Unformatted text preview: ; future reprod.
inﬂuenced by survival rate
Life History Theory:
when will selection favor which side of the balance?
offspring number vs offspring quality early reproduction vs. late reproduction Selection on life histories:
risk of predation in guppies size at maturity low pred.: larger size investment /
event above waterfalls: low predation
below waterfalls: high predation offspring # lower investment high pred.: smaller size higher investment offspring size fewer, larger offspring
more, smaller offspring Selection on life histories:
risk of predation Cod
take large numbers of the oldest/largest individuals;
select for early maturation (at smaller sizes) Selection on life histories:
risk of death
lifespan 5-6 years;
females begin breeding at age 2; 1 litter/yr epidemic of contagious tumors:
tumors affect adults; kill within months;
before: 75% of females bred 1+ times;
after: 35% of females bred 1+ times
reduced adult survival wil...
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