Mechanism Of Evolution And Their Affects On Population

Question 1

What is genetic drift

Answer 1

changes to allele frequency as a result of chance events in the breeding population; such changes are much more pronounced in small populations

Question 2

What are the 2 causes of genetic drift?

Answer 2

Bottle neck effect
Founder effect

Question 3

What is the bottleneck effect

Answer 3

Drastic reduction in population size

Question 4

What is the founder effect

Answer 4

Small allele sample establishes a new population

Question 5

What is gene flow

Answer 5

Movement of alleles from one population to another

Alleles move through individuals or gametes

Question 6

What are the types of mutations

Answer 6

Point Mutation
Gene Duplication
Deletions
Insertions
Inversions

Question 7

Describe the link between mutations and evolution

Answer 7

1. Harmful mutations occur frequently but are selected against
   Thus, the mutant alleles are rare
2. Beneficial mutations are rare, but are selected for
   Thus, the mutant alleles accumulate

Question 8

What is non random mating

Answer 8

Mating among individuals is based on mate selection for a particular phenotype or due to inbreeding (artificial selection or self-fertilization).

Question 9

What are the types of selection?

Answer 9

1. Stabilizing Selection
   2.Directional Selection
   3.Disruptive Selection
   4.Sexual Selection

Question 10

What is stabilizing selection?

Answer 10

The most common phenotypes within a population are most favoured by the environment

Question 11

What is example of stabilizing selection

Answer 11

Human baby weight

Question 12

What is directional selection?

Answer 12

More extreme variations of a trait are favoured by the environment

Question 13

What is an example of directional selection

Answer 13

Industrial melanism in peppered moth

Question 14

What is disruptive selection?

Answer 14

The variations at opposite extremes of a trait over individuals with intermediate variations are favoured by the environment.

More than one phenotype is favoured and can result in isolated populations with separate gene pools.

Question 15

What is an example of disruptive selection

Answer 15

Finches with small
And big beaks

Question 16

What is sexual selection?

Answer 16

Related more to mating rather than the environment
Selection favours any trait that influences the mating success of an individual
a)Sexual dimorphism – ex. attractive coloured feathers
b)Behavioural differences between the sexes

Selected traits often increase success in competition.
Although they benefit mating chances, they are often detrimental/costly.