Freshwater ecosystems are relatively small and account for less than 0.5 percent of Earth's water, according to National Geographic. Show children pictures of lakes, ponds, rivers and streams, and discuss the various life forms found in this ecosystem. Some examples are freshwater fish, frogs and some birds. Have children choose a favorite freshwater animal and create a mask that looks like it. Supply paper plates and other craft material for children to use to make the masks. Have the children stand together, and take a picture of children wearing their masks. Reproduce the picture, so children can give it to their parents as a souvenir of the lesson.
There are many terrestrial ecosystems, and they are diverse in style. There are seven major types, classified as tropical rain forest, savanna, desert, temperate grassland, deciduous forest, coniferous forest and tundra. Create a bulletin board with photos of each of the terrestrial ecosystems along with a brief description of each. Have children use shoe boxes to make dioramas. Let them choose their favorite ecosystem to feature. For instance, a child could choose to feature a tropical rain forest in a diorama. The shoe box could be painted green and could feature silk plants and vines with pictures of tropical animals.
The ocean ecosystem is very large. About 75 percent of Earth is covered by ocean, and about 40 percent of all photosynthesis occurs in these oceans. Teach children that the ocean ecosystem is divided into three types of smaller ecosystems: shallow ocean waters, deep ocean water and deep ocean surface. Divide the class into three groups, and assign one ocean ecosystem to each group to research. Ask the children to make puppets out of paper bags to represent some of the ocean life found in their ecosystem. Then have the groups use their puppets as they make a short presentation in front of their classmates about their ecosystem .
Help children create a class book about Earth's ecosystems. Teach children about the various ecosystems of Earth, and then ask them to choose their favorite to learn more about. Have each child create a scrapbook style page about the ecosystem of her choice. Once all the pages have been done, compile them into a class book for the classroom library.
Other lesson plans include reading books about ecosystems such as "Life in the Rainforests" by Lucy Baker or "My River" by Shari Halpern. Have children draw their own pictures based on the books.