This month's "theme" is Patterns in Nature: interesting shapes or colours found in nature. I have chosen an extraordinary eucalyptus tree, zebras, a puzzling butterfly, and some neat-looking microorganisms. Although there are many more examples, - especially in the case of flowers - the four seen in the photo are my favourite. :)
The bark of the rainbow eucalyptus tree is one of the most extraordinary patterns in nature. It looks as though someone took a brush and painted the tree; however, this is not the cause of this spectacular coloration.
The bark consists of a variety of colourful hues, and if you look closely at it, it is peeling. It is this peeling, that is responsible for the multicoloured bark.
Fine layers of bark peel in strips of varying shape and size, revealing a smooth, white to pale green surface, which with age turns to vibrant green, grey, pink, red, orange, blue, and purple. The colour change is induced by the sun, which influences the bark's pigment centres. (The process is analogous to leaves changing colour in Fall, or tanning hides).
This is the only species of eucalyptus to be found in the Northern Hemisphere, and the more tropical the habitat, the more pronounced the "rainbow effect" becomes! (more sun yields more pigment alteration).
There are three species of Zebras, and all of them are bizarrely striped. Like the fingerprints of humans, the striping pattern of any individual zebra is unique from any other. The stripes of zebras have always been an interesting puzzle to scientists - but what purpose do they serve?
If you've ever rode a horse, or even near one, you probably noticed flies swarming all over it. Flies can often carry diseases, and when bitten, the victim can contract that disease. Recent research suggests that the stripes of a zebra are used to ward off disease bearing horseflies (seen on the right). But how?
Well, although insect eyes are really neat to look at, they aren't the best eyes in the animal kingdom. The design of their compound eyes has a major defect: the arrangement of the lenses causes the image to appear in segments (it isn't one whole image like what we see, it's more like looking through a net). As a result, flies often have difficulties interpreting light - and the stripes of a zebra make it even tougher (the white on a zebra is not reflected by polarized light the same way as brown or black (which are reflected). The stripes basically confuse the fly. Although this has all been supported quantitatively through experiments, the impact the stripes have on the fly is still a bit cloudy.
Zebras could use their stripes as camouflage in the right terrain, like tigers do when hunting (stripes help to break up the shape of the animal, making it much more difficult to detect). In addition, since every zebra will have a different pattern, scientists suggest that they can be used for recognizing family members. The stripes are also suggested to affect the depth perception of predators, ultimately making them harder to catch.
The eighty-eight and eight-nine butterflies exhibit one of the most bizarre patterns in nature, and one of the most puzzling to scientists. There are different species, which may have different colours, or different concentric markings (which produce the "numbers"). But why have such an odd marking?
Adaptations are well studied in ecology, and are typically only long-lived if there is some sort of benefit to the organism (whether direct or indirect). It is unclear what these bizarre markings are for, but our best guess, for now, is that they are involved in the social ecology of the organism. (It may be used as a mating display, a way to recognize family, and so on).
A unique characteristic that some of these butterflies possess, is the ability to hear. They have what is known as a Vogel’s organ, a tympanal based auditory instrument (i.e. similar to an ear), that is located at the base of the forewing. An odd place for an "ear", nonetheless!
The bark consists of a variety of colourful hues, and if you look closely at it, it is peeling. It is this peeling, that is responsible for the multicoloured bark.
Fine layers of bark peel in strips of varying shape and size, revealing a smooth, white to pale green surface, which with age turns to vibrant green, grey, pink, red, orange, blue, and purple. The colour change is induced by the sun, which influences the bark's pigment centres. (The process is analogous to leaves changing colour in Fall, or tanning hides).
This is the only species of eucalyptus to be found in the Northern Hemisphere, and the more tropical the habitat, the more pronounced the "rainbow effect" becomes! (more sun yields more pigment alteration).
There are three species of Zebras, and all of them are bizarrely striped. Like the fingerprints of humans, the striping pattern of any individual zebra is unique from any other. The stripes of zebras have always been an interesting puzzle to scientists - but what purpose do they serve?
If you've ever rode a horse, or even near one, you probably noticed flies swarming all over it. Flies can often carry diseases, and when bitten, the victim can contract that disease. Recent research suggests that the stripes of a zebra are used to ward off disease bearing horseflies (seen on the right). But how?
Well, although insect eyes are really neat to look at, they aren't the best eyes in the animal kingdom. The design of their compound eyes has a major defect: the arrangement of the lenses causes the image to appear in segments (it isn't one whole image like what we see, it's more like looking through a net). As a result, flies often have difficulties interpreting light - and the stripes of a zebra make it even tougher (the white on a zebra is not reflected by polarized light the same way as brown or black (which are reflected). The stripes basically confuse the fly. Although this has all been supported quantitatively through experiments, the impact the stripes have on the fly is still a bit cloudy.
Zebras could use their stripes as camouflage in the right terrain, like tigers do when hunting (stripes help to break up the shape of the animal, making it much more difficult to detect). In addition, since every zebra will have a different pattern, scientists suggest that they can be used for recognizing family members. The stripes are also suggested to affect the depth perception of predators, ultimately making them harder to catch.
Adaptations are well studied in ecology, and are typically only long-lived if there is some sort of benefit to the organism (whether direct or indirect). It is unclear what these bizarre markings are for, but our best guess, for now, is that they are involved in the social ecology of the organism. (It may be used as a mating display, a way to recognize family, and so on).
A unique characteristic that some of these butterflies possess, is the ability to hear. They have what is known as a Vogel’s organ, a tympanal based auditory instrument (i.e. similar to an ear), that is located at the base of the forewing. An odd place for an "ear", nonetheless!
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