Evidence of evolution: fossils, homologous and vestigial organs
Look at a shaligram from the Kali Gandaki, a bat's wing, the human appendix, Archaeopteryx and more. Find out what each tells us, and sort them by the kind of evidence for evolution they are.
Core concept
Living things have changed slowly over millions of years (organic evolution); fossils, homologous organs, vestigial organs and connecting links are evidence that today's species came from common ancestors
Topic: Evolution
Organic evolution is the slow change of living things over many generations, so that simple forms of life gave rise to all the species living today. Lamarck thought that animals pass on features they gain in their lifetime, such as a giraffe stretching its neck; Darwin showed instead that animals vary, and those with useful variations survive and breed more (natural selection). What is the evidence: What you saw or measured that shows whether an idea is right. All key words that evolution happened? Fossils are the remains of living things preserved in rock. Homologous organs have the same basic structure but do different jobs, showing a common ancestor. Vestigial organs are small, useless leftovers of organs that were useful to an ancestor. Connecting links are living things with features of two groups. In this lab you look at thirteen pieces of evidence and sort them.
What you will learn
- Define organic evolution.
- Describe fossils, homologous organs, vestigial organs and connecting links as evidence of evolution.
- Give examples of each, including the shaligram found in Nepal.
- Compare Lamarck's and Darwin's ideas about how evolution happens.
Before you start
- Know that living things inherit features from their parents.
Materials
- Pictures of fossils and of the arms of a human, a bat and a whale
Equipment
- A shaligram or another fossil, if your school has one
Procedure
- Pick a card and look at what it is and what it tells us.
- Do this for at least eight cards.
- Sort every card by the kind of evidence it is.