Aim: How do different types of populations grow?

DO NOW1. Which organism is

the predator in this graph? Which is the prey?

2. What happens to the population of moose in ~1982?

Carrying Capacity

• The number of organisms of a species that can live & survive in an area

• Dependent on the amount of resources in an area & the work of decomposers

• Limiting factors affect carrying capacity, either increasing or decreasing carrying capacity!

• Limiting factors can include the amount of food & water available, how many predators exist in the area & if disease is present …etc.

Population Growth Graphs

• Dashed line on a growth graph represents the carrying capacity

• J-shaped curve graph illustrates exponential growth of a population

• S-shaped curve graph illustrates logistic growth of a population

Exponential Growth

• Population grows slow at first, then grows fast, quickly!

• No limiting factors at work in the population’s environment no limits on growth or unrestricted growth

• Ideal circumstances no carrying capacity

Logistic Growth

• Population grows slow at first, then grows quickly, then growth slows or stops around carrying capacity

• Many populations grow like this• Limiting factors are at work! restricted growth

Exponential vs. Logistic Growth

Human Population GrowthHow is the human population growing with time?

What kind of growth is this population of fish showing?

Fluctuation of Growth around Carrying Capacity

• Population growth tends to fluctuate or go up and down, around carrying capacity, since limiting factors are at work! This is the stable equilibrium phase of growth!

Population Growth that has Stopped ! (at carrying capacity)

Video

• https://www.brainpop.com/science/ourfragileenvironment/populationgrowth/

Homework

• On page 109 in your textbook, write out & answer questions 4 & 5.

• In addition, on page 112, write out & answer questions 2, 6 and 7.

• Total # of questions to answer = 5 questions!• Good Luck!