Earth Science

Life on Earth

Biological Communities

Study Tip
To remember the different between biotic and abiotic factors, know that the prefix “a” before a word means not. So if biotic factors are living, then abiotic factors must be non-living.

Population and Species

A population is the collection of all members of a species (a single type of organism that can interbreed and produce offspring) in a given place and time. A biological community consists of multiple populations in an area.

Study Tip
To remember the different between biotic and abiotic factors, know that the prefix “a” before a word means not. So if biotic factors are living, then abiotic factors must be non-living.

Ecosystems

Ecosystems are biological communities consisting of living organisms, or biotic factors, and their environment, or abiotic factors. Examples of biotic factors are living organisms such as bacteria, algae, fungi, plants, and animals. Abiotic factors can be physical or chemical features such as light, nutrients, water, oxygen, and carbon dioxide.

Habitat and Niche

A habitat is where an individual lives. Climate, food, water, and weather are all important factors in an organism’s habitat. A niche (pronounced neesh) is an organism’s position within its environment. For example, a lion is a carnivore at the top of the food chain.

Houses
A house is an example of a habitat for humans.
Concept Check
  • What are biotic and abiotic factors?
  • What is the difference between a species, population, community, and ecosystem
  • What is a niche?

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