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

Lecture # 1722 October 2015

Social BehaviorHermits must have lower fitness than social individualsClumped, random, or dispersed (variance/mean ratio)mobility = motility = vagility (sedentary sessile organisms)Fluid versus Viscous Populations

Use of Space, PhilopatryIndividual Distance, Daily MovementsHome RangeTerritoriality (economic defendability)Resource in short supply

Feeding TerritoriesNesting TerritoriesMating Territories

Sexual ReproductionMonoecious (Hermaphrodites) versus DieciousEvolution of Sex —> AnisogamyDiploidy as a “fail-safe” mechanismCosts 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 competitionheterozygositybiparental origin of many unisexual species

Male Peacock, a victim of female mating preference

Runaway Sexual Selection (Fisher)

Handicap Hypothesis (Zahavi)

Sensory Exploitation Hypothesis (Ryan)

Leks

Alternative mating tactics, Cuckoldry

Satellite males

Internal versus External Fertilization

Ecological Sexual Dimorphisms

Bower birds

Ratites

Bushland tinamou

Sage Grouse Lek

Sage Grouse Female

Male Reproductive Succes in Sage Grouse

Geographic Range of Sage Grouse

Prairie Chicken

Prairie Chicken

Atwater Prairie Chicken

Jacana, Lily pad walker

Dinosaur fossils suggest that male parental care could be ancestral in birds

If so, ratites could have retained the ancestral state

And, if so, then female care and biparental care would be derived conditions

A male of the medium-sized predatory dinosaur Troodon (North America late Cretaceous) brooding a large clutch of eggs. Female archosaurs extract substantial amounts of calcium and phosphorus from their skeletal tissues during egg formation. Histologic examination of cross sections of bones (femur, tibia, and a metatarsal bone) from an adult Troodon found in direct contact with an egg clutch revealed little evidence of bone remodeling or bone resorption,

suggesting that the bones were those of a male. Fossilized remains of Troodon and two other types of dinosaurs found with large clutches of eggs suggest that males, and not females, protected and incubated eggs laid by perhaps several females (Credit: Bill Parsons)

20

111

3

4

56

7

916

11

13

1514

Red-eyed Vireo

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

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”) 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 44.8Father x Stepmother 0.25 17 9.8Mother x Stepfather 0.25 16 9.2Son x Nonrelative 0.25 18 10.3Brother x Nonrelative 0.25 12 6.9Grandfather x Grandmother 0.25 5 2.9Half brother x Nonrelative 0.13 3 1.7Uncle x Nonrelative 0.13 2 1.1Grandmother x Nonrelative 0.13 1 0.6Grandson x Nonrelative 0.13 1 0.6Great grandfather x Nonrelative 0.13 1 0.6Nonrelative x Nonrelative 0.0 20 11.5Total 174 100.0__________________________________________________________________* r = coefficient of relatedness.

––-><---- 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

3. Keep on moving

4. Mixed species flocks, fake alarm calls