1. Ch. 20.2 Population Ecology pp.383-387
Growth rate =
birth rate – death rate
ADD:
Immigration = individuals move into the pop.
Birth rate = 𝑏𝑖𝑟𝑡ℎ𝑠 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒
SUBTRACT:
Emigration = individuals move out of pop.
Death rate = 𝑑𝑒𝑎𝑡ℎ𝑠 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒

2. Ch. 20.2 Population Ecology pp.383-387
Exponential growth = population is growing without limits
Common for bacteria, and in early growth
Sometimes called “doubling”
Cannot continue forever because soon goes to infinity
Resources always become limited

3. Ch. 20.2 Population Ecology pp.383-387
Limiting factor = a resource that runs out and limits growth
Food, habitat,…
Logistic growth = when a population grows to a maximum that the environment can support
Often starts exponentially but eventually reaches the limit

4. Ch. 20.2 Population Ecology pp.383-387
Carrying capacity = number of individuals (capacity) that the environment can carry for a long period of time
Abbreviated K
Birth rate = death rate; or balanced
How many days are the Paramecia below in exponential growth?
The daphnia…?

5. Ch. 20.2 Population Ecology pp.383-387
Density- independent limiting factors = limit growth but NOT related to population density
Weather, fire, pollution…
The limiting factor is independent of the size of the population

6. Ch. 20.2 Population Ecology pp.383-387
density-dependent limiting factor = does depend on the size of the population in the area
Food, nesting sites, finding mates, diseases
Inbreeding = loss of genetic diversity because of few individuals
Close relatives mating
Increase in genetic disease

7. Ch. 20.2 Population Ecology pp.383-387
flux = populations fluctuate, or constantly increase or decrease
Common in predator- prey interactions
Lynx and Snowshoe hare