Year 7 Science · Unit 1 · Lesson 10
Apply Worksheet
Learning Goals
Order the steps
Number the levels from 1 (smallest) to 6 (largest) to show the correct order of biological organisation using a plant example. One step goes beyond the organism — think carefully about what it represents.
| Order (1–6) | Level / Example |
|---|---|
| Leaf — a flat structure containing palisade tissue, spongy mesophyll tissue, and vascular tissue all working together to capture sunlight and make food. | |
| A plant community or ecosystem — many plant organisms and other species living and interacting in the same environment (e.g. an Australian eucalypt forest). | |
| Palisade mesophyll tissue — a layer of tightly packed, chlorophyll-rich cells just below the upper surface of the leaf, specialised for photosynthesis. | |
| A single photosynthetic cell — one palisade cell containing chloroplasts that trap light energy and convert it into glucose. | |
| Shoot system — all the stems and leaves of the plant working together to collect light, carry out photosynthesis, and distribute sugar. | |
| A whole plant organism — for example, a scribbly gum tree, made up of both the root system and the shoot system combined. |
Read the graph
Study the bar chart showing the approximate number of organ systems in different organisms, then answer the questions below.
Data: adapted from comparative animal biology literature (e.g. Hickman et al., Integrated Principles of Zoology, 16th ed.)
(a) Describe the overall trend shown in the graph. What happens to the number of organ systems as you move from a bacterium to a human?
(b) What does this trend suggest about the relationship between an organism's biological complexity and the number of organ systems it has?
(c) Why does a bacterium have zero organ systems? Use what you know about the levels of organisation in your answer.
1. A student says, "A leaf is just a tissue." Using the levels of organisation, explain why this statement is incorrect. Name the correct level and justify your answer.
2. The digestive system includes the stomach, small intestine, liver, and mouth. Explain why these organs are grouped into a single organ system rather than described separately.
Wrap Up
In one sentence, what was the main idea of this lesson?