Evolution of species

Question 1

State the definition of a mutation

Answer 1

A mutation is a random change in the genetic material of an organism

Question 2

State three possible effects that mutations can have on an organisms survival

Answer 2

Mutations can be neutral (have no impact)
-Advantageous (increases)
-Disadvantageous (decreases)

Question 3

What is a mutagenic agent

Answer 3

A mutagenic agent is an environmental factor that increases the rate of mutation

Question 4

Give examples of environmental agents that increase the rate of mutation

Answer 4

• Radiation (UV)
• Chemicals (mustard gas)

Question 5

Explain the role of mutation in driving the process of evolution

Answer 5

Mutation results in new alleles being formed so creating genetic variation within the population. This then means that organisms have new characteristics that make them better adapted to their enviornment

Question 6

Explain why variation within a population is important for evolution

Answer 6

Genetic variation within a population is important because it provides a range of genetic material for natural selection to act on. The greater the variation within a population the greater the chance of long-term survival of the species

Question 7

Define the term adaptation

Answer 7

An adaptation is an inherited characteristic that makes an organism well suited to survival in its environment/niche

Question 8

What is stage one of natural selection

Answer 8

• Species produce more offspring than the environment can sustain

Question 9

What is stage two of natural selection

Answer 9

Natural selection (survival of the fittest) occurs when there are selection pressures action on the population

Question 10

What is stage three of natural selection

Answer 10

Examples of environmental change/selection pressures include: Food availability, Predators, disease, pollution ect

Question 11

What is stage four of natural selection

Answer 11

The best adapted individuals survive to reproduce passing on the favourable alleles that confer to the selective advantage to the next generation

Question 12

What is stage five of natural selection

Answer 12

Those individuals with disadvantageous alleles are less likely to survive and so their alleles will become less frequent within the population form generation to generation

Question 13

Define the term speciation

Answer 13

Speciation is the formation of new species during evolution

Question 14

Identify three types of isolation barriers

Answer 14

• Geographical
• Ecological
• Behavioural

Question 15

Give examples of each type of isolation barrier

Answer 15

Geographical - mountain ranges, rivers, seas
Ecological- PH, salinity, different habitats
Behavioural- Breeding season

Question 16

What is natural selection

Answer 16

The process by which organisms that are better adapted to their enviorment, survive, breed and pass on their favourable alleles that confer a selective advantage