Sexual & Asexual Reproduction: Differences (Edexcel IGCSE Biology)

• Sexual reproduction is:

The process involving the fusion of the nuclei of two gametes to form a zygote (fertilised egg cell) and the production of offspring that are genetically different from each other

• Two parent organisms are required for sexual reproduction
• The gametes are produced through meiosis
• After fertilisation, the offspring develops through mitotic cell divisions
• Offspring produced by sexual reproduction are genetically different to the parent organisms
  • They share half of the DNA from each parent
• Sexual reproduction is a relatively slow reproduction process
• Variation introduced into populations as a result of sexual reproduction, provides a survival advantage to the population

• Asexual reproduction is:

The process resulting in genetically identical offspring being produced from one parent

• Asexual reproduction does not involve gametes or fertilisation
• Only one parent is required so there is no fusion of gametes and no mixing of genetic information
• As a result, the offspring are genetically identical to the parent and to each other (they are clones)
• The process occurs much more quickly and efficiently than sexual reproduction which can provide a survival advantage to populations
• However, lack of genetic variation means that populations are more vulnerable to disease or environmental change
• Many plants reproduce via asexual reproduction
• Bacteria produce exact genetic copies of themselves in a type of asexual reproduction called binary fission

Bacteria produce exact genetic copies of themselves in a type of asexual reproduction called binary fission

• The key differences between sexual and asexual reproduction are compared in this table below: