Evolution

Question 1

What is a niche?

Answer 1

The specific unique role an organism plays in an environment

Question 2

What does it mean for an organisms to be adapted?

Answer 2

Means an organism is specialised to suit the environment they live in, organisms adapt t exploit their niche and ensure their niche is different enough to others to avoid competition

Question 3

What are the three types of adaptations?

Answer 3

Behavioural, physiological, anatomical

Question 4

What are behavioural adaptations and examples?

Answer 4

Actions taken by the organism which help them to reproduce or survive –> can be learnt or innate
- can be survival (pack hunting), courtship (mating calls) or seasonal (migration/hibernation)

Question 5

What are physiological adaptations and examples?

Answer 5

Biochemical adaptations, increase chance of survival by allowing correct functioning
e.g. concentration of urine in response to water shortages, chemical production of poison, production of antifreeze proteins

Question 6

What are anatomical adaptations and examples?

Answer 6

Physical adaptations e.g. camouflage, mimicry, blubber

Question 7

What observations did Darwin make about the world around him?

Answer 7

• organisms produce large number of offspring
• no two individuals are identical —> variation in members of the same species
• offspring generally look like their parents
• individuals best adapted to their environment are more likely to survive

Question 8

What are selection pressures?

Answer 8

Environmental factors determining which individuals of a species will survive

Question 9

Describe the steps of natural selection

Answer 9

1 variation within a population due to mutations/sexual reproduction
2 different environments with different selection pressures
3 only individuals with advantageous alleles will survive and reproduce
4 offspring may inherit advantageous alleles
5 over time proportion of pop. with advantageous alleles increase; may lead to evolution and formation of new species

Question 10

What is convergent evolution?

Answer 10

The process whereby organisms that are not closely related independently evolve to have similar features as a result of having to adapt to a similar environment

Question 11

Who worked with Darwin to create a paper on the Theory of Evolution?

Answer 11

Alfred Wallace

Question 12

Define evolution

Answer 12

The change in inherited characteristics of a group of organisms over time

Question 13

What is population genetics?

Answer 13

Investigates how allele frequency changes over time

Question 14

What is the Hardy Weinberg principle?

Answer 14

States: In a stable population with no disturbing factors the allele frequency will remain constant from one generation to another and there will be no evolution

Question 15

Which five conditions must be met for allele frequency to remain constant?

Answer 15

• No mutation
• No immigration/emigration
• no selection (no alleles favoured/eliminated)
• Random mating
  -Large population

Question 16

What equation for the Hardy Weinberg principle links alleles?

Answer 16

p + q = 1
p - dominant allele
q - recessive allele

Question 17

What equation for the Hardy Weinberg principle links genotypes?

Answer 17

p^2 + 2pq + q^2 =1
p^2 = homozygous dominant
2pq = heterozygous
q^2 = homozygous recessive