Second Exam: Thursday 2 April 2015 Covers Chapters 5, 8, 9, and 10 Lectures 10 to 19 plus Agriculture Global Warming The Vanishing Book of Life on Earth Plastics Intelligent Design? The Weakest Link Technology Economics

Social Behavior Hermits must have lower fitness than social individuals Clumped, random, or dispersed (variance/mean ratio) mobility = motility = vagility (sedentary sessile organisms) Fluid versus Viscous Populations Use of Space, Philopatry Individual Distance, Daily Movements Home Range Territoriality (economic defendability) Resource in short supply Feeding Territories Nesting Territories Mating Territories

Sexual Reproduction. Monoecious (Hermaphrodites) versus Diecious Sexual Reproduction Monoecious (Hermaphrodites) versus Diecious Evolution of Sex —> Anisogamy Diploidy as a “fail-safe” mechanism Costs of Sexual Reproduction (halves heritability!) Facultative Sexuality (Cladocera, Daphnia) Protandry <—> Protogyny (Social control) Parthenogenesis (unisexual species) Possible advantages of sexual reproduction include: two parents can raise twice as many progeny mix genes with desirable genes (enhances fitness) reduced sibling competition heterozygosity biparental origin of many unisexual species

Four Possible Situations Involving an Individual’s Behavior and Its Influence on a Neighbor __________________________________________________________________ Neighbor(s) Gain Neighbor(s) Lose Individual Gains Pseudo-altruistic behavior Selfish behavior (kin selection) (selected for) Individual Loses True altruistic behavior Mutually disadvanta- (counterselected) geous behavior (counterselected) _________________________________________________________________

W. D. Hamilton (1964). Kin Selection. Inclusive Fitness W. D. Hamilton (1964) Kin Selection Inclusive Fitness Hamilton’s rule: r n b – c > 0 r = coefficient of relatedness n = number of relatives that benefit b = benefit received by each recipient c = cost suffered by donor r n b > c “Adaptive Geometry of a Selfish Herd”

“Adaptive Geometry of a Selfish Herd”

Eusocial Insects. Hymenoptera (“thin wings”) Eusocial Insects Hymenoptera (“thin wings”) Ants, bees, wasps, hornets Workers are all females Haplodiploidly Isoptera (“same wings”) Termites (castes consist of both sexes) Endosymbionts Parental manipulation Cyclic inbreeding

White-Fronted Bee Eaters, Kenya

Helpers at the Nest in White-Fronted Bee Eaters in Kenya __________________________________________________________________ Breeders r* Number of Cases % Cases Father x Mother 0.5 78 44.8 Father x Stepmother 0.25 17 9.8 Mother x Stepfather 0.25 16 9.2 Son x Nonrelative 0.25 18 10.3 Brother x Nonrelative 0.25 12 6.9 Grandfather x Grandmother 0.25 5 2.9 Half brother x Nonrelative 0.13 3 1.7 Uncle x Nonrelative 0.13 2 1.1 Grandmother x Nonrelative 0.13 1 0.6 Grandson x Nonrelative 0.13 1 0.6 Great grandfather x Nonrelative 0.13 1 0.6 Nonrelative x Nonrelative 0.0 20 11.5 Total 174 100.0 * r = coefficient of relatedness.

Reciprocal Altruism (Trivers 1971) Donor Recipient Small costs, large gains, reciprocated Sentinels Robert Trivers Biological basis for our sense of justice? Friendship, gratitude, sympathy, loyalty, betrayal, guilt, dislike, revenge, trust, suspicion, dishonesty, hypocrisy Reciprocal Altruism (Trivers 1971) ––-> <----

Selfish caller Hypotheses. 1. Full up “I see you”. 2. Mass pandemonium Selfish caller Hypotheses 1. Full up “I see you” 2. Mass pandemonium 3. Keep on moving 4. Mixed species flocks, fake alarm calls

Game Theoretic Approaches. Costs versus benefits of behaviors Game Theoretic Approaches Costs versus benefits of behaviors “tit for tat” strategy can lead to cooperation (“the future casts a long shadow back on the present” -- Axelrod) Evolutionarily stable strategies = ESS (a tactic that when present in a population, cannot be beaten) John Maynard Smith

Game Theoretic Approaches Prisoner's dilemma: Two suspects, A and B, are arrested by the police. The police have insufficient evidence for a conviction, and, having separated both prisoners, each of them is offered the same deal: if one testifies for the prosecution against the other and the other remains silent, the betrayer goes free and the silent accomplice receives the full 10-year sentence. If both stay silent, the police can sentence both prisoners to only six months in jail for a minor charge. If each betrays the other, each will receive a two-year sentence. Each prisoner must make the choice of whether to betray the other or to remain silent. But neither prisoner knows for sure what choice the other prisoner will make. So the question this dilemma poses is: What will happen? How will the prisoners act?

