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Life History Patterns Ch.10. Life history patterns = how they reproduce Maturity = age at first reproduction Parity = # of times an organism reproduces Fecundity = # offspring per reproduction Mortality = death rate Parental care. Inverse relationship between fecundity and parental care.
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Life History Patterns Ch.10 • Life history patterns = how they reproduce • Maturity = age at first reproduction • Parity = # of times an organism reproduces • Fecundity = # offspring per reproduction • Mortality = death rate • Parental care
Inverse relationship between fecundity and parental care high ? Parental care low high low fecundity
Inverse relationship between fecundity and parental care high Parental care low high low fecundity
r vs. k selection k-selected r-selected Fewer offspring Slow development Long lived Good competitors Slow dispersers Much parental care Examples?? Trees bears Many small offspring Rapid development Short lived Poor competitors Fast dispersers Little parental care Examples?? Weeds ants r-selected = opportunistic k-selected = equilibrium
altricial vs. precocial • Altricial = helpless and featherless 2-10 eggs per clutch • Precocial = ready to follow parents 8-20 eggs per clutch (clutch = nest of eggs)
Reproduction Plants: Annuals = lives one year Perennials = live more than one year Semelparity = one reproductive effort per lifetime Also called “big bang reproduction,” “programmed death” i.e. agave (century plant), yucca, salmon Iteroparity = more than one reproductive effort per lifetime Senescence = age, causes decline in fecundity
Mating systems • Monogamy = pair bond between one male and one female • Polygamy = one individual forms pair bonds with many others Polygyny = male mates with more than one female Polyandry = female mates with more than one male • Promiscuity = mate with many, no pair bonds
Monogamy Rare in mammals Common in Birds
Polygyny – one male with many females Common in mammals
Polyandry – one female with many males rare female Since females attract mate, they are larger And more colorful than male Wilson’s phalaropes
Promiscuity – no pair bonds Lek = common mating area Prairie Chicken Male sage grouse
Sexual Selection = choice of one sex by another • Sexual Dimorphism = males and females look differently • Color- males more brightly colored • Ornamentation- antlers • Size (if female larger = reverse sexual dimorphism) • Hamilton-Zuk Hypothesis • More brightly colored males have less parasites (healthier)
