Year 7 Science · Unit 1 · Lesson 20
Challenge Worksheet
Learning Goals
Evaluate the claim
A student concludes…
"Our duckweed experiment proves that light is the only factor controlling plant growth. The duckweed in the dark container died after 7 days, which shows that without sunlight, no life can survive on Earth. Therefore, if you want any plant to grow fast, just give it more light."
(a) What part of this conclusion is correct and supported by the investigation results?
(b) Identify two logical errors or overstatements in the conclusion. Explain why each one is a problem.
(c) What additional evidence or further investigations would improve this conclusion?
1. Explain how a mutation affecting chlorophyll production in plant cells could cascade through to affect an entire ecosystem. In your answer, connect at least three scales: cell → organ system → ecosystem. Use specific examples.
2. A scientist investigating the koala's physiological adaptation to tolerate eucalyptus toxins finds that a new fungal disease is destroying koala liver cells. Using your knowledge of cells, organ systems, ecosystems, and biodiversity, predict and explain the potential consequences of this disease spreading through a koala population.
Wrap Up
What was the most surprising or interesting idea you encountered in Unit 1?