Asexual & Sexual Reproduction

  • Created by: heyitsjen
  • Created on: 30-11-18 14:04
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  • Sexual Reproduction
    • It happens when a male gamete (sperm) and a female gamete (egg) join. The fusion of gametes is called fertilisation.
      • Fertilisation combines mum and dad's DNA and forms an offspring that's like them but not identical.
      • In animals it's done with egg and sperm, in plants it's pollen and eggs
      • Pros of sexual reproduction: creates variation and species can addapt. It means a disease could only effect few.
        • Cons of sexual reproduction: it takes time and energy to be done effectively e.g. planning out your cycle
    • Asexual Reproduction
      • Only has one parent, whose offsprings are genetically identical. Sometimes, plants undergo asexual reproduction and make exact clones.
      • Types of Reproduction
      • Ways of artificially cloning a plant: growing a new part from a section of a stem, or growing plantlets from small amounts of a tissue
        • How to take plant cuttings to make plant clones: find 10-20cm section of plant stem. Cut the plant stem just under a node - point leaves grow from. Trim off the bottom leaves. Put some soil in a cup and make a small hole in it. Dip your plants base in rooting powder and put it into the soil and firm soil around the stem. Cover plant pot to protect the new stem so it grows as a clone.
        • Propogating tissue cultures: tissue scraped from parent plant. Tissue samples are placed in agar growth medium containing nutrients and plant hormones. The samples develop into plantlets. Plantlets go into compost and grow as a clone of the original plant. It is done in a sterile environment - good because less diseases.
      • Parent cells divides to make exact copies (genetically identical) or plants do it by bulb cuttings etc.
      • Pros are: it is done quickly and causes a larger population, and all clones have the same strenghts. However there is no variation and any disease could affect every offspring.
    • Types of Reproduction

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