unit 3 - populations

k-selected species

• fewer offsrping

• longer lifespan

• parental care

• type I/II curve

r-selected species

• many offspring

• mature early

• shorter lifespan

• type III curve

survivorship curve

a line that displays the survival rates of a cohort in a population

carrying capacity

the maximum number of individuals that can be supported by an ecosystem

overshoot

when a population becomes larger than the environment's carrying capacity

dieback

a sudden decline in population due to overshoot

total fertility rate

an estimate of the average number of children that each woman in a population will bear throughout her childbearing years

replacement-level fertility rate

average number of children a couple must have to replace themselves (2.1)

infant mortality rate

percentage of children who die before their first birthday within a particular area or country.

cbr

The total number of live births in a year for every 1,000 people alive in the society.

cdr

The total number of deaths in a year for every 1000 people alive in the society.

density dependent factors

disease, competition, predation

density independent factors

temperature, natural disasters

doubling time

70/growth rate

pre-industrial stage

birth and death rates high, population grows slowly, infant mortality high

transitional stage

death rate lower, better health care, population grows fast

post-industrial stage

low birth and death rates

growth rate equation

(CBR-CDR)/10