Topic 4 - Genetic Diversity

Question 1

What is an allele?

Answer 1

An allele is a variation of a gene that occupies a specific loci on a chromosome.

Question 2

What is genetic diversity?

Answer 2

The total number of different alleles in a population.

Question 3

How does genetic diversity lead to variation?

Answer 3

Genetic diversity leads to variation as different combinations of alleles mean different proteins are produced, resulting in different characteristics.

Question 4

How does genetic diversity influence natural selection?

Answer 4

Genetic diversity influences natural selection as organisms with advantageous traits are more likely to survive, reproduce, and pass on their alleles, influencing the gene pool. The more successful an organism is at reproducing, the more likely its alleles will be passed on to the next generation, increasing the allele frequency.

Question 5

What are the five key steps in natural selection?

Answer 5

1) There is variation in characteristics within a species.

2) More genetic variation emerges within a population due to random mutations.

3) Individuals with alleles that code for advantageous characteristics are more likely to reproduce.

4) These advantageous alleles are passed down to offspring.

5) Overtime, these beneficial alleles become more common in the population.

Question 6

What are the two types of selection?

Answer 6

1) Directional
2) Stabilising

Question 7

What are the favoured phenotypes in directional selection?

Answer 7

Extreme phenotypes

Question 8

What effect does directional selection have on the normal distribution curve?

Answer 8

Shifts the curve in the direction of the favoured extreme.

Question 9

What is an example of directional selection?

Answer 9

Antibiotic resistance in bacteria, where the resistant bacteria survive and reproduce.

Question 10

What are the favoured phenotypes in stabilising selection?

Answer 10

Average phenotypes

Question 11

What effect does stabilising selection have on the normal distribution curve?

Answer 11

Narrows the curve

Question 12

What is an example of stabilising selection?

Answer 12

Human birth weight, where infants’ weight have higher survival rates.

Question 13

What are adaptations?

Answer 13

Inherited characteristics that enhance an organisms ability to survive and reproduce in its specific environment.

Question 14

What are the three categories for adaptation?

Answer 14

1) Anatomical
2) Behavioural
3) Physiological

Question 15

What is an anatomical adaptation?

Answer 15

Physical structures both internal and external that aid an organism’s survival.

Question 16

What is a behavioural adaptation?

Answer 16

Activities and responses, whether inherited or learned that increase an organism’s chances of survival and reproduction.

Question 17

What is a physiological adaptation?

Answer 17

Internal biological functions that give organisms an edge in survival.

Question 18

Examples of anatomical adaptations…

Answer 18

1) Body coverings - Fur, feathers, scales protect organisms and support their survival.

2) Camouflage - Organisms with colouration that blends into their environment are less likely to be detected.

3) Mimicry - Some species imitate the appearance of more dangerous ones for protection.

4) Teeth - The shape of an animal’s teeth are adapted to its diet.

Question 19

Examples of behavioural adaptations…

Answer 19

1) Defensive responses - For example, opossums play dead and rabbits freeze to avoid detection by predators.

2) Courtship displays - For example, male scorpions dance to attract mates.

3) Seasonal actions - For example, migration helps birds access resources year-round and hibernation helps bears conserve energy when food is scarce.

Question 20

Examples of physiological adaptations…

Answer 20

1) Venom - Used by snakes to immobilise prey and by plants to deter herbivores.

2) Antibiotics - Produced by bacteria to outcompete rival species.

3) Water storage - Desert frogs can survive for over a year without a water source by storing water in their bodies.