6.6 Sexual & Asexual reproduction

Plants can reproduce both sexually & asexually

Animals reproduce sexually

Bacteria reproduce asexually

Sexual

• fusion of male & female gametes (fertilisation)

• Offspring contain mixture of parent genes - genetically different

Asexual

• one parent

• No gametes involved

• No mixing of genetic material

  • so no genetic variation

• All offspring are genetically identical

• For eukaryotic organisms, asexual reproduction is achieved through mitosis

• For prokaryotic organisms, asexual reproduction is achieved through binary fission

Pros & cons

Sexual reproduction

• Lots of genetic variation within population

  • less likely to get wiped out by a single event (like a disease)

    • some individuals will be more resistant to it than others

  • population can adapt to changing conditions

    • allows evolution to take place

• takes a lot more time & energy to reproduce

Asexual reproduction

• One parent is needed

• Process is quick

  • allows single organism to quickly colonise a new area

• No genetic variation (all offspring are clones)

  • if new disease comes along & one of the offspring is susceptible to it, all the other offspring will be too

    • so could possibly wipe out entire population

  • less chance of adapting to new conditions