all the members of one species in a particular area
DESCRIPTION
Population A Population B Both areas have a population of 9.TRANSCRIPT
Studying Populations
PopulationAll the members of one
species in a particular area
What is the population?
Population A Population B
Both areas have a
population of 9.
Population densityThe number of individuals
in an area of a specific size.
What is the population density?Area A Area B
Population A has a population density of 9/ yard2.
Population B has a population of 9/ foot2.
The areas have the same population but different
population densities.
One yard2
One foot2
Population ◦tells how many organisms there are◦is written as a number 328 burch trees 250,000 people
Population Density ◦Tells how many organisms are in a certain◦is written as a number over an area◦shows how dense, or “smushed together”, the
organisms are. 18 burch trees/ acre 2 people/ meter2
Population vs. Population Density
Direct ObservationCounting all the members
of the population.
Indirect ObservationCounting signs of an organism instead of counting the actual
organism.
SamplingCounting the organism in a
small area and then multiplying to find the larger area.
Mark-and-RecaptureScientists capture animals and mark them.
They go back later and recapture the animals.
Scientists see how many are unmarked and then apply a formula to estimate the total
population.
Limiting factorAn environmental factor
that prevents a population from increasing.
Carrying CapacityThe largest population that
an area can support.
Ecology Terms
An organism’s job or role in the ecosystem.
Includes: what an organism eats, how it obtains food, and
any predators.
Niche
The specific environment that provides the things an organism needs to live, grow, and reproduce; an organism’s
home.A habitat provides food, water, shelter,
living space.
Examples: For fungus=moist earth of the forest floor.For an earthworm=tunnels in garden soil.
Habitat
All the organisms of the same species living in the same
area at the same time.
Examples:All the prairie dogs in a prairie.
All the red oaks of a forest.
Population
All the different populations living in the same area at the
same time.
Example:All the living things (bacteria, protists, fungus, plants, and
animals) in a forest.
Community
A community of living things in an area and their nonliving
environment.
All the living things in a forest, plus the soil, rocks, water, air
temperature, and weather.
Ecosystem
An environmental factor that prevents a population from increasing.
Examples:FoodWaterShelter
Living spaceWeather conditions
Number of predatorsNumber of competitors
Limiting Factor
The largest population that an area can support.
Limiting factors often determine the carrying capacity of an area.
Populations usually stay around the carrying capacity.
Carrying Capacity
The struggle between organisms to survive as they
attempt to use the same limited resources.
Two or more predators that feed on the same prey.
Snakes and hawks compete for mice.
Competition
Often animals can live in the same area and not compete, because they have different
niches. They may eat different foods.
Note:
A relationship between two organisms in which one
organism kills another for food. Also called predation.
Examples:A coyote and a rabbit
A bird and blueberry bush
Predator-Prey Relationship
A close, ongoing relationship between two organisms of
different species that benefits at least one of the organisms.
Note: Predation is not symbiotic, because predator-prey
relationships are quick, not ongoing.
Symbiosis
A symbiotic relationship between two organisms in
which both organisms benefit.
Example:A sea anemone and a clown
fish.
Mutualism
A symbiotic relationship between two organisms in
which one organism benefits and the other organism is
neither helped nor harmed.Example:
A bird builds a nest in a tree.
Commensalism
A symbiotic relationship between two organisms in
which one organism benefits and the other organism is
harmed.
Example:Fleas on a dog
Parasitism
The organism that a parasite (or virus) lives on or in and is harmed in a parasitic relationship.
Host
Parasite The organism that benefits by living on or in
a host in a parasitic relationship.
A behavior or physical characteristic that allows an organism to survive in its environment.
Adaptation