Bright blue marble spinning in space

Population Ecology

Population Ecology

population

ecosystemcommunity

biosphere

organism

Life takes place in populations Population

group of individuals of same species in same area at same time

rely on same resources

interact interbreed

Population Ecology: What factors affect a population?

Population Size Changes to population

size adding & removing

individuals from a population Birth and Death Immigration and

Emigration B+I – D+E = growth (+ or -)

African elephantprotected from hunting

Whooping cranecoming back from near extinction

Exponential growth rate – J Shape Curve Characteristic of populations without

limiting factors

Regulation of population size Limiting factors

food supply, competition predators disease abiotic factors

sunlight temperature rainfall

K =Carryingcapacity

Logistic rate of growth Can populations continue to grow

exponentially? Of course not!

effect of natural controls

no natural controls

Maximum population size that environment can support with no breakdownof habitat varies with

changes in resources

Time (years)1915 1925 1935 1945

10

8

6

4

2

0

Num

ber o

f bre

edin

g m

ale

fur s

eals

(tho

usan

ds)

Carrying capacity

Human population growthWhat factors have contributed to this exponential growth pattern?

1650500 million

20056 billion

Industrial Revolution

Significant advancesin medicine throughscience and technology

Bubonic plague "Black Death"

Is the human population reachingcarrying capacity?

Population of… China: 1.3 billionIndia: 1.1 billion

adding 82 million/year

AnyQuestions?