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One last time: haplodiploidy

One last time: haplodiploidy. Leafcutter ant queen + workers. Male leafcutter ant. reproduction. 0.5 of genome from dad X 1.0 = 0.5. 0.5 of genome from mom X 0.5 = 0.25. +. r = 0.75. SEXUAL SELECTION.

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One last time: haplodiploidy

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  1. One last time: haplodiploidy Leafcutter ant queen + workers Male leafcutter ant reproduction 0.5 of genome from dad X 1.0 = 0.5 0.5 of genome from mom X 0.5 = 0.25 + r = 0.75

  2. SEXUAL SELECTION A type of natural selection that acts differently on males and females of the same species Traits that increase mating success are selected for Pheasants

  3. SEXUAL SELECTION Damselflies

  4. SEXUAL SELECTION Sexual dimorphism:male and female have different forms Elephant seals

  5. Why aren’t all species dimorphic? SEXUAL SELECTION

  6. BATEMAN PRINCIPLE # kids # mates SEXUAL SELECTION Dimorphism arises from competition for mates Malesproduce sperm: cheap Females produce eggs: expensive

  7. BATEMAN PRINCIPLE The sex that invests most in reproduction is a limiting resource that opposite sex competes for Female is usually limiting sex (expecially in mammals), but not always

  8. SEXUAL SELECTION Role reversal Greater Painted Snipe

  9. SEXUAL SELECTION Whichis the limiting sex? Pipefish Seahorse Sea dragon

  10. SEXUAL SELECTION Parental care Male may be needed to care for young

  11. SEXUAL SELECTION Sage grouse Peacock

  12. SEXUAL SELECTION 1. Runaway selection: trait initially useful for survival is exaggerated by sexual selection Long-tailed Widowbird

  13. SEXUAL SELECTION 1. Runaway selection: trait initially useful for survival is exaggerated by sexual selection

  14. SEXUAL SELECTION 2. Handicap principle: ornaments show that males are high-quality Ornaments expensive to produce, only males in good condition can have them Ornamental males less likely to have disease

  15. SEXUAL SELECTION Satin bowerbird

  16. OPTIMIZING FITNESS Every trait has costs and benefits Natural selection should favor strategies that lead to higher fitness

  17. OPTIMIZING FITNESS Gulls “mob” predators that approach nest sites

  18. OPTIMIZING FITNESS How daring should the gull be? Daring mobber Benefits of action Units of Fitness Cautious mobber Cost of action 0.5 1 1.5 2 2.5 3 3.5 Distance from predator (m)

  19. OPTIMIZING FITNESS Optimal strategy: Benefits - Costs = Maximum Natural selection should favor optimal strategy

  20. GENE FLOW the movement of genes from one population to another “Hide” allele “Run” allele

  21. TYPES OF SELECTION 1. Directional Frequency Evolutionary change Trait 2. Stabilizing Most common: maintains status quo 3. Disruptive Speciation

  22. DIRECTIONAL SELECTION Darwin’s finches Geospiza fortis Severe drought 1976-1977 Killed plants with small seeds: birds with larger beaks survived better Boag and Grant 1981 10.5 mm 11 mm

  23. STABILIZING SELECTION Human birth weight Extreme light weight and extreme heavy weight both selected against 8 lbs

  24. DISRUPTIVE SELECTION Three-spined sticklebacks Dolph Schluter Descended from common ancestor benthic Selection favored large fish near shore and small fish in open water limnetic Assortative mating led to speciation Assortative mating: Like mates with like; non-random mating

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