Year 9 Science · Unit 2 · Lesson 19
Foundation Worksheet
Learning Goals
Match each term to its meaning
Write the letter of the correct meaning next to each term. Each letter is used once.
| Term | Letter | Meaning |
|---|---|---|
| Microplastic | A. The concentration of a substance rises at each higher level of a food chain. | |
| Photodegradation | B. An animal at the top of its food chain, with no natural predators. | |
| Bioaccumulation | C. A piece of plastic smaller than 5 mm. | |
| Biomagnification | D. A substance builds up inside one organism over its lifetime. | |
| Food chain | E. Breaking down a material with ultraviolet (UV) light. | |
| Apex predator | F. A sequence of organisms in which each one is eaten by the next. |
1. Name two ways that tiny pieces of plastic are released as people go about daily life. Say where each kind of piece ends up.
Because… chain
Fill in the empty boxes to follow one fibre from a jacket into a fish.
2. A mussel feeds by filtering large amounts of sea water. Explain why a mussel can end up with a higher concentration of microplastic than the water around it. Name the process.
Data: a pollutant moving up a food chain
Harmful chemicals called PCBs stick to the surface of microplastics in the sea, and they are stored in animals’ fat. Table 1 shows PCB levels in a model ocean food chain.
| Organism | What it eats | PCBs (ng per g of tissue) |
|---|---|---|
| Phytoplankton | makes its own food | 1 |
| Zooplankton | phytoplankton | 5 |
| Small fish | zooplankton | 40 |
| Tuna | small fish | 300 |
| Shark | tuna | 1500 |
Sample data for a model food chain, made up for this question. ng = nanogram.
3. How many times higher is the PCB level in the shark than in the zooplankton? Show your working.
Answer times
4. The shark never eats phytoplankton, yet it has the highest PCB level. Explain why, using the words bioaccumulation and biomagnification.
Scenario: after the storm
A class sampled the water in a creek below a busy road on a dry day, and again the morning after heavy rain. The water after the rain held many more black rubbery particles.
5. Suggest what the black particles are and where they came from. Explain why there were more of them after the rain.
6. Explain why stopping plastic before it reaches the ocean works better than trying to clean up microplastics once they are there. Use the size of the particles, how far they spread, and what happens to them in food chains.