9.3 Genetic diversity and adaptation

Question 1

What causes genetic diversity?

Answer 1

• variations in DNA cause members of a species to have different characteristics.
• All members of a species have the same genes, which is why we can recognize them as that species
• but all members of a species have varying alleles, which is why they are able to be distinguished from one another.

Question 2

What is genetic diversity?

Answer 2

The total number of different alleles in a population.

• the greater the number of alleles in a species, the greater the genetic diversity
• this is because there are a wider variety of characteristics, so some individuals will be suited to withstand environmental change
• genetic diversity allows natural selection to occur.

Question 3

What is a population?

Answer 3

A groups of individuals of the same species who live in the same place and can interbreed.

Question 4

How does reproductive success affect allele frequency?

Answer 4

• not all alleles are equally likely to be passed on to the next generation because only certain individuals are reproductively successful and pass theirs on.
• this will affect the allele frequency in the entire population

Question 5

How does is the frequency of alleles in a population determined?

Answer 5

• in a population there is a gene pool containing a variety of alleles
• random mutations may result in a new (generally harmful) allele.
• in certain environments the new allele may give an individual an advantage over others in the population.
• these will be better adapted and and more likely to survive competition
• they are more likely to obtain resources to grow rapidly and live longer, giving more time to breed and produce more offspring
• only successful breeders pass on their alleles
• the allele that gave the parents the advantage is likely to be passed on.
• the offspring are more likely to survive and breed successfully
• over many generations the number of individuals with the advantageous allele will increase at the expense of those without it
• over time, the frequency of the advantageous allele increases and the disadvantageous allele frequency decreases.