Variation through meiosis

Question 1

sources of variation

Answer 1

• mutations
• crossing over
• independent assortment
• sexual reproduction

Question 2

describe crossing over

Answer 2

During prophase homologous chromosomes pair up to form a tetrad. Protein strings align the strands together and form connections called chiasmata. At the chiasma exchange of genetic material between homologous chromatids can occur. Exchange of genes between maternal and paternal chromosomes creates a new gene combination which increases variation.

Question 3

What is the law of independent assortment

Answer 3

The law of independent assortment refers to the random orientation of maternal and paternal homologous chromosomes at the equator during meiosis metaphase one. The orientation of one pair is unaffected by the orientation of others.

Question 4

describe sexual reproduction

Answer 4

Fertilisation is the fusion of two gametes. Sexual reproduction gives rise to an individual with a combination of two individuals’ genes.