POPULATIONS

A population . . . consists of all the individuals of one species that live together in one place at one time. A species can interbreed and produce VIABLE offspring.

Population Density: The number of individuals of a species that live in a given area.

Carrying Capacity: Usually represented on graph as horizontal line: The number in a population that an area can sustain. Usually represented on graph as horizontal line:

Exponential Growth Curve: Uncontrolled growth – leads to a crash. Carrying Capacity Population Size Time

Exponential Growth Curve: Uncontrolled growth – leads to a crash. Carrying Capacity Population Size Time

Logistic Growth Curve: Controlled population growth. Population Size Time Carrying Capacity

A population . . . may increase slowly or decrease as their size is limited by density-dependent factors.

Density-dependent factors: Factors that limit the population due to the size of the population. Examples: population stops growing due to predation, disease, starvation, competition

A population . . . may increase slowly or decrease in response to density-independent factors.

Density-independent factors: Factors that limit the population but have nothing to do with the population. Examples: population stops growing due to flood, pollution, weather, climate

Adaptations: Changes made in traits allowing a species to survive natural selection in changing environments Examples: bird’s changing feather color to survive and attract mate, mouth parts changing to survive on different food items

Which graph shows overpopulation of a species no matter what factors are present? time Pop # A B Pop # time C Pop # D Pop # time time

D Pop # time A decrease on a population growth curve shows the population overpopulated the area no matter what resources or limiting factors where there. The cause of the decline was overpopulation.

Which of the following contain “environmental factors”? Organisms Populations Communities Ecosystems

“Environmental factors” can be abiotic! Ecosystems “Environmental factors” can be abiotic!

Which of the following explains the graph below at point “A”, “B”, “C”? time Pop # predator prey C B A When predator increases, prey decreases When prey decreases, predators decrease When predators decrease, prey increase

“A” When predator increases, prey decreases “B” When prey decreases, predators decrease “C” When predators decrease, prey increase time Pop # predator prey C B A