Habitat: The Place That Supplies Everything an Organism Needs to Live
Definition
Habitat
A habitat is the specific place where an organism, population, species, or community lives. The word comes from the Latin habitare, meaning "to live."A
A habitat has two main elements.
Geographical location is the physical area an organism lives in.
Physical conditions are the abiotic factors there, such as temperature, light, soil type, and water availability.
A habitat includes all the biotic (living) and abiotic (non-living) factors that affect an organism there.
Habitats vary hugely in scale, from a whole tropical rainforest down to the underside of a single leaf.
Example
The habitat of Ranunculus glacialis is high-altitude mountainous regions in Europe.
The abiotic conditions there include winter snow cover, well-drained soils, and intense summer sunlight.
Who Lives in a Habitat: From a Single Organism up to the Whole Community
An organism is a single living individual, such as one polar bear on Arctic sea ice.
A population is all the organisms of one species living in the same area, such as the polar bears in one region.
A species is all the organisms that can interbreed, such as every polar bear worldwide.
A community is all the populations living together in a habitat, such as polar bears, seals, fish, and algae in the Arctic.
Each of these levels depends on its habitat for both resources and suitable abiotic conditions.
Tip
When you describe a habitat, name both its abiotic conditions and the type of ecosystem it sits within.
Components of a Habitat: Biotic and Abiotic Factors Working Together
Biotic factors
These are the living elements, such as plants, animals, fungi, and microorganisms.
They include interactions such as predation, competition, and mutualism.
Abiotic factors
These are the non-living elements, such as temperature, light, water, soil, and air.
They often set the habitat boundaries and decide which organisms can survive there.
Example
In a mangrove habitat, the biotic factors include crabs and fish.
The abiotic factors, such as high salt levels and waterlogged soils, shape which species can live there.
Different Habitats Differ Mainly in Their Abiotic Conditions
A desert has low rainfall, extreme temperatures, and sandy soil.
A tropical rainforest has high rainfall, warm temperatures, and dense vegetation.
Analogy
Think of a habitat as a house that supplies shelter, food, and a place to rest.
Just as people live in different kinds of houses, different species need different habitats to meet their needs.
Habitat vs Niche: The Address Versus the Job
A habitat is where an organism lives, its address.
A niche is the role that organism plays in its ecosystem, its job.
Common Mistake
Do not confuse habitat with niche.
The habitat is the physical location, while the niche is the organism's role in the ecosystem.
Why Habitats Matter and What Threatens Them
A range of habitats lets many species coexist, which supports biodiversity and ecosystem stability.
Habitats supply organisms with food, water, shelter, and breeding sites.
Several human pressures threaten habitats.
Deforestation removes forest habitats.
Urbanization converts natural landscapes into cities and roads.
Climate change alters temperatures and weather, making some habitats uninhabitable.
Example
Rising sea levels threaten mangrove ecosystems.
Warming temperatures shrink Arctic sea ice and endanger polar bears.
Habitat Conservation Raises Questions of Knowledge and Ethics
Theory of Knowledge
Human actions such as deforestation and urbanization alter habitats.
To what extent should ethical considerations guide our decisions about habitat conservation?
Active recall
What are the two main elements of a habitat?
How does a population differ from a community?
What is the difference between a habitat and a niche?
Name one human pressure that threatens habitats and how it does so.
