ADAPTATION

Question 1

What is genetic diversity?

Answer 1

• Number of different alleles for genes in a population

* Genetic diversity allows natural selection to occur

Question 2

How does genetic diversity affect natural selection?

Answer 2

• Allows natural selection to occur

Question 3

What is the process of natural selection?

Answer 3

• Random mutation can result in new alleles of a gene.
• Many mutations are harmful but, in certain environments, the new
allele of a gene might benefit its possessor, leading to increased
reproductive success.
• The advantageous allele is inherited by members of the next
generation.
• As a result, over many generations, the new allele increases in
frequency in the population.

Question 4

How does natural selection occur?

Answer 4

• Genetic and phenotypic diversity exists in a population
• Some variation arises from mutation which creates a new allele for a gene
• Some new alleles equip the individual with an advantage
This individual is more likely to survive and reproduce
• The allele is passed down to its offspring
• Its offspring also have the survival advantage
• Organisms carrying this allele continue to survive and reproduce
• The allele is passed down generations
• The allele frequency increases within the population
• Population is better adapted to its environment

Question 5

What is directional selection?

Answer 5

directional selection is a mode of natural selection in which an extreme phenotype is favoured over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
One extreme trait is favoured

Question 6

What are some examples of types of adaptations from natural selection?

Answer 6

• Anatomical
• Physiological
• Behavioural

Question 7

What is an advantage of natural selection over other selections?

Answer 7

Results in species that are better adapted to their environment.

Question 8

What is stabilising selection?

Answer 8

• Environment favours individuals close to a specific value which doesn’t change
• Individuals with extreme phenotypes are less likely to survive
• Mean stays the same
• Standard deviation becomes smaller over time

Question 9

What is an example of stabilising selection with birth weights?

Answer 9

• Baby born too heavy, can lead to birth problems

* Baby born too small, can lead to developmental problems