Key area 3.5 - Evolution

Question 1

Describe mutations

Answer 1

They’re random changes to genetic material

They can be neutral, advantageous or disadvantageous

They’re spontaneous and the only source of new alleles

Question 2

Name two environmental factors that can increase the rate of mutation

Answer 2

Radiation ( uv light + x-rays )

Chemicals ( mustard gas )

They’re known as mutagenic agents

Question 3

What is variation ?

Answer 3

Differences between living things in the same species

Variation within a population makes it possible for a population to evolve over time in response to to changing environmental conditions

Question 4

Describe survival of the fittest

Answer 4

The individual most adapted to their environment will survive and pass their genes onto the next generation

Question 5

What factors are involved in speciation ?

Answer 5

Isolation barriers ( to create sub groups )

Favourable random mutations ( they’ll be different in each sub population)

Natural selection

Question 6

Name and give examples of the 3 isolation barriers

Answer 6

Geographical
Rive, Mountain, Sea

Ecological
PH, Different Habitats, Salinity

Behavioural
Different Mating Calls, Active at Different Times of Day