The color of the beast is the general appearance of the animal resulting from the reflection or jet of light from its surface. Some animals are brightly colored, while others are hard to see. In some species, such as peacocks, males have strong patterns, striking and colorful colors, while females are much more invisible.
There are several different reasons why animals evolve color. Camouflage allows animals to stay hidden from view. Animals use colors to advertise services such as cleaning animals from other species; to signal their sexual status to other members of the same species; and in mimicry, taking advantage of other species' warning colors. Some animals use flashes of color to divert attacks by startling predators. Zebras can use dazzling movements, confusing predatory attacks by moving bold patterns quickly. Some animals are colored for physical protection, with pigments in the skin to protect from sunburn, while some frogs can brighten or darken their skin for temperature regulation. Finally, animals can be colored by chance. For example, blood is red because of the hem pigment needed to carry red oxygen. Animals that are colored in this way can have a striking natural pattern.
Animals produce colors in different ways. Pigments are particles of colored material. Chromatophores are cells that contain pigment. The distribution of pigment particles in chromatophore may change under hormonal or neuronal control. For fish it has been shown that chromatophores can respond directly to environmental stimuli such as visible light, UV radiation, temperature, pH, chemicals, etc., Color change helps individuals become more or less visible and important in agonistic displays and in camouflage. Some animals, including many butterflies and birds, have microscopic structures in scale, feathers or feathers that give them brilliant color. Other animals including squid and some deep sea fish can produce light, sometimes from different colors. Animals often use two or more of these mechanisms together to produce the colors and effects they need.
Video Animal coloration
History
Animal coloration has been an interesting topic and research in biology for centuries. In the classical era, Aristotle notes that the octopus was able to change its color to fit its background, and when it was feared.
In his book 1665 Micrographia , Robert Hooke describes the color â € Å"fantasticâ € (structurally, not the pigment) of the Peacock feather:
Parts of the Feather This glorious bird appears, through the Microscope, no less conspicuously then do all the Feathers; because, as the naked eye 'tis proved that the rod or quill of each Feather on the tail sends a multitude of Lateral branches,... so that each thread in the Microscope appears a large long body, consisting of many parts that reflect brightly ... their upper side for me is made up of many thin, very thin bodies, and lies very close together, and thus, like a mother of pearls, does not fully reflect light very quickly, but the tinge of light is in the most outlandish way ; and in various positions, with respect to light, they reflect back one color now, then another, and most obviously. Now, that these colors are the only thing that is fantastic, that is, as it appears immediately from the refraction of light, I find with this, that water moistens these colored parts, destroying their color, which seems to be continuing. from reflection and refraction changes.
According to Charles Darwin's natural selection theory in 1859, features such as coloration evolved by providing individual animals with reproductive benefits. For example, individuals with camouflage slightly better than others of the same species, on average will leave more offspring. In the Origin of Species , Darwin writes:
When we see green leaf-eating insects, and striped striped peelers; alpine white ptarmigan in winter, red-grouse heather color, and black peat belimbis, we must believe that these colors are a service for the birds and insects in preserving them from harm. Grouse, if not destroyed in some period of their lives, will increase in countless numbers; they are known to suffer most from birds of prey; and the eagles were guided by sight against their prey, so much so, on parts of the Continent were warned not to keep white doves, as most responsible for destruction. So I can not see any reason to doubt that natural selection may be most effective in providing the right color for each type of grouse, and in maintaining that color, once obtained, true and constant.
1863 Henry Walter Bates' book The Naturalist on the River Amazons describes his extensive research on insects in the Amazon basin, and especially butterflies. He found that seemingly similar butterflies often come from different families, with harmless species mimicking toxic or bitter-tasting species to reduce the likelihood of being attacked by predators, in the process now called after him, Batesian mimicry.
Darwin's highly authorized Edward Bagnall Poulton 1890 The Colors of Animals, its meaning and use, especially those considered in the case of insects, present the case for three widely accepted but controversial or entirely new aspects of animal dyeing at the time that. This strongly supports Darwin's theory of sexual selection, arguing that a clear distinction between male and female birds like the Argus birds is chosen by females, indicating that bright male hairs are found only in "which by the day" species. This book introduces the concept of frequency-dependent selection, such as when mimics are eaten less frequently than unpleasant models whose colors and patterns they copy. In the book, Poulton also coined the term aposematism for warning colors, which he identifies in very different animal groups including mammals (such as skunks), bees and wasps, beetles, and butterflies.
Frank Evers Beddard's 1892 book, Animal Colouration, acknowledges that natural selection exists but examines its application to disguise, imitate, and sexual selection with great criticism. The book was in turn criticized by Poulton.
