Key Area 6: Evolution of species

Question 1

What is mutation

Answer 1

a random change to genetic material

Question 2

what is genetic material

Answer 2

DNA

Question 3

what is the source of new alleles

Answer 3

mutation

Question 4

What can a random change to genetic material be

Answer 4

neutral
confer an advantage
or disadvantage

Question 5

how is mutation rate increased?

Answer 5

when organisms are exposed to environmental factors

Question 6

what are the two environmental factors

Answer 6

radiation - uv rays, x rays
chemicals - mustard gas

Question 7

what are genes

Answer 7

sections of chromosomes coding for one characteristic

Question 8

what are alleles

Answer 8

different versions of a gene

Question 9

what do all members of a population show

Answer 9

variation

Question 10

what does variation result in

Answer 10

differences in genetic information an organism contains

Question 11

how have organisms evolved

Answer 11

variation

Question 12

what are adaptations

Answer 12

variations that make an organism more likely to survive

Question 13

What is natural selection known as?

Answer 13

Survival of the fittest

Question 14

When does natural selection occur

Answer 14

When there is competition/selection pressures

Question 15

What are the stages of natural selection

Answer 15

More organisms are born than can survive
The best adapted breed and pass on favourable alleles
Overtime, population evolves

Question 16

What is speciation

Answer 16

the formation of a new species over a very, very long time

Question 17

What are isolation barries (give two example)

Answer 17

Geographical - mountain range, river
Ecological - pH, salinity
Behavioural - Different breeding seasons

Question 18

Stages of speciation

Answer 18

A large population is split by barrier
Mutations occur
Natural selection occurs
Each sub-population evolve until they are two different species