Year 10 Science · Unit 1 · Lesson 11

Diversity of Life and Evolutionary Thinking

Challenge Worksheet

Name

Date

Class

Learning Goals

Evaluate how the absence of fossil evidence would have affected acceptance of Darwin's theory in 1858.
Analyse the role of multiple independent lines of evidence in establishing scientific credibility.
Explain how modern DNA evidence strengthened a theory proposed before molecular biology existed.

Go Deeper

What if…?

Scenario

Darwin published On the Origin of Species in 1859. His argument rested on observations from the Galapagos Islands, comparative anatomy, artificial selection in domestic animals, and the geological record showing ancient life. But imagine that Darwin had published in 1858, before any usable fossil record of transitional forms was known, and 90 years before the discovery of DNA. He had only his naturalist observations and the pattern of variation he saw in living animals. Without fossil evidence, could the theory of evolution by natural selection have been accepted by the scientific community?

Using what you know from this lesson about the evidence for evolution, predict and explain whether natural selection would have been accepted without fossil evidence. Consider: (1) what evidence Darwin did have, (2) what objections scientists would have raised, and (3) what type of evidence eventually silenced most critics.

Challenge 4 marks

Show What You Know

1. The Ediacara Hills in South Australia contain fossils of the earliest known complex multicellular organisms, dated to 560 million years ago. Explain how the existence of these fossils supports the tree of life model of evolution, and why a creationist model would struggle to explain them.

Challenge 4 marks

2. Humans share approximately 50% of their genes with bananas. A student says this proves evolution is wrong, "we are obviously nothing like a banana." Construct a scientifically accurate response explaining what shared genes actually indicate, and why the percentage of shared DNA is meaningful.

Challenge 3 marks

Wrap Up

In one sentence, explain why a scientific theory that is supported by multiple independent lines of evidence is more robust than one supported by only one type of evidence.