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Ecosystems For Kids Made Easy!

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A fun science lesson and video on different types of ecosystems for kids in 3rd, 4th and 5th grade!

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An ecosystem is a community of interacting organisms and their environment. Living things interact with each other and also with non-living things like soil, water and air. Ecosystems often contain many living things and can be as small as your backyard or as large as the ocean.

To learn how the different types of ecosystems work…


An ecosystem is a community of interacting organisms and their environment.

zebras in a Savannah ecosystem

Many people only think of animals when they learn of ecosystems, but in reality, an ecosystem has animals, plants, and NON-living things too. Animals need to hide inside rocks and dead trees. Water is needed to drink and some animals live in the water. Air is a non-living part of an eocsystem as well — all animals need air.

Some ecosystems provide special services for the entire world. For example, even though rainforests only cover 6% of Earth, they produce about 40% of the oxygen in the atmosphere through photosynthesis. Other ecosystems produce food, medicine, and helpful materials like rubber and lumber.

Organisms only survive in an ecosystem when their specific needs are met.

closeup of a cricket eating a leaf

All organisms have needs, such as food, water, and air. If the needs of the organisms in the ecosystem are not met, they cannot survive.

Animals usually need food, water, and shelter. For example: if deer need to eat grass and the place they live in (their ecosystem) no longer has grass, they have to move somewhere else or risk not surviving.

A healthy ecosystem has many different kinds of organisms.

bird nest in a backyard ecosystem

When you think of an ecosystem, such as a forest, there are many organisms that are important. Trees, deer, plants, birds, squirrels, and insects are prominent members of the ecosystem. There are many more organisms that live in an ecosystem that are not as noticeable.

We often forget about all the bacteria, fungus, and tiny insects that are equally important. Ecosystems depend on many organisms to keep them in balance.

When that balance is disrupted organisms cannot thrive, and some may even die. Possible disruptions caused by humans include pollution, deforestation, land development, or removing too many resources like water. Making wise choices to protect ecosystems will help all the living things continue to live and thrive. It’s important to remember that not all disruptions are caused by humans, some happen naturally.

Newly introduced organisms can throw off the balance of an ecosystem.

feral pigs eating grass which are an invasive species

Another way humans impact ecosystems is by introducing invasive species. Invasive species are living things not naturally found in that ecosystem.

They upset the natural balance. Wild pigs were introduced to the United States centuries ago. Each year they cause billions of dollars of damage to crops. Wild pigs eat turkey eggs and other animals. Since they are no longer in their native environment, wild pigs do not have any natural predators, so their population is difficult to control.

In nature, an ecosystem is balanced with predator-prey relationships that keep populations from getting too high.

When invasive species are introduced three possible things can happen to existing animals. (1) The animals can adapt and stay in that ecosystem. (2) The existing animals die or (3) the animals can move somewhere else to find a new home.


pond ecosystem with frogs, bugs and grass

A small puddle can be its own ecosystem. All the organisms needed to have a well-balanced ecosystem can exist on a small scale.

spraying too much fertilizer can damage an ecosystem

Using too much fertilizer can damage ecosystems. In some cases, pesticides kill a lot more bugs than they are intended to. This means less bugs to eat for some animals. It causes a disruption in the balance of the whole ecosystem.

ecosphere containing shrimp and plants

Ecospheres are ecosystems you can have on your desk. These mini ecosystems are completely balanced and only require a source of sunlight. They contain algae and shrimp which make food for each other.


A community of interacting organisms and their environment. Living things interact with each other, and also with non-living things like soil, water and air.
A scientist that studies plants.
A sweet, sugary liquid made inside flowers. Insects and hummingbirds feed on.
An area densely packed with lots of different kinds of plants, tall trees and animals. Rainforests get a lot of rain (about 100 inches of rain per year). All that rain allows lots of different plants to grow and lots of animals live near those plants. Rainforests also produce a lot of oxygen that humans breathe and scientists estimate that there are millions of different kinds of living things still undiscovered in rainforests.
Invasive species
Living things not naturally found in that ecosystem. They usually cause damage or throw off the balance of the natural ecosystem.
Living Things
Anything living such as an animal, plant, insect, bacteria, etc.
Anything that doesn’t grow and reproduce such as rocks, soil, air or water.
A living thing similar to a plant that is usually found growing in water. They produce their own food through photosynthesis like plants do, but algae have no leaves, stems or roots.
A closed container of plants and other living things that shows you how an ecosystem works.
Tiny living things that are everywhere around us. We can only see them with a very powerful microscope. They come in different shapes such as rods, spirals, and spheres. Bacteria are important in an ecosystem to break down dead and decaying matter.


How big is an ecosystem?

Ecosystems range from the size of your backyard to an entire ocean.

How do the components of Dr. Jeff’s ecosphere interact to help each other survive?

In the enclosed ecosphere, the algae uses sunlight to grow. The algae is then eaten by the shrimp. The shrimp’s poop provides food for bacteria which convert the poop to nutrients that help the algae to grow. It’s a cycle!

Why would the shrimp in the ecosphere die if there was no sunlight?

The shrimp in the ecosphere depend on the algae for food. If there was no sunlight, the algae would die, which leaves no food for the shrimp.

What are some of the components of a rainforest ecosystem and how do they interact?

Rainforest ecosystems contain lots of plants. Plants provide food and homes for animals like birds and butterflies. Birds build nests in plants. Bugs eat leaves of plants and birds drink nectar from flowers. Some plants also make fruit which animals eat.

Why are rainforest ecosystems important?

Rainforests cover only about 6 percent of the planet but are responsible for producing about 40% of the oxygen we breathe!

What are some parts of a freshwater ecosystem?

There are many examples. Some of the examples in the video include fish, crabs, shrimp, turtles, algae, plants, dead wood and rocks. All these are part of a freshwater ecosystem.

What are examples of good and bad ways humans can impact a saltwater ecosystem?

Humans can positively impact a saltwater ecosystem by being careful not to over fish. Humans can negatively impact a saltwater ecosystem by allowing fertilizer from farms to flow into the ocean, which can lead to blooms of algae. Too much algae can kill fish.

How could animals and plants respond to seasonal changes in an ecosystem?

In the winter, many animals migrate (move somewhere else) or hibernate (sleep for a long time) to avoid the cold of winter. Also, some trees lose leaves to conserve resources in the winter. In the spring, plants bloom around the same time that insects emerge to help pollinate the plants.

What are some components of a garden ecosystem and how do they interact?

Flowers in a garden provide nectar for birds, bees and other insects. Birds and insects transfer pollen between plants, helping the plants reproduce and survive. Trees provide shelter and nesting areas for animals like squirrels. Even small puddles in gardens are ecosystems! They contain algae, worms and insects.
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