1.7 Evolution

Question 1

What is evolution?

Answer 1

Evolution is the changes in organisms over generation as a result of genomic variation

Question 2

What is natural selection?

Answer 2

Natural selection is the non-random increase in frequency of DNA sequences that increase survival and the non random reduction in the frequency of delerious sequences

Question 3

Most characteristics of organism are controlled by many genes, what word is used to describe this?

Answer 3

Polygenic

Question 4

What are examples of selection types

Answer 4

Stabilising selection, directional selection and disruptive selection

Question 5

Horizontal transfer

Answer 5

Where genes are transferred between individuals in the same generation

Question 6

Vertical transfer

Answer 6

Genes a transferred parent to offspring as a result of sexual or asexual reproduction

Question 7

Species

Answer 7

A group of organisms that can interbreed to produce fertile offspring, and which does not usually breed with other groups

Question 8

Speciation

Answer 8

The generation of new biological species by evolution as a result of isolation, mutation, and selection

Question 9

Why are isolation barriers important in speciation?

Answer 9

They prevent gene flow between sub-populations during speciation

Question 10

Allopatric speciation

Answer 10

Gene flow between two or more populations is prevented by a geographical barrier

Question 11

Sympatric speciation

Answer 11

Two or more populations live in close proximity in the same environment but still become genetically isolated

Question 12

Why does sympatric speciation occur

Answer 12

Due to a behavioural or ecological barrier

Question 13

Stabilising selection

Answer 13

Average phenotype is selected and extremes survive much less

Question 14

Disruptive selection

Answer 14

Extreme values of phenotypes are chosen and average are selected against

Question 15

Directional

Answer 15

One extreme value or phenotype is selected over both average and the other extreme