Unit 3 — Variation of Traits in Living Organisms

Science — Third Preparatory

1.2 How are traits passed on?

Inherited traits are transferred from parents to children through genes carried by the gametes: the sperm (male gamete) and the ovum or egg (female gamete).
Gametes are produced in the gonads (testes and ovaries) by a type of cell division called meiosis.
Each gamete contains only half of the genetic material, so it carries only one copy of each gene.
At fertilisation, the nucleus of the sperm fuses with the nucleus of the ovum, so the new individual has two copies of every gene: one from the father and one from the mother.

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