We see it all the time but most of the time don’t even realise it.
Bilateral Symmetry in Nature.
Most easily understood as Reflective Symmetry.
Not to be confused with Rotational symmetry, Bilateral or Reflective symmetry is when the mirrored elements are arranged around a centre line.
Idea 52 from 60 Wild ideas for Summer Holidays, Can you find any bilateral symmetry on the beach?.
Interestingly the most common form of symmetry in humans is bilateral. Well at least that on the outside. internal organs are not mirrored.
anyway back to the beach.
Bilateral symmetry can be easily found on shells if you are lucky enough to find any type of clam style shell that is still attached to its other half.
These are often referred to as ‘Bi-Valve’; having two halves.
Many leaves will show a tendency towards bilateral symmetry because of the presence of a mid vein. If you have any Begonia plants you will notice these aren’t bilaterally symmetrical but asymmetrical. If you look closely you may notice that it will have a partner leaf on the other side of the stem that will appear to be a mirror image of it, so bilateral symmetry exists in a larger form, using the stem of the plant as the centre line.
Of course with any natural forms , at some point the dynamic that governs the developing form has come into contact with physical matter (in the environment) and this can have an impact on any irregularities but with many forms it is easy to see that the intention towards a bilateral symmetry is there.
With flowers, what immediately springs to mind is the rotational symmetry of daisies or similar. Yet many of the pea family or orchids display bilateral symmetries.
Most creatures that move of their own accord will display not just reflective symmetry along a centre line but also display similarities along between the front and back sections. This can be called ‘Dorsiventrality’ and is a law not just connected to creatures but to many moving manmade objects too.
but for now , lets just focus on reflective and bilateral as they are easy to replicate and see around us without getting too technical.
This is a resource post for 60 Wild ideas for the Summer holidays. A summer activity download for 6-11 year olds. To download your free copy click here.
