B15 - Evidence for evolution Flashcards
1
Q
fossils
A
remains of organisms from millions of years ago
-found preserved in rocks, ice
2
Q
Fossil formation - absence of decay
A
- conditions of decay are not met
-little o2 or low temp or toxic gas to kill bacteria
3
Q
Fossil formation - minerals
A
- impessions of organisms is made in mud
- filled with minerals and become fossilised
4
Q
fossil formation - traces of organism
A
- footprints
- burrows
-droppings
5
Q
incomplete fossil record due to
A
- early life forms = soft bodied so little fossils
- destroyed due to volcanoes
- formation conditions were rare so little fossilised
6
Q
Fossil record
A
- shows changes in organisms
- development and environment of that time
7
Q
fossil record limitation
A
- small pieces were found only
8
Q
Extinction
A
permenent loss of all members of a species
9
Q
how does extinction occur
A
- conditions change
- less adapted species die out
- better adapted individuals survive
10
Q
Reasons for extinction
A
- change to environment
- temp
-new predator
-disease - successful competitors
- volcanoes
11
Q
Reasons for extinction - new predators
A
- wipes out prey if they cannot adapt to survive
12
Q
Reasons for extinction - new disease
A
- likely on islands where population in close together
13
Q
Reasons for extinction - successful competitor
A
- new mutations = advantage
- better suited
14
Q
geological time
A
changes of the environment /climate that take place over billions of yrs
15
Q
Fossil evidence on extinction
A
shows mass extinction
- caused by a single catastrophic event
