Year 9 Science · Unit 1 · Lesson 2
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Learning Goals
Odd one out
Circle the item that does not belong in each group. Then explain why it doesn't fit.
| # | Group | Your answer (odd one + reason) |
|---|---|---|
| 1 | Stimulus Receptor Effector Enzyme | |
| 2 | Sweat glands Kidneys Liver cells Hypothalamus | |
| 3 | Shivering Sweating Thirst A rise in blood glucose |
Real-world context
A red kangaroo in the outback cannot afford to lose water by sweating the way a human does. On a hot day it licks its forearms, where blood vessels run close to the surface of the skin, and the saliva evaporates and cools the blood underneath. It also seeks shade and stops moving during the hottest hours. A marathon runner in Sydney, by contrast, sweats heavily, and can lose several litres of water during a race, which is why runners are weighed before and after.
(a) The kangaroo and the runner use different effectors to solve the same problem. Name the stimulus they share, name each animal’s effector, and explain what both responses do to the stimulus.
(b) The runner’s temperature loop creates a problem for a second loop. Name that second loop and explain how it responds.
1. Two students on a hot day both measure 38.4 °C. One is sweating heavily; the other has stopped sweating and has dry skin. Decide which is in more danger and justify your answer using the loop rather than the number.
Wrap Up
In one sentence, what was the main idea of this lesson?