Reproduction

  • Created by: Abc312
  • Created on: 24-04-18 16:21
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  • Reproduction
    • Sexual reproduction
      • Requires genetic information from a mother and father organism
        • This creates offspring that are genetically different to the parents.
      • The mother and father produce gametes in meiosis
        • This makes the egg and sperm cells in animals
          • Each gamete contains half the number of chromosomes than of a normal cell.
        • The gametes in plants are eggs but their sperm in known as pollen.
      • The gametes produced fuse (fertilisation) to form a cell with the full number of chromosomes
        • The offspring inherits features from both parents.
          • This is what  causes variation.
      • Advantages
        • It produces variation in the offspring.
        • Variation increases the chance of surviving a change in the environment
        • Humans can speed up natural selection using selective breeding.
          • This can be used for things such as speeding up food production.
    • Asexual reproduction
      • There is only one parent involved.
      • This happens by mitosis.
        • Which means the new cell has exactly the same genetic information.
          • It is called a clone
      • Bacteria, some plants and some animals reproduce asexually.
      • Advantages
        • Only needs one parent
        • It is more time and energy efficient
          • Organisms don't need to find a mate.
        • It is faster than sexual reproduction
        • Many identical offspring can be produced in favourable conditions.
    • Organisms that reproduce by both methods
      • Malaria
        • It is carried by mosquitoes and when it bites a human the parasite can be transferred.
        • The malaria parasite reproduces sexually when it is in the mosquito
        • The malaria parasite reproduces asexually in the human host.
      • Fungi
        • Fungi produce spores which can become new spores when they land in a suitable place.
          • They can be produced sexually
            • This creates variation in the fungi so often happens in response to an unfavourable change in the environment.
          • They can be produced asexually.
            • This creates fungi that are identical to the parent.
      • Plants
        • Most plants make seeds sexually but some do it asexually.
        • Strawberry plants produce runners.
          • These are horizontal stems that grow on the surface of the soil away from the plant.
            • At points along the runner a new strawberry plant forms.
              • The strawberry plant is identical to the original.
        • Plant bulbs can divide to form new bulbs.
          • These new bulbs can grow into a new plant.

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