Variation and Evolution Past Mock Questions

Question 1

What is meant by the term evolution?

Answer 1

Evolution is the way in which living things change genetically to produce new forms of life over long periods of time

Question 2

“Variation in a species can be caused by mutations”.

Is this statement true or false.

Answer 2

This statement is true as mutations can alter genes which will produce a recessive allele i.e. mutations can cause a change in genotype however the recessive may not be expressed.

Question 3

State any one agent responsible for increased mutation rates

Answer 3

Gamma rays

Ultra violet rays

Question 4

Name both scientists responsible for the Theory of Natural Selection

Answer 4

Charles Darwin

Alfred Russel Wallace

Question 5

Give a brief outline of the evidence for the Theory of Natural Selection from any one named source
(4)

Answer 5

Palaeontology - the study of fossils

The evolution of the horse

The horse gradually became taller over 60 million years - it used to be only about 0.4 M tall according to fossils but out modern day horse is approx. 1.6M tall

Fossils gathered show a gradual increase in horse height over time

Question 6

Explain the term variation

Answer 6

Variation within a species means that in a group of successfully interbreeding organisms the individual members show different characteristics

Question 7

Apart from mutation, state one other cause of variation

Answer 7

Sexual reproduction

Question 8

Explain the term chromosome mutation

Answer 8

A chromosome mutation is a large change in the structure or number of one or more chromosomes

Question 9

Explain what is mean by mutation

Answer 9

A mutation is a spontaneous or sudden change in the amount or structure of DNA

Question 10

“Most mutations are not passed on from one generation to the next.”

Explain this statement

Answer 10

Many mutations produce no change in the characteristics of a diploid organism

This is because the dominant allele on the second homologous chromosome can still produce the original protein

Question 11

Explain what is meant by species

Answer 11

A species is a group of similar organisms that are capable of naturally interbreeding with each other to produce fertile offspring

Question 12

State two causes of variation

Answer 12

Sexual reproduction

Mutations

Question 13

What is the significance of inherited variation in evolution?
(2)

Answer 13

Inherited variations are controlled by genes

This type of variation allows for the production of new genotypes which allows for evolution by natural selection

Question 14

Give a brief account of the Theory of Natural Selection

Answer 14

Overbreeding - organisms produce large numbers of offspring

Population numbers remain constant - the population is an area will continue to increase until the environment can no longer support any more - then the number will stay the same (approx.)

Struggle for existence - the more offspring formed the less the environment can support them - competition - example

Inherited variations - members of a population/species show genetic or inherited differences - may arise from sexual reproduction, mutation or genetic engineering

Conclusion - natural selection -organisms with variations that enable them to adapt better to their environment will survive and reproduce - organisms with unfavourable variations will not survive - survival of the fittest - Definition

Question 15

Define natural selection

Answer 15

The process by which those organisms with genetically controlled characteristics that allow them to be well adapted to their environments will survive and reproduce to pass on their genes to following generations