Teacher sheet · Ages 10–11 · about 45–50 minutes
What makes a mammal?
Lesson page: echoesof.science/school/mammals/ages-10-11/ · Pupil worksheet: echoesof.science/school/mammals/ages-10-11/print/
Learning aims
- List the features that all mammals share.
- Describe monotremes, marsupials and placental mammals.
- Name the types of mammal teeth.
- Plan and carry out a fair test on insulation and present results as a line graph.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: how do seals stay warm in icy water without a coat? |
| 10 min | Read the text; sort pictures into the three groups. |
| 20 min | Blubber test and graph. |
| 5 min | Which group? game. |
| 5 min | Quiz and results discussion. |
Materials for the experiment
- Four zip-lock sandwich bags
- Vegetable shortening or lard (about 250 g)
- Two thermometers or temperature probes
- A large bowl of ice and cold water
- Sticky tape, spoon, paper towels
- Timer
Safety: Do not keep hands in ice water for more than a few seconds. Wipe up spills and fat straight away so the floor is not slippery. Check for food allergies before handling fats. Wash hands afterwards.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Whales and dolphins are big fish. | They breathe air, have hair (a little) and feed their young milk: they are mammals. |
| All mammals give birth to live babies. | Monotremes lay eggs. |
| Blubber makes heat. | Blubber slows heat loss; the heat comes from the animal's own body. |
Worksheet answers
- Monotremes (platypus or echidna); marsupials (kangaroo, koala or opossum); placental mammals (e.g. humans).
- Incisors, canines, premolars and molars.
- Changed: blubber or no blubber. Measured: temperature inside each bag every minute. Same: bags, starting temperature, time in the ice water, depth, the ice water.
- The temperature in the blubber bag dropped more slowly; the fat layer slows heat loss, so blubber keeps the seal's body warm in cold water.
Quiz answers
- Which two features do all mammals share? Hair and mammary glands. Mammary glands make milk.[1]
- Which mammals lay eggs? Monotremes, such as the platypus. The young hatch and drink milk.[1]
- Where do most marsupial babies grow after birth? In a pouch. Marsupial young are born very tiny.[1]
- Which teeth are not one of the mammal tooth types? Gills. Mammals have incisors, canines, premolars and molars.[1]
- What does blubber do? Keeps sea mammals warm and stores energy. Blubber is a thick layer of fat.[6]
- How do many bats find insects in the dark? By echolocation. They listen for echoes of their high sounds.[5]
Going further
Compare a skull or a picture of a dog's teeth and a sheep's teeth. Which teeth are big in a meat-eater, and which in a plant-eater?
Sources used in this lesson
- [1] Biology 2e, 29.6 Mammals (OpenStax (Rice University)): reliability High
- [3] Mammalia: mammals (BioKIDS, University of Michigan): reliability Medium-high
- [5] Bats (Yellowstone National Park) (U.S. National Park Service): reliability High
- [6] How marine mammals stay warm (hands-on activity) (NOAA Office of Education): reliability High
- [7] Biology 2e, 33.1 Animal form and function (OpenStax (Rice University)): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/mammals/sources/
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