Variation DNA and mutations

Question 1

What is variation

Answer 1

Variation is the difference in characteristics of organisms. It can be caused by genes an individual inherits or an environment it lives in

Question 2

What is a mutation

Answer 2

A mutation is a random change in DNA which therefore affects a gene and/or a chromosome. They can be inherited and passed on from one individual to another.

Question 3

What is natural selection

Answer 3

This is a process where organisms that are better adapted to an environment will survive and reproduce. This means that the advantageous alleles of this variant organism are passed down to the offspring.

Question 4

What is competition

Answer 4

Competition is an interaction between organisms or species in which both require a resource that is in limited supply. It drives the process of natural selection

Question 5

What is sexual reproduction

Answer 5

This involves the fusion of the nuclei of a male and female sex cell during fertilisation. The offspring inherit a mixture of alleles from both parents.

Question 6

What is asexual reproduction

Answer 6

This is when an exact genetic copy of the parent organism is produced ( a clone). This only produces genetic variation into the population if a random mutation in the organisms DNA is passed on to the offspring

Question 7

Advantages of sexual reproduction

Answer 7

Produces genetic variation in the offspring
A disease is less likely to affect the whole population

Question 8

Disadvantages of sexual reproduction

Answer 8

time and energy are needed to find a mate
It is not possible for an isolated individual to reproduce

Question 9

Advantages of asexual reproduction

Answer 9

It is more time and energy efficient
The population can increase rapidly in favourable conditions

Question 10

Disadvantages of asexual reproduction

Answer 10

There is no genetic variation in a population outside of mutations
Disease may affect the whole population

Question 11

Evidence for evolution

Answer 11

1.Evidence for early forms of life come from fossils. By studying fossils, scientists can learn how much organisms have changed as life developed on earth.
2. The development of antibiotic resistance in bacteria gives more evidence to support the theory of natural selection leading to evolution.

Question 12

What is selective breeding

Answer 12

This is when humans breed plants and animals for particular genetic characteristics so that they are different to their wild ancestors and useful to humans

Question 13

Main steps of selective breeding

Answer 13

Select important characteristics
Choose parents that show these characteristics from a mixed population and breed them together
Choose the offspring with the desired characteristics and breed these together to create the next generation.
Repeat over many generations until all offspring show the desired characteristics

Question 14

Advantages of selective breeding

Answer 14

More or better quality food
Animals can be selected to make them safer to humans

Question 15

Disadvantages of selective breeding

Answer 15

Reduced genetic variation can lead to attack by disease
Creating physical problems in specific organisms