Unit B: Living Things in Their Environment

Why doesn't a polar bear slip on the ice when it runs?

1. Get Set to Explore


  • adaptation: A body part or behavior that helps a living thing survive in its environment.
  • Arctic: The region of Earth that is near the North Pole; the Arctic is a cold environment with much ice and snow.
  • environment: All the living and nonliving things that surround an organism.
  • habitat: A place where an organism lives.

Building Background

  • Let volunteers describe where polar bears live, and list different traits polar bears have that allow them to live there. Write the list on the board.
  • Go over the vocabulary words and their definitions. Refer to the list of polar bear traits on the board and ask students to use it to find examples of some of the words. For example, the white fur of the polar bear is an example of an adaptation; the polar bear lives in the Arctic; its habitat is the snow-covered land and the icy water.
  • Explain that many different animals have feet that help the animal survive in a particular environment. Polar bears are one such animal. Tell students that in the simulation, they will learn how the feet of polar bears help the bears survive. The simulation teaches about adaptations other animals have, as well.
  • Present the Discover! question and encourage students to come up with answers. Write their ideas on the board. If possible, link their ideas to the list of polar bear traits that students generated earlier in the discussion. Keep both lists up on the board.

2. Guide the Exploration

  • Tell students to launch the Discover! Simulation. Explain that they will be matching each of five different feet to the environment that an animal with that type of foot has adapted.
  • Point out that students can learn more about each foot and each environment by moving the cursor over the picture of each and clicking. Students should spend some time studying the different feet before trying to match each to the correct environment. Encourage students to take notes based on what they learn from the simulation.
  • Go over how all of the five different feet help the animals adapt to particular environments. Students should refer to their notes from the simulation during the discussion.

3. Review/Assess

  • Review Step 3's Wrap-up text with the class. Refer to the lists of polar bear adaptations students made before doing the simulation, and allow students to add to or revise these lists. Talk about the specific adaptations polar bears have for running on ice: fur helps prevent slipping; paw size helps prevent polar bears from falling through thin ice.
  • Challenge students to do the Extension activity. Elicit this information in class discussion.
    • Polar bears have thick fur, which helps the bear survive in cold weather; their white color helps them blend into the snowy environment and to sneak up on their prey; having partially webbed feet makes it easier for the bears to swim.
    • Mallards have webbed feet, which makes it easier for them to swim; the webbing prevents the duck from sinking in mud; oiling the feathers waterproofs the bird.
    • Iguanas have clawed feet, which help them climb trees; they can also harm attackers with their claws.
    • Camels have broad, flat feet to prevent them from sinking in the sand; the leathery pads prevent the camel from being burned by the hot sand.
    • Mountain goats can have split hooves, which move separately to provide a good grip on steep or slippery rocks; they have pads on their feet, which also help prevent slipping; their wooly coat helps them stay warm in the cold environment.

If time permits, present students with the following activity and question:

  • Critical Thinking Classify List two adaptations of mallards that involve body parts; list two adaptations of mallards that involve behavior. Answer: The webbed feet and the ability to produce oil involve body parts; closing the toes to prevent the webbing from pushing against the water and rubbing oil on their feathers are adaptations involving behavior.
  • Inquiry Skill Compare Compare the adaptations of polar bears with those of mountain goats. How are they similar and how are they different? Answer: Polar bears have fur on their paws to prevent slipping on flat but slippery surfaces; mountain goats have split hooves that can move independently for better grip on steep, slippery surfaces. Both have thick coats of fur for warmth.

4. Reaching All Learners

On Level: Visual/Logical Learners

As students do the simulation, they should make a chart listing the different environments. Have students use the pictures to describe or figure out important features of each environment. Next, students should list the different types of feet and the different adaptations, noting how each might be useful. Then they should use their two lists to match each foot to the correct environment.