Natural Asymmetries

When imbalances gain the upper hand

I have written about symmetry once and had pointed out that many animals (and humans) apparently exhibit an innate preference for symmetric over asymmetric patterns. And yet, if we examine Nature and her organisms more closely we find numerous examples of asymmetries. It starts already with the “Big Bang” and the atomic organization of matter and antimatter; you’ll find it with L (left) and D (right) forms of polarized light rotating sugars like glucose (the latter chirality very common, the former very rare). And you’d wonder why cells use only the L-forms of amino acids to build left-handed proteins, when the D-form is nothing but the right-handed mirror image of the L form. But we can move on to whole organisms and although most are at least outwardly symmetric, internal organs (as a look into the human body confirms) are frequently not. —>


Beauty and the Beast

When plants are not what they seem to be

While animals often have good reason to conceal themselves by assuming the colour and shape of the surrounding vegetation, in other words resembling plants, the opposite, namely plants resembling animals is much rarer. There are, however, some plants that are animal-like. Firstly, there are those which possess physiological or functional similarities to animals – and I am not talking here about fungi, mushrooms, yeasts and toadstools, which are not considered to be plants, but comprise a kingdom all by themselves. After all, they do not possess chlorophyll and cannot photosynthesize like plants, but they also do nit move around or reproduce like animals. Yet, they grow (or better “feed”) on organic matter just like animals, possess chitin like insects, and in some cases even possess the enzyme collagenase to digest collagen like animals. But, let’s turn to real plants resembling animals.

There are the sensitive plants like the mimosa, which move and react to touch and heat with a behaviour of some rapid folding and lowering of their leaves, a reaction that is even conducted along the stem to more distant parts of the plant. We can also think of certain fruits that will explode, spring open upon at the slightest touch to cast out their seeds and we must not forget the carnivorous plants, many of which like the famed Venus Fly Trap possess modified rapidly-closing leafy traps with serrated edges or, like the submersed pond bladderwort, operating with a suction device to pull in its prey. Others work with enticing drops of glittering glue ad tiny mobile “tentacles” on the surface of their leaves like the sundews or they developed pitfalls with slippery walls like the pitcher plants – all in order to boost nutrient intake with tissue from small animals, which these plants catch and are able to digest. In fact, the first scientific film I made when I worked for a year with the education channel of a TV company many years ago in Germany, had the title “Pflanzen, die von Tieren leben” (plants that prey on animals). That film also featured the small and endangered underwater version of the Venus Flytrap, known as Aldrovanda vesiculosa.

The most amazing animal-alike plants, however, are found in the second category: they don’t move, trap or digest animals, but they look like some. I am talking here not of cacti or the fruits of a chestnut tree, which resemble sea-urchins or miniature hedgehogs, but of the flowers of various orchids, which look remarkably similar to female wasps, bees, or beetles – depending on the species of orchid. These orchid flowers “mimic” the appropriate female insect to such an extent in shape, size, colour, and even scent that male insects are persuaded to attempt copulating with these dummy females of plant origin. By the time the fooled males have noticed their mistake, they have picked up some orchid’s pollen or left some from a previous encounter and, thus, help pollinating these “tricky” flowers, the “sirens” of the plant world. “Et Dieu… créa la femme”: appropriate not only in the human context.

Explosive plants animals biology bootanic

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© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2016.
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