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 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.

Day 1 $0.01 Day 16 $327.68

Day 2 $0.02 Day 17 $655.36

Day 3 $0.04 Day 18 $1310.72

Day 4 $0.08 Day 19 $2621.44

Day 5 $0.16 Day 20 $5242.88

Day 6 $0.32 Day 21 $10,485.76

Day 7 $0.64 Day 22 $20,971.52

Day 8 $1.28 Day 23 $41,943.04

Day 9 $2.56 Day 24 $83,886.08

Day 10 $5.12 Day 25 $167,772.16

Day 11 $10.24 Day 26 $335,544.32

Day 12 $20.48 Day 27 $671,088.64

Day 13 $40.96 Day 28 $1,342,177.20

Day 14 $81.92 Day 29 $2,684,354.40

Day 15 $163.84 Day 30 $5,368,708.80

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.

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

• Competition for drinking water• dependent

• Spreading of a disease• dependent

Reproductive Strategiesr-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•Exponential growth curve

•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)

RankCity / Urban

areaCountry Population

Land area(in km2)

Population Density/km2

1 Tokyo/Yokohama

Japan 33,200,000 6,9934750

2 New York Metro

USA 17,800,000 8,6832050

3 Sao Paulo Brazil 17,700,000 1,968 9000

4 Seoul/Incheon

South Korea 17,500,000 1,04916,700

5 Mexico City Mexico 17,400,000 2,072 8400

6 Osaka/Kobe/Kyoto

Japan 16,425,000 2,5646400

7 Manila Philippines 14,750,000 1,399 10,550

8 Mumbai India 14,350,000 484 29,650

9 Delhi India 14,300,000 1,295 11,050

10 Jakarta Indonesia 14,250,000 1,360 10,500

64 Atlanta USA 3,500,000 5,083 700

http://www.citymayors.com/statistics/largest-cities-population-125.html

Growth curve for the human population

http://www-popexpo.ined.fr/eMain.html

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.

• "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."