Ecology is the study of the interactions between living things and their environment. Organisms obtain their needed resources (food, water, light, etc.) from the environment. They react to changes in their environment as well as cause changes. Organisms can be producers, consumers, or decomposers. The roles organisms play is dependent on the ways they obtain energy and how they interact with other organisms.
The Earth's biomes
A biome is a habitat with similar climate and vegetation. The Earth is separated into terrestrial and aquatic biomes.
The terrestrial biomes include the tundra, taiga, deciduous forest, grassland, desert and tropical rainforest.
Tundra: The tundra has extremely cold temperatures. Because of this, there is a very short growing season. There are very few trees. Vegetation such as mosses and grasses grow here. Animals such as reindeer, caribou and wolves are found here.
Taiga: The taiga is also cold, but not as cold as the tundra so the growing season is longer. Pines, firs, and spruce grow here. Moose, wolves, bears, deer, birds, and insects live here.
Temperate Deciduous Forest: Here the summers are hot and the winters are cold. Some trees that grow here include oak, chestnut and birch. Animals that live in this biome include deer, squirrel, chipmunks, and birds.
Grasslands : The grasses are the dominant form of vegetation in this biome because of the small quantity of rainfall. In North America, the animals that live here include coyotes and rattlesnakes. In Africa, animals such as zebras and giraffes live here.
Deserts : This biome is so dry that grasses are unable to grow. Plants and animals in the desert have special adaptations that allow them to live in especially dry areas. Some animals that live in this area include snakes, lizards and spiders.
Tropical Rainforests: The temperature in this biome is constant and so is the rainfall. There are a wide variety of plants and animal species that live in this area.
The aquatic biomes are separated into two types: Marine and Freshwater.
Marine Biome (i.e., Saltwater Biome): This biome covers more than 70% of the Earth's surface. There are a great variety of plant and animal life living in the oceans.
Freshwater Biomes: Freshwater biomes are divided into two categories: running water (streams) and standing water (lakes, ponds, swamps, bogs). A variety of organisms live in this biome including algae, snails, and crayfish. Raccooms, birds, and other organisms live along the banks.
- Ask students to write answers to these questions in their science journal:
Why should my students ask and answer questions in science?
How can I help my students ask and answer questions in science?
Once students have written in their journals, facilitate a whole class discussion around the questions. It is important to allow students to answer freely - do not correct any misunderstandings at this time. The purpose of this discussion is to pique students' curiosity, provoke them to think about the topic, and obtain their prior understandings. Students should have an understanding of the characteristics of a desert if they did the Biomes lesson. Some students may know that plants and animals have adaptations that allow them to live in certain environments like the desert - but many will believe that these adaptations occurred over very short periods of time
Separate students into groups of three. Give each group a sponge saturated with water and a balance.
Explain to students that the sponge represents an animal living in the desert with a limited supply of water. It is each group's task to create an organism that is able to conserve as much water as possible. Students may use any of the supplies on the "supply table." (see above) Encourage students to be creative with their designs. It is important that the "organisms" (i.e. sponges) are exposed to air for several hours during the day.
Why should I use representations to teach science?
How should I use representations to teach science?
Before creating their "organism," have each group weigh their sponges and record it on a chart on the board.
Next, students should plan their strategies and write these down - What types of things are they going to use to help the sponge conserve as much water as possible? When complete, they should get their plans approved by the teacher. Encourage students to use their prior experiences with these materials to plan their strategy.
Have students carry out their "plan."
Have students weigh their sponges over the next several days. Record these on the board.
Why should students collect evidence to answer questions?
How can I help my students collect evidence?
When everything is completed, have students share their results with the class.
Pose the following questions to the class:
- How do plants and animals survive in the desert?
- Do you think we would survive in the desert? Why or why not?
- What would we need in order to survive?
How can I help students draw conclusions based on evidence?
Facilitate a class discussion around these questions. It is important for students to use evidence to back up their claims - which is often difficult for children to do. Be sure to ask "why" if they just state an answer. Most desert plants and animals have developed behavioral and physiological mechanisms to cope with the lack of water. Students might mention:
- Which "plans" seemed to work best? Why?
- What evidence do you have?
- Which "plans" didn't work well? Why?
- What evidence do you have?
- How does this activity help us learn about plant and animal survival in the desert?
- What types of things do you think plants and animals have that help them survive in dry places?
Have students revisit their original journal entries. Have them revise what they have based on what they learned from this activity. It is important that students use the knowledge they gained from this activity to answer the question.
Why should students communicate and justify their findings?
How can I help my students communicate and justify their findings?
- many desert plants have thick outer coverings, extremely long roots that help acquire moisture at the water table, or no leaves
- many animals that live in the desert are only active at dusk or dawn, burrow into the ground, or go into a type of hibernation where they only come out when it rains
Click here to find out how you can customize this lesson.
This lesson focuses on Questioning & Predicting, Explanations & Evidence, and Communicating & Justifying.
How Kirsten taught this lesson
While the lesson specifies that the sponge represents a desert-living organism in this activity, Kirsten also wants to make sure that her students understand what the outer coverings they're testing represent. She knows that organisms in dry climates have lots of different adaptations that allow them to conserve water and specialized outer coverings are just one.
Before starting the activity, she asked her students what is similar about all the materials on the supply table and how they were going to use them on their sponges. The student responses involved covering the sponges to keep the water in, and she asked what part of our bodies does this? The students said 'our skin' and Kirsten told them that the coverings represent the different 'skins' that this desert species could have. She showed the students a few living cacti and other desert plants that she has in the classroom and asked them to compare and contrast their outer coverings.