9. Evolution

Question 1

Natural selection

Answer 1

Individual organisms within species show variation because of differences in their genes
Individuals with characteristics most suited to the environment are most likely to survive and reproduce successfully
Genes that enable these individuals to survive are passed on to the next generation.

Question 2

How are fossils formed?

Answer 2

When parts of organisms haven’t decayed because 1 or more conditions needed for decay are absent (Oxygen, moisture or warmth)
When parts of organisms are replaced by other materials (depositing materials) as they decay
Preserved traces i.e. foot prints or burrows

Question 3

How does Speciation occur?

Answer 3

Isolations: 2 populations of a species become separated
Genetic variation: Wide range of alleles
Natural selection: in each population advantageous alleles of survival selected
Speciation: Eventually the population becomes so different they can no longer reproduce resulting in fertile offspring