Biology Basics: Ecosystems

By Rene Fester Kratz from Biology Workbook For Dummies

Life thrives in every environment on Earth, and each of those environments is its own ecosystem, essentially a little machine made up of living and nonliving parts that interact with one another in a particular environment. An ecosystem can be very large, like the open ocean, or very small, like the ecosystem inside the digestive system of an ant. The living parts of an ecosystem, called biotic factors, are all the organisms that live in the area. The nonliving parts, called abiotic factors, are the nonliving things in the area.

All the living things together in an ecosystem form a community. Within a community, each group of the same kind of organism that lives in the same area at the same time is a population. This figure shows how these levels of organization intersect with one another and with other levels of biological organization.

The organization of living things.

Try these questions to see how well you understand basic ecosystem terminology.

For questions 1–3, use the terms that follow to identify which level of biological organization is represented by each scenario.

a. Ecosystem

b. Community

c. Population

Your friend is a beekeeper and has a hive of bees in his backyard. What does the group of bees living in the hive represent?
You go to the beach on a sunny day and walk on the rocks at the edge of the ocean. You see mussels and algae growing on the rocks, and you find small crabs, anemones, and fish in some tide pools. What does this rocky area represent?
In a forest, trees are often inhabited by birds, squirrels, insects, and fungi. What do the living things in the tree represent?
Imagine your backyard or a natural area near your home. Identify the abiotic and biotic factors that exist in this ecosystem.

The following are answers to the practice questions presented.

The answer is c. Population.
The answer is a. Ecosystem.

The rocky intertidal zone contains interconnected biotic and abiotic factors.
The answer is b. Community.
Your answer depends on the environment you chose, but in general, abiotic factors include sun, rocks, air, and water.

Biotic factors include all organisms such as plants, insects, birds, and mammals. Materials such as soil or a pond, which contain both living and nonliving components, can be hard to classify. In those cases, identify what parts are living or nonliving. For example, the minerals that make up soil are abiotic, while the bacteria and fungi that live in soil are biotic.