Year 10 Science · Unit 1 · Lesson 14

Evidence for Evolution, Molecular and Biogeographical

Challenge Worksheet

Name

Date

Class

Learning Goals

Evaluate the strength of DNA evidence for evolution and address counterarguments.
Discuss the limitations of using DNA similarity as proof of evolutionary relationships.
Assess whether a high percentage DNA similarity "proves" a theory or strongly supports it.

Go Deeper

Evaluate the claim

Someone claims...

"Because humans and chimpanzees share 98.8% of their DNA, and because DNA is the molecule of heredity, this DNA similarity conclusively proves beyond any doubt that humans and chimps share a common ancestor. Anyone who questions this claim simply does not understand genetics. The case for evolution is completely closed."

(a) What part of this claim is supported by scientific evidence? Be specific about what DNA similarity actually demonstrates.

Challenge 2 marks

(b) What is misleading or overstated in this claim? Consider how science works and what "proves" means in science.

Challenge 2 marks

(c) Name two other independent lines of evidence that, combined with DNA similarity, make the case for common ancestry of humans and chimps extremely strong.

Challenge 2 marks

Show What You Know

1. A common counterargument is: "DNA similarity between humans and chimps is just a coincidence, God designed them with similar DNA." Evaluate this counterargument scientifically. What would you need to observe for the DNA similarities to truly be coincidental?

Challenge 3 marks

2. The thylacine (Tasmanian tiger) looked like a wolf but was genetically a marsupial. Explain how this example illustrates both convergent evolution and the importance of molecular evidence over appearance alone.

Challenge 3 marks

Wrap Up

In one sentence, what was the main idea of this lesson?