G. 2004. Evolution of the golden rule. Science 303:1128-1131. GRAPE?… what the $%#@@!! 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).

Vogel, G. 2004. Evolution of the golden rule. Science 303:1128-1131. 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!! Fair trade. Capuchin monkeys refuse to cooperate when they see a comrade receive a better reward for the same task.

Chimps helping strangers - http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0050184 36 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? How about a child? Chimp Child

Chimps helping strangers - http://www.livescience.com/animals/070625_chimp_altruism.html yes, as often as 18 month old children if the experimenter reaches for it.

Chimps helping strangers - http://www.livescience.com/animals/070625_chimp_altruism.html 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 - http://www.livescience.com/animals/070625_chimp_altruism.html 9 unrelated chimps ‘trained’ to use a mechanism in a pre-test. They remove the peg, and then can walk around the corner, through the newly opened port, and get the food.

Chimp helping chimp 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).

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.

The Evolution of Cooperation Conflicts within Families

The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). III. Conflicts A. Parent vs. Offspring Parent’s potential for future reproduction may favor them investing in survival rather than parental care.

D. Conflicts within Families The Evolution of Cooperation I. Issue II. Mechanisms (Nowak, 2006, Science). III. Conflicts A. Parent vs. 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

IGFII gene – stimulates growth B. 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.

IGFII inhibitor gene – slows growth B. 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.

C. Sibling - sibling

B. Sibling - sibling

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition - within both populations, those that are competing within AND between species are at an energetic and reproductive disadvantage.

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition - within both populations, those that are competing within AND between species are at an energetic and reproductive disadvantage. - competititive exclusion

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition - within both populations, those that are competing within AND between species are at an energetic and reproductive disadvantage. - competititive exclusion - niche partitioning

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition - within both populations, those that are competing within AND between species are at an energetic and reproductive disadvantage. - competititive exclusion - niche partitioning

Conflicts.... I. Among Relatives II. Among Non-Relatives A. Interspecific Competition - within both populations, those that are competing within AND between species are at an energetic and reproductive disadvantage. - competititive exclusion - niche partitioning; character displacement Both species benefit by reducing the interaction; once it is reduced, there is no benefit to reestablish the interaction.