• Question: Why do some creatures have a backbone and why do some not?

    Asked by anon-357641 on 15 Mar 2023.
    • Photo: Sam Mugford

      Sam Mugford answered on 15 Mar 2023:

      different branches of life came up with different ways to solve the same problem. In this case how do you hold together a soft floppy body made of muscle and other organs? Vertebrates evolved a system of internal bones- a skeleton- to provide structure and rigidity, whereas invertebrates -like insects- instead evolved an external skeleton (an exoskeleton).

      the exoskeleton has advantages and disadvatages compared to the endoskeleton like ours. the exoskeleton also acts like a suit of armour and protects insects against damage. However having an exoskeleton becomes very difficult for large animals becusae it would have to be very heavy. That’s why insects cant grow bigger than about 20 or 30cm, any bigger than that and they would be too heavy to walk or fly. so all the biggest animals in the world have endoskeletons.

    • Photo: Martin Vickers

      Martin Vickers answered on 16 Mar 2023:

      I feel that this is the start of a joke 🙂 I can’t add anything more directly than @Sam’s amazing answer. One thing that you might be interested in if you’re interested in evolution and skeletal development would be palaeontology, studying dinosaurs. With advances in technology we are learning more and more about these fascinating creatures and how life on Earth has evolved.

      On a side note about dinosaurs and bones, if you ever see the movie Jurassic Park, the original one, you’ll notice that the T-Rex walks upright. This is because at the time this is how scientists thought that they walked, and the movie was animated by artists and moviemakers based upon this information.

      However during the development of a later documentary called “Walking with Dinosaurs”, researchers made a 3D model of the T-Rex at the Natural History Museum and put it into a computer model with real physics. They found that it couldn’t walk properly and it actually walked horizontally using the tail as a counter balance.

      These are the kinds of discoveries that scientists make over time, with different technologies, researchers from other disciplines applying their skills and building upon past knowledge.

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