B15.5 Evidence For Evolution

Question 1

What is a fossil ?

Answer 1

The persevered remains of a previously existing organism

Question 2

What are the three different types of fossil ?

Answer 2

Mineral replacement ( classic fossil)
Impressions on rock
Preserved ( insects in amber)

Question 3

What are the four steps of fossil formation/ fossilization ?

Answer 3

1. Organism dies and is buried under a layer of earth
2. Soft tissue decays and hard tissue remains Eg bones and teeth
3. Pressure deep underground causes minerals to replace the bones (mineralization)
4. A mineral cast of the bones/ hard tissue remains and discovered many years later as fossils

Question 4

What are the four conditions required for fossilization ?

Answer 4

No O2
Pressure
Low temp
Hard tissue

Question 5

Why is the fossil record incomplete ?

Answer 5

Early life forms were soft bodied meaning they couldn’t form fossils

Destroyed due to geological activity such as Volcanos and plate movement

Some haven’t been found