population density
number of organisms per unit area (how crowded something is)
Distribution
how things are dispersed
Dispersion
arrangement of population in their environment
what are the three kinds of dispersion?
uniform, clumped, random
Uniform
the same, consistently found
Examples of uniform dispersion
Bears, bobcats, tigers, territorial animals
Examples of clumped dispersion
school of fish, ants, herds of bison, flocks of geese
Examples of random dispersion
Spiders, squirrels, rabbits, deer
Examples of uniform and clumped dispersion
pride of lions, pack of hyenas
population ranges
where it lives–is the range of tolerance
population limiting factors
factors that limit where an organism can live
how many types of limiting factors are there?
2 types
what are the two types of limiting factors?
density-independent factors and density-dependent factors
Density-independent factors
do not depend on population (abiotic factors)
Density-dependent factors
Density-dependent factors- do depend on population (biotic factors)
examples of density-independent factors
any kind of weather…precipitation, wind, temp, humidity
examples of density-dependent factors
disease, competition, parasites, etc.
Population Growth Rate (PGR)
How fast a population grows/reduces
What are the four factors in PGR?
Natality, mortality, immigration, emigration
Natality
birth rate in a time period
mortality
death rate
immigration
into a population
emigration
exiting a population
Lag Phase
no to very little growth over a long period of time
Exponential growth
growth rate is proportional to to the size of the population
when exponential growth is happening, what does the species NOT have to worry about?
limiting factors
Logistic Growth Model
the growth rate slows when reaching carrying capacity
Carrying capacity
size of the population and limiting factors/resources determine carrying capacity
reproductive patterns
Different species have different reproductive patterns
R-strategists
Generally smaller organisms
Short life span
Produces many offspring
Low survival rate
K-strategists
Generally larger organisms
Long life span
Produces few offspring
High survival rate
examples of R-strategists
flies, some insects, sea turtles, some fish, most plants
examples of K-strategists
whales, elephants, mice, most birds, etc.