2.2 evolution

Question 1

Evolution definition

Answer 1

The gradual change in the characteristics of a species over generations caused by natural selection, sexual selection and genetic drift.

Question 2

Genetic drift definition

Answer 2

The random change in the frequency of alleles in a population.

Question 3

Where is genetic drift significant

Answer 3

In small populations where alleles can be lost easily.

Question 4

Natural selection

Answer 4

The non random increase in the frequency of advantageous alleles which will increase the chance of survival and the non random decrease in the decrease of deleterious alleles which cause harm to an organism.

Question 5

Source of new alleles in a population

Answer 5

Mutation

Question 6

Hardy Weinberg formula

Answer 6

P2+ 2pq +q2 =1
p+q =1

Question 7

P value hardy Weinberg

Answer 7

Frequency of dominant allele

Question 7

q value hardy Weinberg

Answer 7

Frequency of recessive allele

Question 8

P2 value hardy Weinberg

Answer 8

Frequency of dominant homozygous genotype

Question 8

Q2 value hardy Weinberg

Answer 8

Frequency of recessive homozygous genotype

Question 9

2pq value hardy Weinberg

Answer 9

Frequency of dominant heterozygous genotype

Question 10

P2 + 2pq

Answer 10

Frequency of dominant phenotype.

Question 11

How can a mutation effect the fitness of an individual

Answer 11

Mutations can cause new alleles to appear in a species which can increase the chance of an individual surfing and reproducing or decrease the chance of an organism surviving and reproducing.

Question 12

Factors affecting rate of evolution

Answer 12

Mutation rate
Generation time
Metabolic rate
Gene transfer

Question 13

Mutation rate effect on evolution

Answer 13

The species will have more random and spontaneous changes in their genetic information resulting in more advantageous new alleles appearing in the species, evolution will occur faster.

Question 14

Generation time effect on evolution

Answer 14

Faster generation time means faster genetic drift and natural selection, meaning there is a greater change in the species faster, meaning evolution will occur faster.

Question 15

Metabolic rate effect on evolution

Answer 15

Higher metabolic rate means smaller body size and higher temperature - which has been found to produce higher mutation rate.

Question 16

Gene transfer effect on metabolic rate

Answer 16

Horizontal gene transfer can allow for advantageous genetic traits to be passed on immediately to organisms of the same generation.
Vertical sexual gene transfer can be used to increase variation and increase the rate of evolution.

Question 17

Fitness definition

Answer 17

The measure of how effective a particular genotype is at leaving offspring in the next generation relative to other genotypes.

Question 18

Why is natural selection non random

Answer 18

Because the organisms with the highest fitness will survive and reproduce passing on their genes, whereas other organisms will die off.

Question 19

Sexual selection definition

Answer 19

A form of natural selection, where the non random increase in an allele in the next generation is determined through the selection of mating partners.

Question 20

Sexual dimorphism

Answer 20

Where there is a distinct physical difference in males and females in a species.

Question 21

How does sexual selection occur

Answer 21

male - male rivalry for a female, the males will compete for the female.
The female will assess the fitness of the male.
Characteristics such as increased size and weaponry can increase access to mates.

Question 22

Genetic drift process

Answer 22

A bottleneck effect will decrease the population size and genetic variation.
The surviving population will reproduce together with their limited genetic variation.
The species will make a recovery with limited genetic variation.

Question 23

Selection pressure

Answer 23

A factor resulting in natural selection

Question 24

Absolute fitness

Answer 24

The ratio of frequency of a particular genotype between different generations.

Question 25

Relative fitness

Answer 25

The ratio of frequency of a particular genotype compared with the most succesful genotype

Question 26

Absolute fitness formula

Answer 26

Absolute fitness = frequency after selection / frequency before selection.

Question 27

Relative fitness formula

Answer 27

Number of offspring per individual of one genotype
/ number of offspring per individuals of most successful genotype.

Question 28

Relative fitness =1

Answer 28

Means the genotypes you are looking at is the most successful genotype.

Question 29

Relative fitness >1

Answer 29

Impossible

Question 30

Relative fitness <1

Answer 30

The genotype is not the most successful genotype in the species.

Question 31

Absolute fitness of >1

Answer 31

The frequency of the allele in the species is increasing (increasing fitness)

Question 32

Absolute fitness <1

Answer 32

The frequency of the allele in the species is decreasing (decreasing fitness)

Question 33

Absolute fitness =1

Answer 33

The frequency of alleles in the species in remaining constant
(Constant fitness )

Question 34

Symbiosis

Answer 34

Where two different species interact and have a relationship with each other.

Question 35

Parasitism

Answer 35

A symbiotic relationship between a host organism which is an organism which is detrimentally affected by the relationship, and an organism which benefits from the relationship by gaining energy or nutrients.

Question 36

Mutualism

Answer 36

A symbiotic relation between two organisms which both benefit from the relationship.

Question 37

Commensalism

Answer 37

A symbiotic relationships where one organism benefits and the other organism has no positive or negative effect.

Question 38

Co evolution definition

Answer 38

Where two different species that interact closely and undergo a change in their characteristics due to selection pressures imposed on each other.

Question 39

Red queen hypothesis

Answer 39

Red queen theory occurs between parasite and host.
A parasite will mutate to become better adapted to exploiting its host.
This will allow the high fitness mutant to survive and pass on its genes to the next generation.
This will increase selection pressure of parasite burden in hosts.
Then when advantageous alleles arise in the host through mutation these organisms will survive and pass on their genes.
This will allow the next generation to become better adapted to the parasites adaptation.
Causing evolutionary arms race.