Year 7 Science · Unit 1 · Lesson 10
Challenge Worksheet
Learning Goals
Odd one out
1. Circle the odd one out in each group. In the last column, name the level of the odd one out and the level of the other three.
| # | Group | Odd one out and reason |
|---|---|---|
| 1 | heart · stomach · leaf · blood | |
| 2 | neuron · red blood cell · muscle tissue · root hair cell | |
| 3 | circulatory system · digestive system · shoot system · lung | |
| 4 | human · gum tree · koala · palisade cell |
Find the errors
Noah’s answer
Question: Give an example at each of the five levels of organisation, from level 1 (smallest) to level 5 (largest), for the parts of the body that digest food.
Level 1: a muscle cell from the stomach wall.
Level 2: the stomach.
Level 3: muscle tissue.
Level 4: a very large stomach.
Level 5: a human.
2. Name the five levels. Then identify the errors in Noah’s answer, explain what is wrong with each, and rewrite levels 2 to 4 correctly.
Read the data
Scenario: a new heart
In a heart transplant, the nerves linking the heart to the brain are cut and do not reconnect straight away, but the new heart still beats on its own. Two adults did the same exercise test.
| Time | Person A (own heart) | Person B (transplanted heart) |
|---|---|---|
| At rest | 70 | 95 |
| After 1 minute of exercise | 110 | 100 |
| After 6 minutes of exercise | 130 | 122 |
Source: made-up values that follow the usual pattern for heart transplant patients.
3. Calculate how much each person’s pulse rose in the first minute of exercise.
Person A beats per minute
Person B beats per minute
4. Suggest why Person B’s heart was slow to speed up. What does Table 1 tell you about how the body’s systems rely on one another?
5. A surgeon replaces a patient’s diseased heart with a healthy donor heart. Using the levels of organisation, explain why a new organ is not enough on its own to keep the patient alive.
6. Someone claims: “Organs are the most important level of organisation. Everything smaller only builds them, and everything bigger is only organs teamed up. If you understand organs, you understand the body.” Evaluate this claim.
Odd one out
1. Row 1: blood, a tissue; the others are organs. Row 2: muscle tissue, a tissue; the others are cells. Row 3: lung, an organ; the others are organ systems. Row 4: palisade cell, a cell, not an organism; the others are whole organisms. 1 mark per row. [4 marks]
Find the errors
2. Levels: cell, tissue, organ, organ system, organism (1). Levels 2 and 3 are swapped: muscle tissue is the tissue, the stomach is the organ (1). Level 4 treats an organ system as a bigger organ; it is a group of different organs (1). Correct: tissue, stomach muscle tissue; organ, the stomach; organ system, the digestive system (mouth, stomach, intestines, liver) (1). [4 marks]
Question 3
A: 110 − 70 = 40 beats per minute (1). B: 100 − 95 = 5 beats per minute (1). [2 marks]
Question 4
The nervous system (1). A’s pulse rose by 40 in the first minute but B’s by only 5, reaching 122 only after 6 minutes (1). The heart beats on its own, but it needs the nervous system to change its rate quickly, so organ systems depend on each other (1). (B’s pulse still rises slowly because of chemicals in the blood; not expected.) [3 marks]
Question 5
The heart is one organ in the circulatory system, which also needs vessels and blood (1). That system depends on others: respiratory (oxygen), digestive (nutrients), nervous (heart rate) (1). The heart’s own cells and tissues must also stay alive, so every level matters (1). [3 marks]
Question 6
Marking guide: 1 position; 1 supported: organs such as the heart do vital jobs; 1 organs are built from tissues and cells; 1 systems do more than one organ and depend on each other; 1 an amoeba is an organism with no organs; 1 conclusion: every level depends on the others. [6 marks]
Model answer: The claim is only partly right. The heart does a vital job, but it is built from cardiac muscle cells and tissue, and it only works inside the circulatory system, which needs oxygen from the respiratory system. An amoeba has no organs but is alive. No level works alone.
Common error: treating an organ system as one large organ.