Ecology Exam 3

life history

schedule of an organism’s growth, development, reproducion, and survival

• parental care

• size and number of offspring

• life span and reproductive span

• semel-, iteroparity

Darters

live in benthic habitats and are freshwater fish

• groups of 175

• have similairites in habitat and morphology but have differences in life history

• trade off between egg size and fecundity (high fecundity means smaller eggs)

fecundity

number of gametes, seeds or propagules produced

principle of allocation

energy used for one thing can not be used to do other things

darter egg trade-off

can either produce large eggs or many eggst but not both

• gene flow is greater in species that lay small (and many) eggs

relationship between seed size

larger seeds produce fewer seeds

• mode of seed dispersal depends on seed size (important to establish its range)

how fast do plants grow

larger seeds grow faster and bigger

• bigger seed is a larger starter pack of resources

eggs in a clutch

parents were able to provide for up to 7 eggs (8 was too much)

flowering time

number of days from germination to first production of flowers (birth to sexual maturity)

• needs to align with pollinators, mates, and environmental conditions

trade-off between survivorship and reproductive effort

risky: organisms will reproduce as young as possible, and maximize its investment in reproduction

safe: organisms delay reproduction to an older age, and invest in its own growth and maintenance

life history characteristics

• growth rate and carrying capacity

• survival, fecundity, and age at reproduction

r-selected species

• small and fast lifestyle

• weedy species good a moving into new enviornments after a disturbance

• operates fast in exponential part of growth curve

• many, small offspring

k-selected species

• big and slow lifestyle

• good competitors that eventually dominate in low-distrubance environments

• operate in hihg-density but slow logistic part of the growth curve

• few, large offspring

stress-tolerant plants

• efficient at using resources

• adaptations for temperature and water regulation

• allocate to maintenance

competitive plants

• when disturbance and stress are low and species are the best competitors

• allocate to growth

ruderals

• weedy

• move in quickly to competitor-free, available habitat

• allocate to reproduction

distribution shifts and climate change

climate change drives shifts in distributional ranges of many species

• animal dispersal is related to life history characteristics

shifting species

those who are younger, smaller, and smaller at maturity tend to shift