One last time: haplodiploidy

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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
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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
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SEXUAL SELECTION
Damselflies
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SEXUAL SELECTION
Sexual dimorphism male and female have different
forms
Elephant seals
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SEXUAL SELECTION
Why arent all species dimorphic?
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(No Transcript)
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SEXUAL SELECTION
Dimorphism arises from competition for mates
Males produce sperm cheap
Females produce eggs expensive
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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
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SEXUAL SELECTION
Role reversal
Greater Painted Snipe
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SEXUAL SELECTION
Which is the limiting sex?
Pipefish
Seahorse
Sea dragon
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SEXUAL SELECTION
Parental care
Male may be needed to care for young
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SEXUAL SELECTION
Sage grouse
Peacock
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SEXUAL SELECTION
1. Runaway selection trait initially useful for
survival is exaggerated by sexual selection
Long-tailed Widowbird
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SEXUAL SELECTION
1. Runaway selection trait initially useful for
survival is exaggerated by sexual selection
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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
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SEXUAL SELECTION
Satin bowerbird
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OPTIMIZING FITNESS
Every trait has costs and benefits
Natural selection should favor strategies that
lead to higher fitness
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OPTIMIZING FITNESS
Gulls mob predators that approach nest sites
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OPTIMIZING FITNESS
How daring should the gull be?
Daring mobber
Benefits of action
Units of Fitness
Cautious mobber
Cost of action
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2
3
1.5
2.5
3.5
0.5
Distance from predator (m)
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OPTIMIZING FITNESS
Optimal strategy Benefits - Costs Maximum
Natural selection should favor optimal strategy
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GENE FLOW
the movement of genes from one population to
another
Hide allele
Run allele
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TYPES OF SELECTION
1. Directional
Frequency
Evolutionary change
Trait
2. Stabilizing
Most common maintains status quo
3. Disruptive
Speciation
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DIRECTIONAL SELECTION
Darwins 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
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STABILIZING SELECTION
Human birth weight
Extreme light weight and extreme heavy weight
both selected against
8 lbs
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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