Life History Patterns Ch 10 Life history patterns

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 Parental care high ? low high low fecundity

Inverse relationship between fecundity and parental care Parental care high low fecundity

r vs. k selection r-selected k-selected Many small offspring Rapid development Short lived Poor competitors Fast dispersers Little parental care Fewer offspring Slow development Long lived Good competitors Slow dispersers Much parental care Examples? ? Weeds ants Examples? ? Trees bears 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)

Territorial Behavior

Calling

Chasing

Fighting

Sibling Competition