The 1909 book Abbott Handerson Thayer Hiding-Color in the Animal Kingdom , completed by his son Gerald H. Thayer, argues appropriately for the widespread use of crypsis among animals, and specifically described and described the hoarding for the first time. However, Thayers ruined their case by declaring that camouflage was the sole purpose of animal staining, which led them to claim that even the brilliant pink feather of flamingos or rose spoons was faint - against the pink sky momentarily at dawn or dusk. As a result, the book was ridiculed by critics including Theodore Roosevelt as "pushing [the" doctrine of hiding colors] to a fantastic extreme and incorporating such wild oddities to call for the application of common sense. "
Hugh Bamford Cott's 500-page Coloring Adaptive in Animals book, published in the wartime of 1940, systematically describes the principle of camouflage and mimicry. This book contains hundreds of examples, over a hundred photos and images accurately and artistically Cott himself, and 27 pages of references. Cott is focused primarily on "maximum disturbing contrast", the type of pattern used in military camouflage such as annoying pattern material. Indeed, Cott describes such an application:
the effect of the intruder pattern is to break what is really a continuous surface into what appears to be a number of non-continuous surfaces... as opposed to the body shape in which they are superimposed.
Animal staining provides important early evidence for evolution through natural selection, at a time when little direct evidence is available.
Maps Animal coloration
The reason for evolution for animal staining
Camouflage
One of the pioneers of animal coloring research, Edward Bagnall Poulton classifies shapes of color, in a helpful way. He described: a protective similarity; aggressive resemblance; adventitious protection; and the variable protective resemblance. This is discussed in turn below.
The protective similarity is used by the prey to avoid predation. These include a special protective resemblance, now called mimesis, in which all animals look like other objects, for example when a caterpillar resembles a twig or bird dropping. In general, protective similarities, now called crypsis, animal textures blend into the background, for example when the colors and patterns of moths blend with the bark of a tree.
Aggressive resemblance is used by predators or parasites. In a special aggressive resemblance, the animal looks like something else, enticing prey or host to get closer, for example when a mantis resembles a certain kind of flower, like an orchid. In general, aggressive, predatory or parasitic attachments blend into the background, for example when leopards are hard to see in long grass.
For adventitious protection, animals use materials such as twigs, sand or leather pieces to hide the outline, for example when caddis fly larvae build decorated boxes, or when decorator crabs adorn their backs with seaweed, sponges and stones.
In variable protective similarities, animals such as chameleons, flatfish, squid or octopus change the pattern and color of their skin using special chromatophore cells to resemble whatever background is currently at rest (as well as for signaling).
The main mechanism for creating the similarities described by Poulton - whether in nature or in military applications - is crypsis, blending into the background so that it becomes hard to see (this includes both general and general resemblance); distracting patterns, using colors and patterns to break the outline of animals, which are primarily related to common resemblances; mimesis, resembling other objects that do not attract the attention of the observer, which is associated with a special resemblance; countershading, using graded colors to create the illusion of flatness, which is largely related to general resemblance; and counterillumination, producing light to match the background, especially in some species of squid.
Countershading was first described by the American artist Abbott Handerson Thayer, a pioneer in the theory of animal staining. Thayer observes that when a painter takes a flat canvas and uses colored paint to create the illusion of solidity by painting in the shadows, animals like deer often darken on their backs, become lighter toward the belly, creating (like the observations of Hugh Cott's zoology) , and against a suitable background, from invisibility. Thayer's observation "Animal is painted by Nature, darkest in parts which tend to be the brightest by the light of heaven, and on the contrary " is called Thayer's Law .
Signal
Colors are widely used to signal to diverse animals such as birds and shrimp. Signaling includes at least three goals:
- ads, to signal the ability or service to other animals, whether in a species or not
- sexual selection, in which members of one sex choose to mate with other sex members of the appropriate color, thus encouraging the development of such colors
- warning, to signal that the animal is dangerous, for example, it can be stinging, toxic or bitter. Warning signals can be mimicked honestly or incorrectly.
Ad services
Advertising colors can signal the services that animals offer to other animals. This may be of the same species, as in sexual selection, or of different species, as in symbiotic cleansing. Signals, which often combine color and movement, can be understood by many different species; for example, the banded crayfish clearing station Stenopus hispidus is visited by various species of fish, and even by reptiles such as hawksbill.
Sexual_selection> Sexual election
Darwin observed that males of several species, such as birds of paradise, are very different from females.
Darwin explains the male-female differences in his theory of sexual selection in his book The Descent of Man . After females start selecting males according to certain characteristics, such as long tail or colored emblems, these characteristics are emphasized more in males. Eventually all men will have the characteristics that women sexually choose, because only men can reproduce. This mechanism is powerful enough to create features that are very harmful to men in other ways. For example, some birds of paradise have wingspan or tails that are so long as to block flight, while their brilliant colors can make males more vulnerable to predators. In the extreme, sexual selection can push species into extinction, as has been debated for the big horns of the Irish Irish elk, which may have made it difficult for grown men to move and feed.
