Most fish have highly developed sense organs. Almost all fish during the day have color vision that is at least as good as humans (see vision in fish). Many fish also have chemoreceptors responsible for their extraordinary sense of smell and smell. Although they have ears, many fish may not hear very well. Most fish have sensitive receptors that form a rib-line system, which detects soft currents and vibrations, and feels the movement of nearby fish and prey. Sharks can sense frequencies in the range of 25 to 50 Hz through the ribs.
Fish adjust to using landmarks and can use mental maps based on some landmarks or symbols. Fish behavior in the labyrinth reveals that they have spatial memory and visual discrimination.
Video Sensory systems in fish
Visi
Vision is an important sensory system for most fish species. Fish eyes are similar to terrestrial vertebrates like birds and mammals, but have more rounded lenses. Their retinas generally have stem cells and conical cells (for skotopic and photopic vision), and most species have color vision. Some fish can see ultraviolet and some can see polarized light. Among the jawless fish, lampreys have well-developed eyes, while hagfish only has primitive eyespots. The vision of the fish shows adaptation to their visual environment, for example deep-sea fish have eyes that match the dark environment.
Fish and other aquatic animals live in different light environments from terrestrial species. Water absorbs light so that with increasing depth the amount of available light decreases rapidly. The optical properties of water also cause different wavelengths of light absorbed to different levels, eg long wavelength light (eg red, orange) is absorbed quite quickly compared to short wavelength light (blue, purple), though ultraviolet light (even more wavelength short of blue) is absorbed fairly quickly too. In addition to this universal water quality, various bodies of water can absorb light from different wavelengths due to salt and other chemicals in the water.
Maps Sensory systems in fish
Hearing
Hearing is an important sensory system for most species of fish. The auditory threshold and the ability to localize the sound source are reduced underwater, where the speed of sound is faster than in the air. Underwater hearing is done by bone conduction, and the localization of sound seems to depend on the difference in amplitude detected by bone conduction. Aquatic animals such as fish, however, have more specialized specialized hearing aids under water.
Fish can sense sound through their lateral lines and otolith (ears). Some fish, such as some goldfish and herring species, hear through their swimming sacs, which function more like hearing aids.
Hearing develops well in goldfish, which has Weberian organs, three special vertebral processes that transfer vibrations in the bladder to swim to the inner ear.
Although it is difficult to test the hearing of sharks, they may have sharp hearing and may be able to hear prey for miles and miles. Small opening on each side of their head (not spiracle) leads directly to the inner ear through a thin channel. The ribs show the same arrangement, and are open to the environment through a series of openings called rib pores. This is a general reminder of the origin of two vibration and noise detecting organs grouped together as an acoustico-lateral system. In bony fish and external opening tetrapod to the inner ear has been lost.
Current detection
Hair cells in fish are used to detect movement of water around their body. These hair cells are embedded in a bulge like a jelly called a cupula. Therefore hair cells can not be seen and do not appear on the surface of the skin.
The ribs on fish and amphibian aquatic forms are water-flow detection systems, which consist mostly of vortices. Rib lines are also sensitive to low-frequency vibrations. The mechanoreceptors are hair cells, the same mechanoreceptors for the senses of vestibular and hearing. It is used primarily for navigation, hunting, and schooling. The electric taste receptors are hair cells modified from the ribcage system.
Fish and some water amphibians detect hydrodynamic stimulation through side lines. This system consists of a series of sensors called neuromasts along the body of the fish. Neuromast may be free-standing (superficial neuromasts) or in fluid-filled channels (canal neuromas). Sensory cells in neuromasts are polarized hair cells contained in gelatin cupulas. Cupula, and stereocilia in it, moved by a certain amount depending on the movement of water around it. Afferent nerve fibers are attracted or obstructed depending on whether the hair cells arising from them are deflected in the preferred or opposite direction. Lateral line receptors form a somatotopic map in the brain that informs the fish of amplitude and direction of flow at different points along the body. These maps are located in the medial octavolateral nucleus (MON) of the medulla and in the higher regions such as the semicircularis torus.
Pressure detection
Detection of pressure using Weber's organs, a system consisting of three vertebral appendages transferring the bladder form of gas to the middle ear. This can be used to adjust the fish's buoyancy. Fish like weather fish and other loaches are also known to respond to low-pressure areas but they do not have a swim bladder.
Chemoreception
The aquatic equivalent of the smell in the air feels in water. Many larger catfish have chemoreseptor all over their body, meaning they "feel" whatever they touch and "kiss" any chemicals in the water. "In catfish, juice plays a major role in the orientation and location of food".
Salmon has a strong sense of smell. Speculation about whether the odor gives a hint to the house, back to the 19th century. In 1951, Hasler hypothesized that, once around the estuary or entrance to the river of his birth, salmon could use chemical signals they could smell, and unique to their birth flows, as a mechanism for returning to the river entrance. By 1978, Hasler and his students had convincingly demonstrated that the way salmon found their home rivers with proper accuracy was because they were able to recognize their distinctive smell. They further pointed out that their river odor was imprinted in salmon when they turned into ash, just before they migrated into the ocean. Salmon homecoming can also recognize a distinctive odor in the river as they rise into the main river. They may also be sensitive to the characteristic pheromones released by children. There is evidence that they can "distinguish between two populations of their own species".
Sharks have a keen sense of smell, located in short (united, unlike bone fish) channels between the anterior and posterior nostrils, with some species capable of detecting at least one part per million of blood in seawater. The shark has the ability to determine the direction of the scent given based on the time of aroma detection in each nostril. This is similar to the mammal method used to determine the direction of sound. They are more interested in the chemicals found in the intestines of many species, and as a result often linger near or at waste disposal. Some species, such as nurse sharks, have external spines that greatly increase their ability to feel prey.
