Chapter 8: Life History Patterns (Exam 1)

traits that describe the life cycle of an organism (reproductive rate, maturity rate, lifespan etc.)

one parent passes on a complete set of genetic info (binary fission) less genetic variation-no mate needed

2 parent s each pass on 1/2 set of genetic info reproduction costly but greater variation

development of an individual from an unfertilized egg (lizard)

has both male and female reproductive structures at the same time

spend part of their life cycle as a female and part as male (mollusks, echinoderms)

possessing both male and female reproductive organs

monogamy polygamy polygyny polyandry

1 female/1 male w/long lasting bond (birds)

2 or more mates (cats)

form of polygamy where 1 male pairs w/2 or more females (moose)

form of polygamy which 1 female pairs w/2 or more males (sand pipper)

mate choice and competition for mates among individuals may lead to selection for particular traits

members of 1 sex consistently choose mates of the opposite sex based on certain traits

individuals of one sex compete among themselves for mates

not directly involved in reproduction (differences in phenotypes)

members of opposite sex find a trait desirable "runaway" because over time it would facilitate the development of greater preference and more pronounced traits until the cost of trait balances reproductive benefit of possessing it

increase of reproductive effort may benefit offspring but can reduce survivorship of the parent

the amount of energy allocated to reproduction

number of offspring per reproductive eent

environmental variation yearly & seasonal variation latitudinal and elevational variation (clines)

having only a single reproductive effort in a lifetime over one short period of time

many reproductive events per lifetime

unpredictable environments (lean forage) delay reproduction, survival of parents, abandonment of the eggs or offspring

reproductively active as larvae (tiger salamander)

short incubation times often result in young being born in helpless state, which requires greater parental care

longer incubation periods can produce young which require considerably less parental care

placental mammals marsupials oviparous ovoviviparous viviparous

The retention in an adult organism of the juvenile features of its evolutionary ancestors.

give birth to live young (r or precocial) who received their nourishment during embryonic development from allartoic placenta

give birth to live young who complete their embryonic development inside a maternal pouch called marsuprum which contains nipples for nursing

lay eggs w/little or no other embryonic development w/in the mother (yolk sac provides nourishment)

young develop w/in eggs or membrane sacs that remain w/in the females body until they hatch (or are able to)

birth to live young (reptiles, fish)

characteristics exhibited by a species are the product for evolution and should reflect adaptations to the prevailing environmental conditions under which natural selection occurred

(typical (short lived)), high reproductive rates at low population densities, rapid development, small body size, large # of offspring (but low survival rate), minimal parental care

competitive species with stable populations of long-lived individual can cope w/physical and biotic pressures

low offspring survival, low birth rates, early maturity

low offspring survival, high birth rates, late maturity

high offspring survival, low birth rates, late maturity

index of reproductive effort

Hatching that occurs at the same time or nearly the same time, usually within one calendar day (compare to Asynchronous Hatching).

A hatching that does not occur at the same. It may take place over two to three calendar days. Parrots hatch Asynchronously while ducks and chickens hatch Synchronously.