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