Chapter 43: Populations Flashcards
population
individuals in a species that interact with one another within a given area at a particular time
Population density
a measure of abundance
number of individuals per unit of area or volume
usually first measure of abundance taken
population size
total number of individuals in a population
a measure of abundance
counting only practical for teeny populations
Geographic range
the region where species are found
Habitats
the particular kinds of environments where species can live
habitat patches
islands of suitable habitat separated by unsuitable habitat
BD model
N sub t + 1 = N sub t + B - D
n is population b is births from t to t+ 1, d = deaths in that time
growth rate
rate of change of a population
cohort
sample of individuals that scientists can keep track of over time
per capita birth rate
the number of offspring that the average individual produces
per capita death rate
the average individual’s chance of dying
per capita growth rate
b-d
where b is the per capita birth rate and d is the per capita death rate
represented by r
life history
the time course of growth and development, reproduction, and death during an average individual’s life
life table
quantitative summary/ description of the life cycle and life sycle transitions of a species
survivorship
the fraction of individuals who survive from birth to different stages
fecundity
the average number of offspring an individual produces at each age/stage if they do survive
Life expectancy
the age to which an average person survives
Resources
material, energy, and the time available to acquire them
can be used up
Physical conditions
organisms need physical conditions that they can tolerate
not consumed
principle of allocation
once an organism has acquired a unit of a resource, it can be used only for one function at a time
first priority is to maintain homeostasis
life-history tradeoffs
negative relationships among growth, reproduction, and survival
invest in growth early, cant invest in defense
invest in reproduction at the expense of longevity
Multipilicative growth
populations exhibit this
grow by constant multiples
Additive growth
grow by constant numbers
Doubling time
constant in multiplicative growth when the population added equals exactly the inital population
