What causes populations to change?

A population is a group of

individuals of the same species that

live in the same geographic area
that interbreed with each other.

Populations need specific

things. Anything that
restricts a population's

size and slows or stops it
from growing is called a

limiting factor.

Limiting factors

Biotic Limiting Factors are
living or once-living things that
affect population sizes

Example: food sources

Abiotic Limiting Factors are
nonliving things that affect
population sizes

Example: a wildfire

Limiting Factors Practice

Sort the limiting factors in your notebook

either biotic or abiotic.

Correct Answers

Factors that affect
population growth

How do these affect a population?

●Natality: individuals born

●Mortality: individuals died

●Immigration: individuals
coming in

●Emigration: individuals
leaving

Factors that affect
population growth

INCREASES POPULATION

●Natality: individuals born

●Immigration: individuals
coming in

DECREASES POPULATION

●Mortality: individuals died

●Emigration: individuals
leaving

Carrying Capacity is

the maximum

population size that

can be supported
sustainably in an

area.

Example: A population of fish is “stable” and at
carrying capacity when they grow, thrive, and
reproduce without fiercely competing for food,
water, space and a mate

Notice:

The

population is

stable at
carrying
capacity.

Logistic and Exponential Growth Curve

Exit Ticket

In your notebook...

What is happening to
the human population?
Why?

Can the world continue
at this growth rate?
Explain why or why not.