You will have learned all about shapes and symmetry in your Maths lessons. But, have you ever thought about symmetry in animals?
Most animals display some sort of symmetry. This is necessary in order to ensure that bodily proportions are balanced, and they don’t topple over! By arranging body parts, and sense organs in this way, it means animals are able to react to stimuli from all around them. There are a number of different types of symmetry in animals, including bilateral, radial and spherical.
Spherical symmetry is quite rare, and is usually found in protozoa. Their bodies are sphere-shaped, with all the parts radiating from the centre of the sphere. Sea animals such as jellyfish, sea stars, sea anemones and urchins show radial symmetry. Radial symmetry looks like a pie cut into identical pieces. Rather like rays on a sun, the body parts are arranged around a central point. It helps these animals, as they move very slowly, to detect environmental changes equally from all directions.
In fact, most animals, including invertebrates and vertebrates display bilateral symmetry. Probably the most obvious example of this particular symmetry is the butterfly. Whenever bilateral symmetry occurs, if you cut the organism down the middle then it will look the same on both sides.
Our “How to work with…” guide this week is all about shapes. If you need to know what a parallelogram or trapezium is, or how to tell the difference between an isosceles and scalene triangle – this is the guide for you. It describes the properties of regular 2D shapes, including lines of symmetry and rotational symmetry. Try some questions, and use the answers to check your understanding.
Click on the picture below to see the guide.
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