S4.3.2 For the adult
Evidence for evolution
How do we know that living things have changed over millions of years, when nobody was there to see it?
What this chapter teaches
Fossils are the remains or traces of living things from long ago. In rock layers that have not been moved, the oldest are at the bottom. The more alike the DNA of two species, the more recently they shared an ancestor. The fossil record has gaps because fossils form rarely.
Three questions to ask
There is no one right wording. Listen for the idea.
- Why are the oldest fossils usually at the bottom of a cliff of layered rock?
- What can DNA tell us that fossils cannot?
- Why is a gap in the fossil record not a reason to doubt evolution?
After the chapter, the learner can
- Explain how fossils and DNA show that species are related
- Explain why the fossil record has gaps
What they copy into their notebook
Fossils lie in layers, the oldest at the bottom. More alike DNA means a more recent common ancestor. The record has gaps, because few things become fossils.