Any living organism - it is a perfect system, and if the circulatory, nervous and other organ systems allow us to exist, then the senses - it is just that, with the help of which the organism learns and perceives the environment.In addition, each class of animal organisms has its own characteristics.
Senses fish
The representatives of this class of animals have a fairly developed eyes, which consist of the retina, lens and cornea.The principal difference between these bodies is that when the image pickup lens does not change the curvature, as in other vertebrates, - it simply moves relative to the cornea, thereby focusing view.
There fish and organs of hearing, which are three semi-circular, mutually perpendicular channel.Some representatives have the same so-called Weber organ which connects the cavity of the inner ear with the air bladder, operating in this case as a sound resonator.Receptors that perceive taste and smell can be located not only in the mouth and nostrils, but also scattered throughout the body.
Another interesting body - a lateral line, which is a set of channels associated with the nerve fibers.The lateral line is specifically developed for those fish that have no eyes - because of it they can perceive the outside world and maintain balance.
It's no secret that some fish may respond to electric fields and even generate electrical pulses via special cells and nerve fibers.
Senses amphibians
Senses members of this class have been more adapted to life in the air.For example, the eyes of them already have eyelids and nictitating membrane, which carries out a moisturizing and protective functions.The lens can change its size depending on the lighting.
In addition, amphibians have olfactory bags that open out the nostrils.An animal can only perceive odors in the air.As for the hearing, the amphibians have formed the middle ear and eardrum and a small bone called the stapes.All mechanical
receptors located in the skin tissues.Primitive aquatic amphibians and tadpoles still remains a sideline.
Senses reptiles
The representatives of this class of the senses are more developed and have adapted to life in the air.It is very important for these animals are the eyes, which formed more than amphibians - has developed muscles that are attached to the lens and can change its curvature to focus the image.In addition, the reptiles there are real tear glands, the secret which protects the animal's eyes from drying out.There are movable eyelids.
Such animals have choanae (internal nostrils), which are located closer to the throat, which greatly facilitates breathing during meals.It is proved that reptiles are much more sensitive to odors than the representatives of the class of amphibians.
organs of taste are represented by specific bodies - the taste buds, which are located in the throat.And between the eyes and the nose is the so-called front pit, which allows to react to changes in temperature.For example, some snakes was this body allows you to quickly find food.
organs of hearing are not very well formed and resemble hearing aids amphibians.In reptiles, there are middle and inner ear to the eardrum and the stapes - a small bone that transmits vibrations to the eardrum.Hearing in the life of these animals is not particularly important.For example, snakes, he is not well developed.
As can be seen, the senses gradually changed in the course of evolution, adapting to survive in certain conditions, become more complex and functional.