Prisoner's Dilemma http://plato.stanford.edu/entries/prisoner-dilemma/ Prisoner B Stays Silent Prisoner B Betrays Prisoner A Stays Silent Both serve 6 months Prisoner A serves 10 years Prisoner B goes free Prisoner A Prisoner A goes free Betrays Prisoner B serves 10 years Both serve two years http://plato.stanford.edu/entries/prisoner-dilemma/

Evolution of Self Deceit. Subconscious mind Evolution of Self Deceit Subconscious mind Polygraph playback experiments Fool Yourself The Better to Fool Others

Evolution of Self Deceit. Subconscious mind Evolution of Self Deceit Subconscious mind Polygraph playback experiments Fool Yourself The Better to Fool Others

Evolution of Self Deceit. Subconscious mind Evolution of Self Deceit Subconscious mind Polygraph playback experiments Fool Yourself The Better to Fool Others

Summary of Direct Pairwise Interactions Between Two Populations __________________________________________________________________________ Species Type of Interaction A B Nature of Interaction Competition – – Each population inhibits the other Predation, parasitism, + – Population A, the predator, parasite, and Batesian mimicry or mimic, kills or exploits members of population B, the prey, host, or model Mutualism, + + Interaction is favorable to both (can Müllerian mimicry be obligatory or facultative) Commensalism + 0 Population A, the commensal, benefits whereas B, the host, is not affected Amensalism – 0 Population A is inhibited, but B is unaffected Neutralism 0 0 Neither party affects the other __________________________________________________________________

Indirect Interactions Darwin — Lots of “Humblebees” around villages

Indirect Interactions Darwin — Lots of “Humblebees” around villages bees —> clover

Indirect Interactions Darwin — Lots of “Humblebees” around villages bees ——> clover

Indirect Interactions Darwin — Lots of “Humblebees” around villages mice ——o bees ——> clover

Indirect Interactions Darwin — Lots of “Humblebees” around villages cats —o mice ——o bees ——> clover

Indirect Interactions Darwin — Lots of “Humblebees” around villages spinsters —> cats —o mice —o bees —> clover

Indirect Interactions Darwin — Lots of “Humblebees” around villages spinsters —> cats —o mice —o bees —> clover —> beef

Indirect Interactions Darwin — Lots of “Humblebees” around villages spinsters —> cats —o mice —o bees —> clover —> beef —> sailors

Indirect Interactions Darwin — Lots of “Humblebees” around villages spinsters —> cats —o mice —o bees —> clover —> beef —> sailors —> naval prowess

Indirect Interactions Darwin — Lots of “Humblebees” around villages spinsters —> cats —o mice —o bees —> clover —> beef —> sailors —> naval prowess Path length of seven! Longer paths take longer (delay) Longer paths are also weaker, but there are more of them —————————————————>

Indirect Interactions Trophic “Cascades” Top-down, Bottom-up

Competitive Mutualism

Complex Population Interactions Rob Colwell

Mutualistic Interactions and Symbiotic Relationships Mutualistic Interactions and Symbiotic Relationships Mutualism (obligate and facultative) Termite endosymbionts Commensalisms (Cattle Egrets) Examples: Bullhorn Acacia ant colonies (Beltian bodies) Caterpillars “sing” to ants (protection) Ants tend aphids for their honeydew, termites cultivate fungi Bacteria and fungi in roots provide nutrients (carbon reward) Bioluminescence (bacteria) Endozoic algae (Hydra), “kidnapped” chloroplasts Endosymbiosis (Margulis) mitochondria & chloroplasts Birds on water buffalo backs, picking crocodile teeth Figs and fig wasps (pollinate, lay eggs, larvae develop)

Nudibranchs Green sea slug Hydra