Population Growth

Agenda 1.CH 5-1 Population Growth 2.CH 5-2 Limits to Growth

Population A population has 4 characteristics –Geographic distribution –Density –Growth rate So how many students are in here? How about in two rooms? Population density –the number of individuals per unit area

Volunteers How can a population change?

Populations can change by: Immigration – moving into a population Emigration – moving out of a population Birthrate Deathrate

Population growth graph X axis = time Y axis = number of individuals Exponential Growth (J curve) –Ideal conditions with unlimited resources –Population grows exponentially Logistic growth (S curve) –Resources are less available –Population growth slows or stops

Number of Mice Time (hours) Carrying capacity

Population Growth can be represented bycharacterized by represented by which cause a Exponential growth Logistic growth Falling growth rate S-shaped curve Limits on growth No limits on growth J-shaped curve Constant growth rate Unlimited resources Concept Map

Limiting Factors ► Limiting factor  A situation that causes the growth of a population to decrease 1. Some limiting factors depend on the size of the population. 2. Other limiting factors affect all populations in similar ways.

Limiting factors 1. Density dependent factors  Affected by population  Food, space, competition, waste, so on 2. Density independent factors  Population does not affect it  Natural disasters, weather ► Both are limiting factors that affect the overall population

Wolf and Moose Populations on Isle Royale MooseWolves

Homework SA 5-1 #1-6 SA 5-2 #1-5 Read Ch 5-3