Various forms of sexual selection are possible, including competition among men, and the selection of women by men.
Warning
COLOR COLOR (aposematism) is effectively the "opposite" of camouflage, and a special case of advertising. Its function is to make animals, such as wasps or coral snakes, very striking for potential predators, so it is known, remembered, and then avoided. As Peter Forbes observes, "Human warning signs use the same color - red, yellow, black, and white - that nature uses to advertise dangerous creatures." The warning color works by being associated with a potential predator with something that makes the animal color warning unpleasant or dangerous. This can be achieved in several ways, by being a combination of:
- unpleasant, for example caterpillar, cocoon, and adult cinnabar moth, king and variable checkerspot butterflies have bitter-tasting chemicals in their blood. One king contains more than enough toxins like digitalis to kill a cat, while the king's extract makes vomit vomit.
- smells bad, for example skunks can spray fluid with a strong and durable smell
- aggressive and able to defend themselves, for example badger honey.
- poisonous, for example a wasp can give a painful sting, while a snake like a poisonous snake or a coral can cause a fatal bite.
The warning color can work best through innate behavior (instinct) in the predatory part of potential, or through the avoidance learned. Either can cause various forms of mimicry. Experiments show that avoidance is studied in birds, mammals, lizards, and amphibians, but some birds like their great breasts have shied away from certain colors and patterns such as black and yellow stripes.
Mimicry
Mimicry means one species of animal resembling another species is close enough to deceive predators. To evolve, an imitated species must have a warning color, as it appears bitter or dangerous to give natural selection something to do. Once a species has little, possibly, resemblance to a warning colored species, natural selection can push colors and patterns toward more perfect mimicry. There are many possible mechanisms, which are by far the best known:
- Batesian mimicry , in which edible species resemble an unpleasant or dangerous species. This is most common in insects such as butterflies. A well-known example is the harmless hoverflies (which have no sting) in the bees.
- MÃÆ'¼llerian mimicry , in which two or more species of animals are harmful or unlike each other. This is most common among insects such as wasps and bees (hymenoptera).
Batesian mimicry was first described by naturalist pioneer Henry W. Bates. When edible prey animals come to resemble, even slightly, unwelcome animals, natural selection benefits an individual that is even slightly more akin to an unpleasant species. This is because even a small level of protection reduces predation and increases the likelihood that an individual imitate will survive and reproduce. For example, many species of hoverfly are black and yellow like bees, and consequently avoided by birds (and humans).
Mimicry MÃÆ'¼llerian was first described by the naturalist pioneer Fritz MÃÆ'¼ller. When an unpleasant animal comes to resemble a less favored animal, natural selection benefits an individual who is even slightly more like a target. For example, many species of bees and bees that sting are both black and yellow. MÃÆ'¼ller's explanation of the mechanism for this is one of the first mathematical uses in biology. He argues that predators, like young birds, have to attack at least one insect, say a wasp, to know that black and yellow are stinging insects. If the bees are different in color, the young bird must also attack one of them. But when the bees and the wasps look alike, the young bird only needs to attack one of the whole group to learn to avoid them all. So, fewer bees are attacked if they imitate a wasp; the same applies to bees that mimic the bees. The result is a resemblance to mutual protection.
Disorder
Startle
Some animals such as many moths, grasshoppers and grasshoppers, have a repertoire of threatening or shocking behavior, such as suddenly displaying flashy eyespots or bright and contrasting color spots, so scare or momentarily distracts the predator. It gives game animals a chance to escape. This behavior is deimatic (rather surprising) than aposematic because it is suitable for predators, so the color of warning is bluff, not an honest signal.
Motion dazzle
Some prey animals such as zebra are characterized by high contrast patterns that may help confuse their predators, such as lions, during a pursuit. The thick lines of the Zebra herd have been claimed to make it difficult for predators to accurately predict the speed and direction of the prey, or to identify individual animals, providing a better chance of escape. Because dazzling patterns (such as Zebra lines) make animals more difficult to capture while moving, but more easily detected when stationary, there is an evolutionary trade-off between glare and camouflage. Another theory is that zebra lines can provide protection from flies and biting insects.
Physical protection
Many animals have dark pigments such as melanin in the skin, eyes, and fur to protect themselves from sunburn (damage to living tissue caused by ultraviolet light).
Temperature settings
Some frogs like Bokermannohyla alvarengai, who bask in the sun, brighten their skin color when it's hot (and dark when cold), making their skin reflect more heat and avoid overheating.
