B14 - Genetics And Evolution Flashcards
1
Q
How are fossils formed?
A
1) -When impressions/ traces are left behind
2
Q
How are fossils formed?
A
2) -When hard parts become ‘mineralised’
3
Q
How are the fossil formed?
A
3) -When decay cannot happen
4
Q
Process of number 1
A
- some of the fossils found are not of actual animal or plant, but are preserved traces they have left behind
5
Q
Process of number 2
A
- this takes place over long periods
- many fossils are formed when harder parts of the animal or plants are replaced by minerals as they decay and become part of the rock
6
Q
Process of number 3
A
- happens when one or more of the conditions needed for the Decay are not there
- this can happen through little or no oxygen present
- poisonous gasses kill off the bacteria that cause decay
7
Q
What is the fossil record incomplete?
A
It is incomplete because most organisms that died did not become fossilised and The original life forms with softbodied (like worms) and had no skeletons.
