Symmetry, in biology, the repetition of the parts in an animal or plant in an orderly fashion. Specifically, symmetry refers to a correspondence of body parts, in size, shape, and relative position, on opposite sides of a dividing line or distributed around a central point or axis.

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, Bilateral or Reflective symmetry is when the mirrored elements are arranged around a centre line.Idea 52 from, 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.

The intention for reflective symmetry is there but what happened to the smaller set of legs on the left? Did it loose them and have to regrow?With flowers, what immediately springs to mind is the of daisies or similar.

Yet many of the pea family or orchids display bilateral symmetries. The dashed white line indicates the line of reflectionMost 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.

Not the greatest photo but these snap dragons show reflective symmetry in the flower petalsThis 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.Filed Under:, Tagged With:,.

Symmetry in NatureBy Angel Abney, Andy Tyminski, andPawel NazarewiczMathematics is all around us. As we discover more and moreabout our environment and our surroundings we see that naturecan be described mathematically.

The beauty of a flower, the majestyof a tree, even the rocks upon which we walk can exhibit nature'ssense of symmetry. Although there are other examples to be foundin crystallography or even at a microscopic level of nature, wehave chosen representations within objects in our field of viewthat exhibit many different types of symmetry.This semester in transformational geometry has altered ourviews, or at least our viewfinders. It seems that everywhere welook now our eyes are drawn first to the patterns of symmetrythat exist, and that the object itself is a secondary consideration.So, come join us as we examine examples of bilateral symmetry,radial symmetry, strip patterns and wallpaper patterns in nature.You'll never look at your world the same way again.Beginyour exploration here.Click on any of the topics below to explore howthat symmetry type can be found in nature:       Radial symmetry is rotational symmetry around a fixed pointknown as the center.

Radial symmetry can be classified as eithercyclic or dihedral.Cyclic symmetries are represented with the notation Cn, wheren is the number of rotations. Each rotation will have an angleof 360/n. For example, an object having C3 symmetry would havethree rotations of 120 degrees.Dihedral symmetries differ from cyclic ones in that they havereflection symmetries in addition to rotational symmetry. Dihedralsymmetries are represented with the notation Dn where n representsthe number of rotations, as well as the number of reflectionmirrors present. Each rotation angle will be equal to 360/n degreesand the angle between each mirror will be 180/n degrees. An objectwith D4 symmetry would have four rotations, each of 90 degrees,and four reflection mirrors, with each angle between them being45 degrees.   A starfish providesus with a Dihedral 5 symmetry. Not only do we have five rotationsof 72 degrees each, but we also have five lines of reflection.Another example of astarfish - as we can see, starfish can be embeded in a pentagon,which can then be connected to the Golden Ratio.Also found in the seaare sand dollars.

They too, have D5 symmetry.   Jellyfish have D4 symmetry - four rotations of90 degrees each. It also has four lines of symmetry, and in themiddle you have a four-leafed clover for good luck.Flowers offer a variety of radialsymmetry. Hibiscus - C5 symmetry. The petalsoverlap, so the symmetry might not be readily seen. It will beupon closer examination though.   This hibiscus is slowly wiltingaway, and the C5 symmetry is really evident.After some debate, we decided thatthis flower has C4 symmetry - one row of the petals is underneathanother.Petunias offer some patriotic D5symmetry.Go to the top menu.  Strip pattern symmetry can be classified in seven distinctpatterns. Each pattern contains all or some of the followingtypes of symmetry: Translation symmetry, Horizontalmirror symmetry, Vertical mirror symmetry, Rotationalsymmetry, or Glide reflection symmetry.The seven types are T, TR, TV, TG, TRVG, TGH, and TRGHV.   An Eastern White Pinehas interesting symmetry on it's trunk. Each year, as the treegrows, it develops a new ring of branches (most of which havebeen broken off in the picture above).

The rings move up by similiartranslation vectors, but some variation occurs due to the conditionsfor that year.Another picture of thewhite pine - this time with branches showing. The white pineexhibits T symmetry.Here is a set of animaltracks that exhibits THG symmetry. Because we have a horizontalmirror, we get a glide by default. I think that these are armadillotracks.   Here are some footprints on the beach -in them, we can see a translation and nothing else. That patternis a typical T. I'm not sure how this pattern was accompished,but it looks like whoever did it had two left feet. Here is a set of radioactive footprintscreating a TG pattern.

John Conway simply calls this 'step'.   The copperhead is one of the four poisonous snakes inthe United States. Can you name the other three? Highlight thetext between the arrows for the answer: The Cottonmouth (Water Mocassin),Rattle Snake, Coral Snake elephants), the more likeley it is that it willbe perfectly symmetric.We took two professors, cut and pasted half of their headin Photoshop, and flipped that half horizontally. We then alignedthe two halves so that it came closest ro resembling a humanhead. You be the judge on how good of a job we did and how symmetricpeople around us are in general.   Here is our professor - Dr. ClintMcCrory, who as you will see, is very symmetrical.Which side of Dr.

McCrory do youthink this is.? And this one? How quickly didyou pick up on the differences?   Dr. Larry Hatfield has a part onthe side of his head which makes it easier to notice the symmetryinvolved.Here we can see his right side ofthe face reflected over the middle. And the left side. As you cansee, one is more predominate than the other. What are some thingsthat would contribute to this asymetry?Go to the top menu.Want to learn more?Here are a few links of interest:- Symmetry inand how it effects light.- Our Math 5210/7210page - there are tons of links on that site as well.- If you need any of the terms on this webpage defined, youcan check out- a project that's being worked on here at UGA.

If Intermath doesn'thave what you need, you can always check out. Dragonfly clip art.