Incidental color
Some animals are colored purely by chance because their blood contains pigment. For example, amphibians like olm living in caves may be largely colorless because the colors do not have function in that environment, but amphibians show a red color due to the haem pigment in their red blood cells, which is needed to carry oxygen. They also have a little orange riboflavin on their skin. Human albino and people with fair skin have the same color for the same reason.
The mechanism of color production in animals
Animal staining can be the result of a combination of pigments, chromatophores, structural staining and bioluminescence.
Color by pigment
Colored pigments of chemicals (such as melanin) in animal tissues. For example, the Arctic fox has a white coat in winter (contains little pigment), and a brown coat in summer (containing more pigments), eg seasonal camouflage (polyphenme). Many animals, including mammals, birds, and amphibians, can not synthesize most of the pigments that color their feathers or fur, in addition to the brown or black melanin that gives many of their earth tones mammals. For example, the bright yellow of American gold, the shocking orange of the teenage red-spotted lizard, the crimson red from the cardinal and the pink of flamingo are all produced by carotenoid pigments synthesized by plants. In the case of flamingos, birds eat pink shrimp, which also can not synthesize carotenoids. Shrimp get their body color from microscopic red algae, which like most plants are able to make their own pigments, including carotenoids and chlorophyll (green). Animals that eat green plants do not become green, because chlorophyll does not survive from digestion.
Color variables by chromatophores
Chromatophore is a cell containing a special pigment that can resize it, but more often retain its original size but allow the pigment in it to be redistributed, thus varying the color and pattern of the animal. Chromatophore may respond to hormonal and/or neurobal control mechanisms, but the simplest response to visible light stimulation, UV radiation, temperature, pH change, chemicals, etc. has also been documented. Voluntary control of chromatophores is known as metachrosis. For example, squid and chameleon can quickly change their appearance, both for camouflage and for signaling, as Aristotle put it more than 2000 years ago:
Octopus... searches for its prey by changing its color to make it look like the color of the stone adjacent to it; it's also so when worried.
When squid such as squid and squid find themselves with light backgrounds, they contract many of their chromatophores, focusing the pigment into smaller areas, producing dots of small, dense, but much spaced, light-looking patterns. As they enter darker environments, they allow their chromatophores to flourish, create larger black spots, and make their bodies look dark. Amphibians such as frogs have three types of star-shaped chromatophore cells in a separate layer of their skin. The top layer contains 'xanthophores' in orange, red, or yellow; the middle layer contains 'iridophores' with silvery reflection pigments; while the lower layers contain 'melanophores' with dark melanin.
Structural Colors
While many animals can not synthesize carotenoid pigments to create red and yellow surfaces, green and blue colors of bird feathers and insect carapaces are not normally produced by pigment at all, but by structural staining. Structural colors mean the production of colors with microscopically structured surfaces are fine enough to disrupt visible light, sometimes in combination with pigments: for example, peacock peacock feathers are pigmented, but the structure makes them look blue, turquoise and green. Structural colors can produce the most brilliant colors, often colorful. For example, blue/green gloss on bird feathers like ducks, and purple/blue/green/red colors from many beetles and butterflies are created by structural colors. Animals use several methods to produce structural colors, as described in the table.
Bioluminescence
Bioluminescence is the production of light, as by the photophores of marine animals, and the tail of glow-worms and fireflies. Bioluminescence, like other forms of metabolism, releases energy derived from the chemical energy of food. Pigment, luciferin is catalyzed by luciferase enzyme to react with oxygen, releasing light. Jelly combs like Euplokamis are bioluminescent, creating blue and green light, especially when stressed; when disturbed, they remove the luminesces ink in the same color. Because jelly combs are not very sensitive to light, their bioluminescence is unlikely to be used to signal to other members of the same species (eg to attract spouses or expel rivals); more likely, the light helps distract the predator or the parasite. Several species of squid have light-producing organs (photophores) scattered throughout their lower parts that create glittering light. This gives the camouflage light balancing, preventing the animal from appearing as a dark form when viewed from below. Some deep-sea fishermen, which are too dark to hunt for sight, contain symbiotic bacteria in their 'fishing lures' in their 'fishing rod'. It emits light to attract prey.
See also
- Albinism in biology
- Fraud in animals
References
Source
- Cott, Hugh Bamford (1940). Color adaptation in Animals . Methuen, London.
- Forbes, Peter (2009). Deceived and Deceived: Mimicry and Camouflage . Yale, New Haven and London. ISBN: 0300178964
External links
- NatureWorks: Color (for kids and teachers)
- HowStuffWorks: How Animals Camouflage Works
- University of British Columbia: Sexual Selection (lecture for Zoology students)
- Natural Palette: How animals, including humans, produce colors
Source of the article : Wikipedia
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