1.7

Question 1

What is evolution?

Answer 1

Evolution - the changes in organisms over generations as a result of genomic variations.
Evolution leads to offspring that are better adapted to survive in their environment than the previous generation.

Question 2

Vertical gene transfer (inheritance)

Answer 2

• the transfer of genes down from parent to offspring
• this takes place either by sexual or asexual reproduction
• happens in both eukaryotes and prokaryotes

Question 3

Horizontal gene transfer

Answer 3

• genes are transferred across from one cell to another within the same generation
• prokaryotes (bacteria) can exchange genetic material horizontally between members of the same population. This results in variation within a species of bacteria.
• the horizontal exchange of genetic material between prokaryotes (bacteria) can result in rapid evolutionary change

Question 4

Definition of natural selection

Answer 4

Is the non-random increase in frequency of DNA sequences that increase survival and the non-random reduction in deleterious sequences

Question 5

Sexual selection is the ___________

Answer 5

Non-random process of selection for traits that increase the reproductive success of the species

Question 6

Sexual selection operates in two ways:

Answer 6

Male to male competition

Female choice

Question 7

What is a species?

Answer 7

A species is group of organisms capable of interbreeding and producing fertile offspring, and which doesn’t normally breed with other groups

Question 8

Speciation is the _______ of ____ biological species by _______ as a result of ______, ______, and ______

Answer 8

Generation
New
Evolution
Isolation
Mutation
Selection

Question 9

Types of speciation and what they are

Answer 9

Allopatric - gene flow is prevented by a geographical barrier (river, mountain range, desert, sea)
Sympatric - 2 populations may live closely together but can become genetically isolated. May be because gene flow is prevented between them by the presence of a behavioural or ecological barrier or by the occur acne of polyploidy in plants. Sympatric speciation is promoted by disruptive selection

Question 10

Explain the formation and maintenance of zones of hybridisation

Answer 10

Hybrid zones form where the ranges of two closely related species interbreed and within these zones membranes of the two species overlap. The hybrid offspring are less fit (sterile) and are eliminated by natural selection. Membranes of each species re-colonise the hybrid zone; and undergo further hybridisation to repopulation the zone