3.4.4 Genetic Diversity And Adaptation

Question 1

What is genetic diversity?

Answer 1

The total number of different alleles within a population

Question 2

What is a gene pool?

Answer 2

The total number of all the alleles of all the individuals in a population at a set time

Question 3

What is allele frequency?

Answer 3

The proportions of the different alleles in the gene pool

Question 4

Define population.

Answer 4

Group of individuals of the same species that live in the same place at the same time

Question 5

Define species.

Answer 5

Individuals that can be interbred to produce fertile offspring

Question 6

How do individuals within a species differ?

Answer 6

In the combination of their alleles

They have the same genes

Question 7

Why is genetic diversity good for survival within a population?

Answer 7

There is more variety and so more alleles

If the environment changes there is higher chance if there beef a gene that aids survival within the species

Question 8

Define gene.

Answer 8

A section of DNA that codes for one polypeptide

Question 9

What is natural selection?

Answer 9

Organisms that have certain alleles that make them better adapted to their environment survive and breed which increases the frequency of those advantageous alleles in the next generation

Question 10

What can allele frequency?

Answer 10

Difference between the reproductive success of individuals

Changes in environment

Question 11

Describe the process of natural selection.

Answer 11

Random mutation of an allele results in a new allele of a gene
If the gene is advantageous the individual will be more likely to survive
They obtain better resources and so live longer so have more time to breed
The individual reproduction get successfully will pass on the allele to offspring
The frequency of this allele in the population increases as those who possess it survive and reproduce

Question 12

What are the key stages of natural selection?

Answer 12

Variation
Mutation
Environmental changes
Some survive
Reproduce
Allele

Question 13

What are the two types of selection?

Answer 13

Directional selection

Stabilising selection

Question 14

What is direction selection?

Answer 14

Where individuals that vary in one direction from the mean of the population are favoured
Changes the characteristics of the population

Question 15

What is stabilising selection?

Answer 15

Average individuals are favoured

Preserves the characteristics of the population

Question 16

Define phenotype.

Answer 16

The observable physical and biochemical characteristics of an organism

Question 17

How does directional selection occur?

Answer 17

Environment changes
Phenotypes best suited survive
Some individuals to the left or right of the mean will have a better suited phenotype
These individuals are more likely to survive, breed and pass on the phenotype to offspring
Over time the mean moves in the direction of these individuals (as they contribute more offspring than others)

Question 18

How can bacteria become resistant to antibiotics?

Answer 18

Bacteria mutates
New strain is resistant to antibiotics
New strain reproduces more quickly until it is the majority population

Question 19

How did mutated bacteria resist penicillin?

Answer 19

A mutation occurred in the allele of a gene in a bacterium that allowed it to make a new protein that breaks down penicillin before it can kill the bacteria
The enzyme is called penicillinase

Question 20

How did the bacteria that could produce penicillinase become the majority population?

Answer 20

It broke down the penicillin
The penicillin killed the non resistant bacteria
The resistant bacteria reproduced by binary fission
The frequency of the allele that enabled the production of penicillinase increased as the others decreased

Question 21

When does stabilising selection occur?

Answer 21

When environmental conditions remain constant

Individuals with protons closed to the mean are favoured

Question 22

What are the three types of adaptation?

Answer 22

Anatomical
Physiological
Behavioural