Second Exam: Thursday 29 October 2015 Covers Chapters 5, 8, 9, 10, and 11 Lectures 10 to 19 plus Agriculture Global Warming The Vanishing Book of Life on Earth Plastics Intelligent Design? The Weakest Link Technology Economics Lecture # October 2015

200 mph winds -- Strongest hurricane in 50 years

Intersexual vs. intrasexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle of the sexes” Cuckoldry —> jealousy Desertion —> Mating Rituals, Complex Courtship Sex that invests most is most choosy about mates Natural selection produces a correlation between male genetic quality and female preference “Sexy son” phenomenon (females cannot afford to mate with males that are not attractive to other females)

Male Reproductive Success in Sage Grouse

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 Prisoner B Stays SilentPrisoner 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 yearsBoth serve two years

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

Evolution of Self Deceit Subconscious mind Polygraph playback experiments

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 00 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 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)

Brown Hydra Green Hydra

Nudibranchs Green sea slug Hydra

Runaway Sexual Selection (Fisher) Handicap Hypothesis (Zahavi) Leks Sensory Exploitation Hypothesis Internal versus External Fertilization Alternative mating tactics Satellite males Ecological Sexual Dimorphisms Ratites (bushland tinamou) Bower birds Spiteful behavior

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 00 Neither party affects the other __________________________________________________________________

Intraspecific competition (between individuals within spp.) Interspecific competition (between members of different spp.) Exploitation competition (resource depression) Interference competition (direct antagonistic encounters)

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 —————————————————>

Euglossine bees Orchid fragrances (epiphytes) Male bees use orchid chemicals as base for production of pheromones to attract female bees (travel up to 23 km) pollinate rare and diverse orchids, allowing sparsely distributed plants to occur at astonishing low densities Dan Janzen

Heliconius tropical butterflies get amino acids from pollen Larry Gilbert

Various Aspects of the Association of Cattle Egrets with Cattle ________________________________________________________ Number of Number Percent Associated Egrets Category of Cattle Cattle Expected Observed ___________________________________________________________________ Grazing in sun Grazing in shade Standing in sun Standing in shade Lying in sun Lying in shade Walking ______________________ Total ________________________________________________________

Various Aspects of the Association of Cattle Egrets with Cattle ______________________________________________________________________ Number of Times Mean Count Was Higher Number Than for Opposite Number of Per Minute Egret Associated Egrets ______________________________________________________________________ Feedings, N = 84 Associated Nonassociated Steps, N = 62 Associated Nonassociated Feeding/step, N = 59 Associated Nonassociated __________________________________________________________ Harold Heatwole

Interspecific Competition leads to Niche Diversification Two types of Interspecific Competition: Exploitation competition is indirect, occurs when a resource is in short supply by resource depression Interference competition is direct and occurs via antagonistic encounters such as interspecific territoriality or production of toxins

Direct versus Indirect Interactions Exploitation vs. Interference competition Apparent Competition Competitive Mutualism Facilitation Food Chain Mutualism Trophic Cascades (top-down, bottom up) Complex Population Interactions (Colwell ’ s Plant-Pollinator System) Mutualisms Euglossine bees and orchids Heliconius butterflies (larval nitrogen reserves) Cattle Egret Commensalism Gause ’ s competition lab experiments

Competitive Exclusion Georgii F. Gause

Coexistence of two species of Paramecium G. F. Gause

Outcome of Competition Between Two Species of Flour Beetles _______________________________________________________________________________ Relative Temp. Humidity Single Species (°C) (%) Climate Numbers Mixed Species (% wins) confusum castaneum _______________________________________________________________________________ Hot-Moistconfusum = castaneum Hot-Dryconfusum > castaneum Warm-Moistconfusum castaneum Cold-Moistconfusum castaneum100 0 _______________________________________________________________________________

Recall the Verhulst-Pearl Logistic Equation dN/dt = rN [(K – N)/K] = rN {1– (N/K)} dN/dt = rN – rN (N/K) = rN – {(rN 2 )/K} dN/dt = 0 when [(K – N)/K] = 0 [(K – N)/K] = 0 when N = K dN/dt = rN – (r/K)N 2

Inhibitory effect of each individual On its own population growth is 1/K Assumes linear response to crowding, instant response (no lag), r and K are fixed constants

S - shaped sigmoidal population growth Verhulst-Pearl Logistic

Lotka-Volterra Competition Equations competition coefficient  ij = per capita competitive effect of one individual of species j on the rate of increase of species i dN 1 /dt = r 1 N 1 ({K 1 – N 1 –  12 N 2 }/K 1 ) dN 2 /dt = r 2 N 2 ({K 2 – N 2 –  21 N 1 }/K 2 ) Isoclines: (K 1 – N 1 –  12 N 2 )/K 1 = 0 when N 1 = K 1 –  12 N 2 (K 2 – N 2 –  21 N 1 )/K 2 = 0 when N 2 = K 2 –  21 N 1 Alfred Lotka Vito Volterra