Sexual reproduction

Most animals carry out sexual reproduction.

Sexual reproduction involves the joining of two sex cells (gametes) – the sperm (male gamete) and the egg/ovum (female gamete).

The male and female reproductive systems

The male reproductive system makes sperm and delivers it into the female reproductive system.


Sperm are specialised cells highly adapted for their function.

Their adaptations include:

  • A tail – called a flagellum – allowing it to swim through the female reproductive system.
  • A haploid nucleus – containing half the normal number of chromosomes.
  • Many mitochondria to produce energy

The female reproductive system makes and releases eggs/ova. It also protects and nourishes the foetus from fertilisation until birth.