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Second Exam One Week from Thursday Covers Chapters 5, 8, 9 , 10, and 11 Lectures 11 to 19 Plus Evolution of Uncaring Hu

Second Exam One Week from Thursday Covers Chapters 5, 8, 9 , 10, and 11 Lectures 11 to 19 Plus Evolution of Uncaring Humanoids Agriculture Global Warming The Vanishing Book of Life on Earth Plastics Intelligent Design?.

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Second Exam One Week from Thursday Covers Chapters 5, 8, 9 , 10, and 11 Lectures 11 to 19 Plus Evolution of Uncaring Hu

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  1. Second Exam One Week from Thursday Covers Chapters 5, 8, 9, 10, and 11 Lectures 11 to 19 Plus Evolution of Uncaring Humanoids Agriculture Global Warming The Vanishing Book of Life on Earth Plastics Intelligent Design?

  2. Population Growth and Regulation S - shaped sigmoidal population growth Verhulst-Pearl Logistic Equation: dN/dt = rN [(K – N)/K] Assumptions, Derivation Density Dependence versus Density Independence Equilibrium, Opportunistic, and Fugitive speciesr-selection versus K-selection (r-K selection Continuum) Correlates of r and K-selection, Bet Hedging Winemiller’s 3-dimensional fish life history surface Population Change versus Population Density Plots Microtine Rodent Population Fluctuations Hudson Bay Fur Company: Snowshoe Hare and Lynx “Cycles”

  3. Sunspot Hypothesis(Sinclair et al. 1993. Am. Nat.) 10 year cycle embedded within 30-50 year periods Maunder minimum: 1645-1715 Three periods of high sunspot maxima: 1751-1787 1838-1870 1948-1993 Canadian Government survey 1931-1948 Hare cycle synchronized across North America Yukon: 5km strip, tree growth rings (N = 368 trees) One tree germinated in 1675 (>300+ years old) Hares prefer palatable shrubs, but will eat spruce leaving dark tree ring marks

  4. Other Food Quality Hypotheses: Microtus (Freeland 1974) palatability <–––> toxic Snowshoe hares: Plant chemical defenses against herbivory (Bryant 1980)

  5. Chitty’s “Genetic Control” Hypothesis Could optimal reproductive tactics be involved in driving population cycles?

  6. Population “Cycles” • Sunspot Hypothesis • Time Lags • Stress Phenomena Hypothesis • Predator-Prey Oscillations • Epidemiology-Parasite Load Hypothesis • Food Quantity Hypothesis • Nutrient Recovery • Other Food Quality Hypotheses • Genetic Control Hypothesis

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

  8. V Net Benefit V

  9. Sexual ReproductionMonoecious versus Diecious Evolution of Sex —> Anisogamy Diploidy as a “fail-safe” mechanism Costs of Sexual Reproduction (halves heritability!) Facultative Sexuality (Ursula LeGuin -- Left Hand of Darkness) 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

  10. Robert Warner No Sex Change Protogyny Protandry Male Female Male Female=Male Female

  11. Why have males? “The biological advantage of a sex ratio that is unbalanced in favor of females is readily apparent in a species with a promiscuous mating system. Since one male could fertilize several females under such a system, survival of a number of males equal to the number of females would be wasteful of food, home sites, and other requirements for existence. The contribution of some of the surplus males to feeding the predators on the population would be economically advantageous. In other words, the eating of the less valuable (to the population) males by predators would tend to reduce the predator pressure on the more valuable females.” — Blair (1960) The Rusty Lizard W. Frank Blair Sceloporus olivaceus

  12. Sex RatioProportion of Males Primary, Secondary, Tertiary, Quaternary Why have males? Fisher’s theory: equal investment in the two sexes Ronald A. Fisher

  13. Comparison of the Contribution to Future Generations of Various Families in Case a in Populations with Different Sex Ratios __________________________________________________________________ Case a Number of Males Number of Females __________________________________________________________________ Initial population 100 100 Family A 4 0 Family C 2 2 Subsequent population (sum) 106 102 CA = 4/106 = 0.03773 CC = 2/106 + 2/102 = 0.03846 (family C has a higher reproductive success) __________________________________________________________________ Note: The contribution of family x is designated Cx.

  14. Comparison of the Contribution to Future Generations of Various Families in Case a in Populations with Different Sex Ratios __________________________________________________________________ Case a Number of Males Number of Females __________________________________________________________________ Initial population 100 100 Family E 0 4 Family C 2 2 Subsequent population (sum) 102 106 CE = 4/106 = 0.03773 CC = 2/106 + 2/102 = 0.03846 (family C has a higher reproductive success) __________________________________________________________________ Note: The contribution of family x is designated Cx.

  15. Comparison of the Contribution to Future Generations of Various Families in Case a in Populations with Different Sex Ratios __________________________________________________________________ Case a Number of Males Number of Females __________________________________________________________________ Initial population 100 100 Family A 4 0 Family C 2 2 Family E 0 4 Subsequent population (sum) 106 106 CA = 4/106 = 0.03773 CC = 2/106 + 2/106 = 0.03773 All three families have equal success CE = 4/106 = 0.03773 __________________________________________________________________ Note: The contribution of family x is designated Cx.

  16. ______________________________________________________________________________________________________________________________________________________ Case b Number of Males Number of Females ____________________________________________________________________________ Initial population 100 100 Family A 2 0 Family B 1 2 Subsequent population (sum) 103 102 CA = 2/103 = 0.01942 CB = 1/103 + 2/102 = 0.02932 (family B is more successful) Initial population 100 100 Family B 1 2 Family C 0 4 Subsequent population (sum) 101 106 CB = 1/101 + 2/106 = 0.02877 CC = 4/106 = 0.03773 (family C is more successful than family B) Natural selection will favor families with an excess of females until the population reaches its equilibrium sex ratio (below). Initial population 100 200 Family B 1 2 Family C 0 4 Subsequent population (sum) 101 206 CB = 1/101 + 2/206 = 0.001971 CC = 4/206 = 0.01942 (family B now has the advantage) _____________________________________________________________________________ Note: The contribution of family x is designated Cx.

  17. Differential Mortality of the sexes during the period of parental care.

  18. Differential Mortality of the sexes during the period of parental care

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