Do Now Get out your notebooks On page 9, prepare to do our first 15 for the day We will begin our questions when the bell rings! I will be taking volunteers to be our officers for the day! Remember: President: Stamps First 15 Vice President: Takes attendance & collects works for absent students Secretary: Hands out materials

The tertiary consumers in an energy pyramid contain 6,400 kilo calories of energy. Predict how much the producers have. .640 kcal 64 kcal 64,000 kcal 6,400,000 kcal

How Many Bears Analysis Questions What percent of the bears survived? What is the class total of pounds of food eaten? Divide the total by the 50 pounds needed by an individual bear (approximately in order to survive in a 10 day period. How many bears could the habitat support? Why then did only ___ bears survive when the class did this activity? Is that realistic? What percentage would have survived had the food been evenly divided? Other than food, what factors, natural or human-related, might also limit the growth of the bear population? What was the theoretical carrying capacity of this activity? What was the true carrying capacity? Could the bear population increase indefinitely if unlimited food were available? Why or why not?

What can you infer from this graph?

POPULATION DYNAMICS UNIT 2: ECOLOGY

Population Characteristics A group of the same species makes up a population Populations are characterized by Density- how many in a given area Spatial distribution- how they are dispersed Population Range- where animals are found Growth rate- how fast population grows

Population Density # of organisms per given unit of area. May depend on what that animals population range is Ex: bears need several hundred kilometers of space to prevent competition so their populations would not be as dense as another’s.

Spatial distribution- Dispersion Pattern of spacing of a population in an area Can be: Random- unpredictable spacing Deer in forest Uniform- evenly dispersed Bears need certain sized territory Clumped- many together Cattle egrets congregating near cattle

Population range Where animals are found Depends on abiotic and biotic factors in that ecosystem Range of trumpeter swan- notice how it has changed… why do you think that has happened?

Can populations grow unchecked? Exponential Growth Population multiplies quickly Produces J-shaped curve Only occurs when there are enough resources for all to survive. Mostly unrealistic

How do populations grow realistically? Populations grow then level out due to limiting factors. Carrying Capacity- max. # of individuals an area can hold and still remain healthy. Produces S-shaped curve

What types of limiting factors limit population growth? Two types:

1. DENSITY-DEPENDENT Dependent on population size Produces s-shaped oscillation around carrying capacity Ex: food supply, predation, disease, living space, water availability, parasitism

2. DENSITY-INDEPENDENT Affects the same percentage of population regardless of population size. Shows a “boom & bust” curve EX: natural disasters, human disturbances, climate, change of seasons.

HUMAN POPULATION GROWTH Currently our growth is exponential. Exponential growth due to: Advances in technology Energy development Advances in agriculture Transportation Medicine We do not know our carrying capacity.