1. Reproduction

What you need to know...
  • What is sexual and asexual reproduction?
  • Why are they important for the survival of species?
Reproduction is vital to the success of a species. For a species to survive it must be able to produce more offspring than it loses though old age, disease, and predation. Living things can reproduce in different ways – asexual reproduction and sexual reproduction.

Asexual Reproduction
A bacterium reproduces by asexual reproduction. When a bacterium reproduces it simply copies its DNA and then divides in half - we call this process cell division. This means in asexual reproduction there is only one parent and all the offspring are identical to that parent. 

The diagram below shows asexual reproduction in bacteria. One bacterium divides to form two, which both divide to form four which each divide again to form eight bacteria. Asexual reproduction can grow populations very quickly.

Yeast also reproduce by asexual reproduction. You can see yeast reproducing below by forming “buds”. These buds will eventually form separate but identical cells.

Plants can reproduce by asexual reproduction too. They do this by producing structures such as bulbs, plantlets and tubers. You will learn more about this in the Propagating and Growing Plants section. 

Sexual Reproduction

Most animals and flowering plants reproduce by what we call sexual reproduction. In sexual reproduction, there are two parents and all the offspring are different from each other. The parents produce sex cells which combine to form a fertilised egg (in animals) or a seed (in plants). The DNA in the offspring is a mixture of both parents
Sexual reproduction is very important because it creates variation in the offspring. Variation is important because it create individuals with new combination of genes. These combinations of genes may give the individuals useful characteristics such as resistance to disease, tolerance to drought and other useful characteristics. The more variation there is in a population the more likely it is to be able to be able to survive changes in the environment.