The MHC gene is a group of genes that exist in many animals and is important for the immune system; in general, the offspring of parents with different MHC genes have a stronger immune system. Fish are able to smell some aspects of the MHC gene from potential sex partners and prefer to partner with different MHC genes from their own genes.
Electroreception and magnetoreception
Electroreception, or electroception, is the ability to detect electric or current fields. Some fish, such as catfish and sharks, have organs that detect weak electrical potentials on the order of milivolts. Other fish, such as South American electric fish, Gymnotiformes, can produce weak electrical currents, which they use in navigation and social communication. On the shark, Lorenzini's ampullae is an electoreceptor organ. The numbers are hundreds to thousands. The shark uses the Lorenzini ampullae to detect the electromagnetic fields generated by all living things. It helps sharks (especially hammerhead sharks) find their prey. Sharks have the greatest electrical sensitivity in any animal. The sharks find prey hidden in the sand by detecting the electric fields they produce. Ocean currents moving in the Earth's magnetic field also produce electric fields that sharks can use for orientation and navigation possibilities.
The sensing of electric field distance is used by electric catfish to navigate through muddy waters. This fish utilizes spectral change and amplitude modulation to determine factors such as shape, size, distance, velocity, and conductivity. The ability of the electric fish to communicate and identify the gender, age, and hierarchy within the species is also possible through the electric field. EF gradients as low as 5nV/cm can be found in some weak electric water fish.
The paddlefish (Polyodon spathula ) hunts plankton using thousands of tiny passive electrons located on its long snout, or pulpit. The paddlefish is capable of detecting electric fields that oscillate at 0.5-20 Hz, and large groups of plankton produce this type of signal. View: Electroreceptors in paddlefish
Electric fish use an active sensory system to investigate the environment and create active electrodynamic imaging.
In 1973, it was shown that Atlantic salmon has conditioned the heart's response to an electric field with forces similar to those found in the oceans. "This sensitivity allows migratory fish to align themselves upstream or downstream in ocean currents without a fixed reference."
Magnetoception, or magnetoreception, is the ability to detect the direction at hand based on the Earth's magnetic field. In 1988, the researchers found iron, in the form of a single domain magnetite, in the skull of salmon sockeye. Amount is enough for magnetoception.
Salmon regularly migrate thousands of miles to and from their breeding grounds.
Salmon spend their early lives on the river, and then swim into the ocean where they live their adult life and get most of their body mass. As they grow older, they return to the river to lay their eggs. Usually they return with tremendous precision to the birth river where they were born, and even to the very nesting place of birth. It is estimated that, when they are in the ocean, they use magnetoception to find the general position of their christmas river, and once close to the river, that they use their sense of smell to the house above the river entrance and even their christmas day to lay their eggs.
After several years of wandering in the ocean, most of the salmon that survived returned to the same birth river where they gave birth. Then most of them swim in the river until they reach the very egg-laying ground that was their original birthplace.
There are various theories about how this happened. One theory is that there are geomagnetic and chemical signals that salmon use to guide them back to their birthplace. Fish may be sensitive to the Earth's magnetic field, allowing the fish to adjust to the ocean, so that it can navigate back to the mouth of the Christmas stream.
Pain
Experiments conducted by William Tavolga provide evidence that fish have a response of pain and fear. For example, in the Tavolga experiment, the toadfish grunted when electrocuted and over time they grunted just by looking at the electrodes.
In 2003, Scottish scientists at the University of Edinburgh and Roslin Institute concluded that the behavior of rainbow trout is often associated with pain in other animals. Bee venom and acetic acid injected into the lips cause the fish to shake their bodies and rub their lips along the sides and floors of their tank, which the researchers conclude is an attempt to relieve pain, similar to what mammals do. Neurons are fired in patterns that resemble human neuronal patterns.
Professor James D. Rose of the University of Wyoming claims the study is flawed because it does not provide evidence that fish have "consciousness, especially a kind of meaningful consciousness like us". Rose argues that because the brains of fish are so different from the human brain, the fish may not be aware of the human way, so a reaction similar to that of a human reaction to pain has another cause. Rose has published a study a year earlier on the grounds that fish can not feel pain because their brains lack the neocortex. However, animal behavioralist Temple Grandin argues that fish can still have consciousness without the neocortex because "different species can use different structures and brain systems to handle the same function."
Animal welfare supporters raise concerns about possible fish suffering caused by fishing. Some countries, like Germany have banned certain types of fish, and the British RSPCA are now demanding cruel people for fishing.
See also
References
Further reference
- Collin SP and Marshall NJ (Eds) (2003) Sensoric Processing in the Water Environment Springer. ISBN: 9780387955278.
- Green, WW and Zielinski BS (2013) "Chemoreception" In: DH Evans, JB Claiborne and S Currie (Eds) Fish Physiology , 4th ed., pp. 345-373, Press CRC. ISBN: 9781439880302.
- Popper AN and Fay RR (1993) "Voice detection and processing by fish: critical review and major research question" (2 parts) Brain, behavior and evolution , 41 (1): 14-25. doi: 10.1159/000338719 PDF part 1 PDF part 2
- Stevens, Martin (2013) Sensory, Behavior, and Evolutionary Ecology Oxford University Press. ISBN: 9780199601783.
- Webb JF, Fay RR and Popper AN (2008) Fish Bioacoustics Springer. ISBN: 9780387730288.
Source of the article : Wikipedia
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