Reproduction

• Sexual reproduction involves the joining (fusion) of male and female gametes
• Sperm and egg cells are gametes in animals
• Pollen and egg cells are gametes in flowering plants
• In sexual reproduction there is mixing of genetic information which leads to variety in the offspring
• Asexual reproduction involves only one parent and no fusion of gametes
• In asexual reproduction there is no mixing of genetic information which leads to genetically identical offspring (clones)
• Asexual reproduction only involves mitosis
• Advantages of sexual reproduction:

  • Produces variation in the offspring
  • If the environment changes variation gives a survival advantage by natural selection
  • Natural selection can be speeded up by humans in selective breeding to increase food production
• Advantages of asexual reproduction

  • Only one parent needed
  • More time and energy efficient as do not need to find a mate
  • Faster than sexual reproduction
  • Many identical offspring can be produced when conditions are favourable
• Malarial parasites reproduce asexually in the human host, but sexually in the mosquito
• Many fungi reproduce asexually by spores but also reproduce sexually to give variation
• Many plants produce seeds sexually, but also reproduce asexually by runners such as strawberry plants, or bulb division such as daffodils