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Evolution Zone

Question: why do worms survive when you chop them in half? x

Asked by alexleigh to Betul, Bridget, Ceri, Laurel, Maria on 21 Jun 2010 in Categories: .

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  • Photo: Laurel FogartyLaurel Fogarty answered on 18 Jun 2010:

    I’m not sure if they do survive, opinion seems to be split on this! one thing is for sure they will live for a couple of hours. This is probably because earth worms are segmented so they have all the apparatus they need to survive in each segment (apart from reproductive organs (which are in a specific body segment) and their superpharangeal ganglia (as scientists have helpfully named their brains) which are in their first segment!)

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  • Photo: Ceri ThomasCeri Thomas answered on 20 Jun 2010:

    It depends on what you mean by ‘worm’ since this applies to many animal groups that have long worm-like bodies. The annelids, nematodes and planaria (flat worms) all have the same body plan. I think if you chopped a common earthworm in half the head end might survive but the tail end wouldn’t. i think most worms prefer to be left whole though ;)

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  • Photo: Bridget WallerBridget Waller answered on 21 Jun 2010:

    Well, if you chop the tail off the worm it can grow a new tail (and won’t die), but it won’t turn into two worms. I remember trying this in the playground at school – seems very cruel now! Worms are important – don’t try it…

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Comments

  • Photo: alexleighalexleigh commented on 23 Jun 2010:

    i havnt tried it or anything by the way so dont worry but i dont get how they have all they need (nearly) in all parts of their body, and would that be the same with a snake? x

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  • Photo: CeriCeri commented on 23 Jun 2010:

    No snakes are a completely different organism- snake organs are stretched throughout their bodies so they would never survive being chopped in half. Most worms have numerous cell clusters scattered throughout their bodies that sort of act like hearts and brains. They respire by taking oxygen in directly through their outermost ‘skin’ so they don’t have lungs like we do which is why they might survive a while after being chopped. Does that help? :)

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