• Question: How do organisms evolve?

    Asked by ashleighlou to Betul, Bridget, Ceri-Wyn, Maria on 25 Jun 2010 in Categories: .
    • Photo: Bridget Waller

      Bridget Waller answered on 24 Jun 2010:

      This is the big question! Species evolve when three conditions are met.

      1. Inheritance. Animals pass characteristics to their offspring.
      2. Competition. There are more offspring than can survive.
      3. Variation. Offspring have differences, and some are going to be more successful than others.

      If all 2 conditions are met, each generation will change slightly, and species will evolve! This was all Darwin’s idea of course…nothing to do with me.

      ps I used the same answer for a similar question – just to let you know! 🙂

    • Photo: Ceri-Wyn Thomas

      Ceri-Wyn Thomas answered on 25 Jun 2010:

      Firstly, our genes can experience chance mutations which alter the blueprints that instruct our bodies how to grow and develop into adulthood
      These mutations can then be passed from parents to offspring and enter the gene pool. If these mutations cause an organisms to be better adapted for their
      current environment then the organisms will be able to reproduce more successfully before they die. If an adaptation puts an organism at a disadvantage (prom prey or other environmental factors) then that organism may die before
      it had the chance to reproduce. This is known as “survival of the fittest” and it’s how natural selection works!
      If a species becomes isolated from the rest of its group (by a mountain chain forming, or through habitat loss for example) any mutations that occur and are retained in the isolated population
      will not enter the rest of the population through sexual reproduction- this is often how speciation occurs! So new species with different adaptations arsing from mutations can form over time.
      The biodiversity we see today, having stemmed from single-celled organisms has arisen through small incremental steps like I’ve described over about 2-3 billion years! It’s not hard to imagine
      when you take those sorts of tim eframes into account!