measuring and modeling population change

populations are

• dynamic and changing

• always in flux

• carrying capacity can change

biotic potential

Maximum reproductive rate under ideal conditions, no limit factors

carrying capacity (K)

number of individuals the environmental resources can support over a long period of time

exponential growth model

• organisms reproduce continuously at a constant rate

• not realistic

• doesnt including limiting factors

instantaneous growth rate

• change in the rate at a particular instant

• like a snapshot of population

doubling time

the amount of time required for population to double in size

logistic growth model

• describes limited population growth

• often due to limited resources or predation

logistic growth model phases

• lag phase: rate accelerates

• log phase: rate slows down

• stationary phase: once carrying capacity is reached

Exponential Vs. Logistic Growth

• exponential: unrestricted; growth rate of population accelerates

• logistic: restricted; realistic phases

does a decrease in rate mean less offspring produced?

life strategies

• species patterns of growth, survival and reproduction

• used in order to grow their populations or

• to make trade-offs to maximize the number of offspring that survive

r-selected life strategies

• spawners

• exponential growth

• temporarily large populations, followed by sudden crashes in population size

• short life span

• sexually mature at young age, many offspring

• Ex. Insects, bacteria, annual plants, algae

k-strategists

• brooders

• long life span

• sexually mature later in life

• produce few offspring and provide care

• generally live close to carrying capacity, logistic curve

• Ex. Mammals and birds