Populations

Population or not? The monkeys in a rainforest

E. coli bacteria growing in a petri dish

Humans on Earth

The cats in my neighborhood.

The trees in a forest

Population A group of organisms of the same species that live within a given area Ostriches are nomadic, wandering in small groups. Aspen trees are quick to pioneer areas that have been disturbed by fire. BioEd OnlineBioEd Online

a) Dispersion Give an example of each type

Gannets nesting

Solitary tree sloth

School of fish

b)Population density (total population size per unit of area)

c) Growth Rate (Births + Immigrants) - (Deaths + Emigrants) Population Size

One bacterium divides in two in 20 minutes. This process continues for several days. Sketch the population growth graph.

Exponential growth curve (J shape)

Exponential growth is a rapid population increase due to an abundance of resources.

Logistic growth curve (S shape) is due to a population facing limited resources. Carrying capacity is the maximum number of individuals in a population that the environment can support

Ecological factors limit population growth Density-dependent limiting factors are affected by the number of individuals in a given area.

Competition for food, shelter Predation Parasitism and disease

Density-independent limiting factors limit a population’s growth regardless of the density Unusual weather Natural disasters Human activities

Density - dependent or density – independent factor? Tornado independent Food supply dependent Amount of rainfall independent Temperature independent Available drinking water dependent Spreading of a disease dependent

Reproductive Strategies r-strategists (rapid growth) K-strategists (near carrying capacity) Early reproduction Short life span High mortality Little parental care Large number of offspring Insects, amphibians, bony fish Reproduce late in life Long life span Low mortality High parental care Few offspring Humans, other large mammals, sharks Logistic growth curve

Survivorship curves

Choose type I, II, or III for Humans Fish Lizards Birds Insects Lions Squirrels Plants

Population Pyramids

Who are the circled people? What is significant about them?

Most Populated Cities (1/6/2007) Rank City / Urban area CountryPopulation Land area (in km 2 ) Population Density/km 2 1 Tokyo/Yoko hama Japan33,200,0006, New York Metro USA17,800,0008, Sao PauloBrazil17,700,0001, Seoul/Inche on South Korea17,500,0001,049 16,700 5Mexico CityMexico17,400,0002, Osaka/Kobe /Kyoto Japan16,425,0002, ManilaPhilippines14,750,0001,399 10,550 8MumbaiIndia14,350, ,650 9DelhiIndia14,300,0001,295 11,050 10JakartaIndonesia14,250,0001,360 10,500 64AtlantaUSA3,500,0005,

Growth curve for the human population

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Doubling Time The amount of time needed for a population to double Doubling time (in years) = 70 annual percent growth rate The world’s annual growth rate is about 1.75%. What is the current doubling time? 40 years

What is an ecological footprint? The demands a person places on the environment in terms of land, water, food, waste, fibers, etc. Go to andwww.myfootprint.org take the quiz. Bring in your results.

"It's up to us to make a global effort to limit population growth - or we can wait until the environment does it for us."

Sources cited