honors biology chapter 2.1 – 2.7 population ecology

Honors BiologyChapter 2.1 – 2.7

Population Ecology

IndividualOne organismEx: Canis lupus, 1 Wolf

PopulationA group of one species living in an areaEx: 1000 foxes in Kendall Co.

Population DensityThe number of individuals per unit areaEx: 6 wolves/km2

What is the density of house sparrows?

1 square km

What is the density of white-tailed deer?

1 square km

The pattern of spacing among individualsClumped, Uniform, Random

Population Dispersion

Population GrowthPositive Population Change

Natality: birth rateImmigration: entering

Negative Population ChangeMortality: death rateEmigration: leaving

Exponential GrowthUnder ideal conditions with unlimited

resources, the larger a population gets, the faster it grows.

Logistic GrowthEventually populations run out of space

and resources

Carrying CapacityThe maximum number of individuals the

environment can support

Population Size LimitationsDensity Dependent Factors

Limitations of a population due to the size of the population

Density Independent FactorsLimitations of a population with no

relationship to the size of the population

Density Dependent FactorsCompetition

Food, water, shelter, spacePredationDisease

Parasites, illness

Density Independent FactorsNatural Disasters

Tornado, Hurricane, Volcanism, etc.TemperatureHuman Activities

Honors BiologyChapter 2.8 - 2.12

Human Population Problem

7000 BCEworld population: ~7 million people

4000 BCEworld population: ~20 million people

1000 BCEworld population: ~50 million

1800 CEworld population: ~ 900 million

Human Population History

Human Population History

Human Population History

If exponential growth continues… In 573 years… 1 person/m2 on Earth In 1546 years… mass of humanity = mass

of the earth No exponential growth can continue

indefinitely

Planet Earth’s carrying capacity~10 billion peopleThis might be reached by 2050

Estimated Human Pop. Growth

Limiting Factors of Human Pop.Food, Water, ShelterAll come from the environment

Easter Island MysteryRemote, 163km2 island ~2,000mi off coast

of ChileA group of people arrived by boats around

1100CE By 1600’s, population rose to ~15,000

people

Easter Island MysteryIn 1722, Spanish arrived and only 2,000

people remained21 species of trees & 30 species of birds

extinctFell to only 111 people in 1877

Diseases from Europeans