Mutations & Gene Pools Practice Questions Flashcards Preview

Human Biology Unit 4 > Mutations & Gene Pools Practice Questions > Flashcards

Flashcards in Mutations & Gene Pools Practice Questions Deck (6)
Loading flashcards...
1
Q

How does natural selection contribute to a difference in allele frequency? (4 marks)

A
  • mutations cause variation within the gene pool
  • different selection pressures on gene pools exist
  • a different allele is favoured over the other
  • this allele increases in frequency
2
Q

How does genetic drift differ from natural selection? (2 marks)

A
  • chance occurrence
  • more likely in small populations
  • no selection pressures
3
Q

What three features are required for natural selection to occur in a population? (3 marks)

A
  • variation
  • selective pressures
  • reproduction, high birth rate
4
Q

What is meant by a selectively advantageous mutation?

A
  • organisms with mutated gene more likely to survive
  • mutated gene provides an advantage over normal one
  • individuals with the mutated gene are more likely to reproduce
5
Q

Describe how the link between the sickle cell allele and malaria can lead to changes in the allele frequencies in a population. (4 marks)

A
  • malaria reduces the life expectancy and reproductive potential of an individual
  • the sickle cell gene is favoured in malarial prone areas
  • those with the trait are more likely to survive and reproduce
  • therefore the gene frequency increases
6
Q

How does a gene mutation differ from a chromosomal mutation? (2 marks)

A
  • a gene mutation only affects a single gene, not multiple

- a gene mutation may affect a protein produced