Unit 3 - KA6 Evolution Of Species

Question 1

What is a mutation?

Answer 1

A mutation is a random change to the genetic material, mutations are random ( can happen anywhere in the genetic material) and spontaneous ( can happen at any time)

Mutations are the only source of new alleles

Question 2

What does a mutation do?

Answer 2

-Confer an advantage for an organism to survive and reproduce
-Confer a disadvantage for an organism to survive and reproduce
-No effect on ability to survive and reproduce

Question 3

What can increase the rate of a mutation?

Answer 3

Radiation and chemicals

Question 4

What is the importance of a mutation?

Answer 4

-New alleles produced by mutations can result in plants or animals becoming better adapted to their environment
-Variation within a population makes it possible for a population to evolve, over time, in response to changing environmental conditions

Question 5

What is an adaption?

Answer 5

An adaption is an inherited characteristic that makes an organism well suited to survival in its environment

Question 6

What is natural selection?

Answer 6

1. Species produce more offspring than the environment can sustain
2. Natural selection or survival of the fittest occurs when more off spring are produced than the environment can sustain and when there are selection pressures
3. The best adapted individuals in a population survive to reproduce, passing on the favourable alleles, conferring an advantage to their offspring
4. These alleles increase in frequency within the population

Question 7

What is specification?

Answer 7

Specification is the formation of two or more species from the original one. For specification to occur, part of a population must become isolated from the rest of the species.

Question 8

What are types of isolation barriers?

Answer 8

-Geographical (mountain, desert, ocean, river, lake)
-Ecological (pH, temperature, humidity)
-Behavioural (differences in timing, location or complexity of mating rituals)

Question 9

Specification occurs after…

Answer 9

…part of a population becomes isolated by an isolation barrier

Question 10

Different mutations occur in…

Answer 10

…each sub population

Question 11

Natural selection selects for…

Answer 11

…different mutations in each group, due to different selection pressures

Question 12

Each sup population evolves until…

Answer 12

…they become so genetically different that they are two different species