Living Things and the Environment: Organizing the Living World
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What does an Organism Get from Its Environment?
A living thing, or organism, needs certain things to live, grow and reproduce. An organism gets food,
water, shelter, and other things that it needs from its environment.
An environment that provides the things a specific organism needs to live, grow, and reproduce is
called its habitat. A prairie dog gets food, shelter, and other things from a prairie dog habitat that has
flat land, tall grasses, and little rainfall. A rocky ocean shore habitat would not provide what a prairie
dog needs to survive.
What are the Two Parts of an Organism’s Habitat?
Biotic factors are the living, once living, parts of a habitat. In the prairie dog’s habitat, plants that
provide food and decomposing plants are biotic factors. Ferrets and eagles that hunt the prairie dog
are also biotic factors. Worms and bacteria that live in the soil are biotic factors too.
Abiotic factors are the nonliving parts of the habitat. Water, sunlight, oxygen, temperature, and soil
are all abiotic factors in a prairie dog’s habitat.
How is an Ecosystem Organized?
A species is a group of organisms that can mate with each other and produce offspring that can also
mate and reproduce. The black-tailed prairie dogs of the Nebraska plains are all members of one
species. A population refers to all the members of one species living in a particular area. All of the
prairie dogs in a prairie dog town are a population.
All of the different populations that live together in an environment are a community. Communities
include only the living things in an environment. For example, a prairie includes prairie dogs, hawks,
grasses, snakes, and many other organisms. An ecosystem is made up of the community of organisms
that live together in a particular area as well as the non-living surroundings.
Question: List the four levels of an ecosystem from smallest to largest; give an example of each.
1.
2.
3.
4.
5.
6.
Organism: any single living thing; giraffe
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Biosphere: All the places where living things can live; air, water, underground, on land surfaces