Year 10 Science · Unit 1 · Lesson 5
Challenge Worksheet
Learning Goals
Evaluate the claim
Someone claims...
"All mutations are harmful changes to the genetic code and should be corrected or eliminated wherever possible. Mutations are essentially mistakes, DNA damage that disrupts normal protein function and causes disease. There is no positive role for mutations in living things."
(a) What part of this claim is supported by the science you've learned? Give two specific examples where mutations have harmful effects on organisms.
(b) What is misleading or missing from this claim? Explain the role of neutral mutations and give at least one example of a beneficial mutation that has been important in the history of life on Earth or in a species' survival.
(c) The cheetah population went through a severe genetic bottleneck around 10,000 years ago, leaving all cheetahs today with very similar DNA. Why is low genetic diversity a problem for a species? How does this relate to the importance of mutations in maintaining population diversity over time?
1. The sickle-cell allele in haemoglobin is caused by a single base substitution mutation. In individuals with two copies (homozygous), it causes a debilitating blood disorder. Yet the allele remains common in populations from malaria-prone regions of Africa and Asia. Explain how a harmful mutation can persist, and even increase, in a population. What does this reveal about the interaction between mutations, environment, and natural selection?
2. A scientist proposes using CRISPR gene-editing technology to "fix" all known harmful mutations in human embryos before birth. Identify one scientific benefit and one scientific concern with this proposal. Then explain one ethical issue that this raises beyond the science.
Wrap Up
In one sentence, what was the main idea of this lesson?