Do Now

• Collect materials from the front of the room• Turn in Symbiosis worksheet (if you didn’t do

it yesterday)• Take your seat• Remember: QUIZ ON Friday• Start working on Ecological Relationships

Model 1

Objective

• analyze population growth graphs and explain how limiting factors affect carrying capacity.

By the end of class, students will be able to:

Populations• A population is all of the organisms of one

species inhabiting a particular place

Population Size• Populations can increase or decrease in size

depending on different factors.

Population Size

• What can cause a population to grow in size?

Population Size

• What can cause a population to grow in size?

Births Immigration

Population Size

• What can cause a population to decrease in size?

Population Size

• What can cause a population to decrease in size?

Deaths Emigration

Population Growth Models

• Exponential vs. Logistic Growth

Exponential Growth

• J curve• Unlimited

resources

Logistic Growth

• S Curve Limiting factors

Which Occurs More in Nature?

Which Occurs More in Nature?

• Logistic Growth!

• Why?

Exponential Growth

• J curve

• Why is the water overflowing in the picture below?

Capacity• The maximum amount something can hold

• How does this relate to logistic growth of populations?

Carrying Capacity• The population size an area can support

• Note: specific to the area and to the species!

What determines carrying capacity?

Limiting factors

• Density-dependent factors• Density-independent factors

Density Dependent

• Predation• Competition• Infectious

disease• Prey

availability

Density Independent

• Genetic diseases• Weather

Populations can exceed their carrying capacity … for a while

Please finish

• Questions 1-9, 11-13

Speaking of overpopulated

Exit Ticket

• Silently without notes!

• Why do populations have a carrying capacity?• (In other words why can’t populations

continue to grow forever?)