Genetic Diversity And Adaptation

Question 1

Genetic diversity definition

Answer 1

Number of different alleles of genes in a population that allows natural selection to occur

Question 2

Allele

Answer 2

Variations of a gene

Question 3

Natural selection process

Answer 3

A random mutation can result in new alleles of a gene which can be beneficial in the environment. This means that the possessor is more likely to survive and reproduce and their offspring will inherit this advantageous allele. Over generations this allele will increase in frequency in the population.

Question 4

Different types of adaptations

Answer 4

Anatomical, physiological and behavioural

Question 5

Anatomical adaptations

Answer 5

physical adaptations e.g giraffe’s long necks

Question 6

Physiological adaptations

Answer 6

Internal adaptations e.g bears metabolism slows down during hibernation

Question 7

Behavioural adaptations

Answer 7

An adaptation in behaviour e.g being nocturnal

Question 8

Directional selection

Answer 8

• favours 1 extreme phenotype
• normal distribution curve shifts towards this phenotype
• happens in a more extreme environment
• e.g antibiotic resistant bacteria

Question 9

Antibiotic resistance in bacteria

Answer 9

A random mutation creates a resistance allele in the bacterial population so only the bacteria with this allele will survive and reproduce when exposed to the antibiotic. Over generations the allele will become more frequent and all the bacteria will be resistant to that antibiotic.

Question 10

Stabilising selection

Answer 10

• the average phenotype is favoured
• variation of traits decreases over generations
• occurs in a non-changing environment
• e.g human birth weights

Question 11

Human birth weights

Answer 11

• middle birth weight has a selective advantage

- more likely to survive and reproduce to pass on allele to their offspring