Question | Answer |
What is variation in a population due to? | To the existance of different alleles. |
How did different alleles come about? | By the process of mutation. |
What is speciation? | Speciation is the formation of two or more species from 1 original species. |
Give an example of speciation. | Darwin’s Finches in the Galapagos Islands are an example of speciation. |
What is a definition of a species? | Organisms of the same species can interbreed to produce fertile offspring. |
What are the steps of speciation? | Speciation is a three step process: isolating mechanism, mutation, natural selection. |
What is the role of isolating mechanism in speciation? | Isolating mechanisms prevent gene flow between two sub populations. |
Name 3 types of isolating mechanism. | Geographical, Ecological and Reproductive. |
How do mutations occur? | Randomly and at low frequency. |
How do mutations occur on either side of an isolating barrier? | Mutations are random and therefore occur only on 1 side of the barrier OR different mutations occur either side of the barrier. |
How does natural selection affect populations? | Selection pressure causes those with a selective advantage to survive, reproduce and pass on their successful alleles, the weaker organisms don't and so die out. |
Give one example of a natural selection in insects. | Peppered moth. The peppered moth died out as the black moth had camouflage as a selective advantage |
Give an example of a characteri offering natural selection advantage in humans. | Human skin colour with darker skin caused by melanin pigment offering a selective advantage in warmer climates. |
Antibiotic resistant bacteria are a product of | natural selection. |