POPULATIONS

Ecology Recap: Species, community, populations Food Webs and Food Chains Energy flow Trophic levels Producers, primary consumers, secondary consumers, tertiary consumers Autotrophs and heterotrophs Energy Pyramids Organism Relationships Competition Predation Symbiosis (mutualism, commensalism, parasitism) What is the difference between a community and a populations?

Population or Community? Vs. Individuals of same species Live in same area Many different populations that live together in the same defined area.

Why would this food web not be possible? Different habitats

Habitats: where an organism lives

Niche: an organism’s role in society Its place in the food web Range of temperatures that an organism needs to survive Its food What eats it

Habitat vs. Niche Species in the same habitat CAN’T have the same niche. Organisms = siblings/ twins Habitat = house Niche = chore of taking out the trash *both organisms (siblings/ twins) will not be able to do the same chore (niche) if they want to work in the same house.

Why can’t they occupy the same niche? Would be in competition and one species would lose out

But different species CAN live in the same habitat So they will interact Competition Predation Symbiosis Mutualism Commensalism Parasitism

Population Notes

How would you describe this population? image If you were a researcher studying populations what factors would you look at in this map? What do the colors show you? Location of the colors? Growing or decreasing?

Terms to Describe Populations: Range (distribution): a geographic range that is inhabited by a population Density: number of individuals in an area Growth rate: how fast or slow a population is growing Age structure: number of individuals in different age groups

Is a Population Growing or Decreasing? Factors that Determine Population Growth Rate Factors to look at.... Birth Rate Death Rate Immigration: Number that enter area Emigration: Number that leave area If you are looking at a growing population would it have more births or deaths?

Examples: Low death rate High birth rate High death rate Low birth rate Many people leaving the area

Example: Penguin Population At the beginning of the year 100 penguins During the year 50 were born and 20 penguins died and 15 penguins moved away to another population. Did the population grow or decrease?

Exponential Growth Exponential growth: when the individuals in a population reproduce at a constant rate A J- shaped Curve Happens when conditions are ideal

Logistical Growth Logistical Growth: Starts out like an exponential curve, but as the population increases, resources become limited, and growth slows. A S shaped curve Happens when resources are limited Carrying capacity: the number of individuals that a given environment can support

Limiting Growth Limiting factors Resources Predation Parasites and disease

Human Populations How has the size of the human population changed over time? Why do population growth rates differ in countries throughout the world?

Demography Demography: looks at the characteristics of human populations and attempts to explain how populations will change over time Researchers look at Birth rates Death rates Age structure of the population

Demographic Transition Slowing of the population growth

Analyze a Population Look at birth and death rates, but you also need to know... age structure

Age-Structure Diagrams

Societal Impacts? http://www.youtube.com/watch?v=R55e- uHQna0&feature=player_embedded http://www.youtube.com/watch?v=jV_u9EDE2Z8 http://www.youtube.com/watch?v=7OIEFo2axGE http://www.youtube.com/watch?v=ZmBDeswu2dI Passat vehicle