Year 10 Science · Unit 1 · Lesson 12

Natural Selection, The Mechanism

Challenge Worksheet

Name
Date
Class

Learning Goals

Explain it to a Year 6 student

Imagine your Year 6 cousin asks: "Why can't doctors just keep using the same antibiotics? Why do new ones keep running out?" Use the sentence starters below to explain natural selection and antibiotic resistance clearly. Use real examples, no jargon, and no more than two lines per starter.

Starter 1: "The basic idea of natural selection is..."

Starter 2: "Imagine you have a jar of 100 bacteria. Most can be killed by an antibiotic, but a few can't because..."

Starter 3: "After you take antibiotics, the survivors reproduce and soon all the bacteria are like the survivors. This matters for medicine because..."

Starter 4: "One thing people often get confused about is thinking that bacteria decide to become resistant. The truth is..."

1. The Australian Commission on Safety and Quality in Health Care recommends that doctors prescribe antibiotics for the shortest effective duration. Using your knowledge of natural selection, construct an argument explaining why shorter courses reduce, but do not eliminate, the risk of resistance developing. Why is "eliminate" impossible?

Challenge 4 marks

2. The platypus has features shared with reptiles (egg-laying, venom), birds (bill shape) and mammals (fur, milk). A student says this proves natural selection is wrong because "it looks like evolution couldn't decide what to make it." Construct a scientifically accurate response explaining what the platypus's features actually demonstrate about evolution.

Challenge 4 marks

Wrap Up

In one sentence, explain why natural selection has "no foresight", it cannot plan for future challenges.