6.2

Question 1

What is variation?

Answer 1

Differences in the characteristic of individuals in a population.

Question 2

What are the causes for variation?

Answer 2

• Genetic: the genes they inherited (e.g. skin colour, eye colour)
• Environmental: the conditions in which they have developed (e.g. pH of soil determines colour flower, languages)
• A combination of genes and environment (e.g. height: includes alleles for tallness but enough calcium to reach full height).

Question 3

Where do all variants arise from?

Answer 3

Mutations that either, have no effect on phenotype, determine the phenotype (e.g. eye colour), influence the phenotype (e.g. alleles for tallness may lead to tallness if diet is good) or lead to a new phenotype (e.g. resistance to virus compared to most of species).

Question 4

What is the theory of evolution?

Answer 4

All species of living things have evolved from simple life forms that first developed more than three billion years ago.

Question 5

Explain how evolution takes place through natural selection.

Answer 5

1. When a change occurs to the environment, the population in a species with the most advantageous alleles for the situation will have a higher chance of living and reproducing.
2. This means it will out grow the other organism in it’s species with different less advantageous alleles, which are more likely to die.

Question 6

What is evolution?

Answer 6

A change in the inherited characteristic of a population over time due to natural selection.

Question 7

How can a species end up becoming two separate species?

Answer 7

If the phenotype of two populations of the same species have too much of a different phenotype, they can no longer interbreed fertile offspring and therefore become two separate species.

Question 8

What is meant by selective breeding?

Answer 8

The process at which humans breed plants and animals for particular genetic characteristics.

Question 9

Explain the impact of selective breeding of foods and domesticated animals.

Question 10

What is a disadvantage of selective breeding?

Answer 10

Can lead to inbreeding - some plants or animals become prone to disease or inherited defects.

Question 11

What is the process of selective breeding?

Answer 11

1. Breed parents from mixed population with desired characteristics.
2. Offspring with desired characteristics are bred.
3. Process continues until all offspring show desired characteristic.