Characteristics of Populations Three important characteristics of a

Population Growth Three factors can affect population size: a. the number of births b.

Immigration, the movement of individuals into an area Emigration, the movement of individuals out

Under perfect conditions with unlimited resources, a population will grow exponentially. Exponential Growth Copyright

As resources become less available (no more space, food, water, etc. ), the growth

Are humans experiencing exponential or logistic growth? Do you think humans are close

In the context of populations, a limiting factor is a factor that causes

Density-Dependent Factors a. A limiting factor that depends on population size is called

Competition a. When populations become crowded, organisms compete for food, water space, sunlight

Competition can also occur: between members of same species (intraspecific) between members of

Predation a. Populations in nature are often controlled by predation. Or Predator –

Wolf and Moose Populations on Isle Royale Copyright Pearson Prentice Hall

Parasitism and Disease a. Parasites can limit the growth of a population. b.

Density-Independent Factors a. Density-independent limiting factors affect all populations in similar ways, regardless

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Characteristics of Populations Three important characteristics of a population are its: a. geographic distribution b. population density c. growth rate http: //www. youtube. com/watch? v=RBOsqm. BQBQk

Population Growth Three factors can affect population size: a. the number of births b. the number of deaths c. the number of individuals that enter or leave the population A population can grow when its birthrate is greater than its death rate.

Immigration, the movement of individuals into an area Emigration, the movement of individuals out of an area

Under perfect conditions with unlimited resources, a population will grow exponentially. Exponential Growth Copyright Pearson Prentice Hall

As resources become less available (no more space, food, water, etc. ), the growth of a population slows or stops. Called carrying capacity Copyright Pearson Prentice Hall

Are humans experiencing exponential or logistic growth? Do you think humans are close to the Earth’s carrying capacity? Why? Copyright Pearson Prentice Hall

In the context of populations, a limiting factor is a factor that causes population growth to decrease. Can be: Density-dependent Density-independent

Density-Dependent Factors a. A limiting factor that depends on population size is called a density-dependent limiting factor. Density-dependent limiting factors include: a. competition b. predation c. parasitism d. Disease e. Most impact with larger populations

Competition a. When populations become crowded, organisms compete for food, water space, sunlight and other essentials.

Competition can also occur: between members of same species (intraspecific) between members of different species (interspecific) Intraspecific Interspecific

Predation a. Populations in nature are often controlled by predation. Or Predator – Prey Relationship Copyright Pearson Prentice Hall

Wolf and Moose Populations on Isle Royale Copyright Pearson Prentice Hall

Parasitism and Disease a. Parasites can limit the growth of a population. b. http: //www. ted. com/talks/ed_yong_suicidal_wasps_zomb ie_roaches_and_other_tales_of_parasites

Density-Independent Factors a. Density-independent limiting factors affect all populations in similar ways, regardless of the population size. • • unusual weather natural disasters seasonal cycles certain human activities—such as damming rivers and clear-cutting forests