Evidence for evolution

Question 1

Fossil

Answer 1

remnants of plants and animals preserved in rock

Question 2

Fossil record

Answer 2

Evidence that organisms have gradually changed over time according to sequences of fossil layers

Question 3

How do fossils form?

Answer 3

1. Animal dies and falls to the ground
2. Flesh rots, leaving the skeleton to be covered in sand or soil and clay before it is damaged
3. Protected, over millions of years, the skeleton becomes mineralised and turns to rock. The rocks shift in the earth with the fossil trapped inside
4. Eventually the fossil emerges as the rocks move and erosion takes place

Question 4

How does the fossil record provide evidence of the theory of evolution?

Answer 4

• Fossils of the simplest organisms such as bacteria are found in the oldest rocks whereas fossils of more complex organisms like vertebrates are found in more recent rocks which supports the theory that simple life gradually evolved into more complex life.
• Plant fossils appear before animal fossils which is consistent with the fact that animals require plants to survive.
• Closely related organisms had to have evolved from the same ancestor by studying the similarities in anatomy between similar species.

Question 5

What are the disadvantages in the fossil record?

Answer 5

• There are gaps in the fossil records as many organisms are soft-bodied and decompose quickly before they have a chance to fossilise.
• Many other fossils have been destroyed by volcanic eruptions.
• Some fossils are waiting to be discovered.