Sea, river and lake fish
We all know that water is life. Without water can’t live no living creature. And the first life originated in water. Fish one of the many live organisms living in the aquatic environment. They live in the oceans and seas, rivers and lakes. You can see them in the pond and the stream, in the waters of caves and even in puddles. In nature, there are over 25,000 species of fish, and they are divided into two classes: Bony fish (more than 23 000 species); Cartilaginous fishes (9000 species).
To the class of cartilaginous fish include sharks, rays and chimeras. To the class of bony fish include salmon. okuneobraznyh. preobrazenie. clupeiformes. Cypriniformes, catfishes, wildcookie, flatfish, coloscopie.
Fish are cold blooded vertebrates. their streamlined body covered with scales. They breathe with gills, and with the help of fins and tail to swim. Water entering the body through the mouth, passes through the gills, and spilling over her holes. Oxygen enters the bloodstream of fish through the thin membrane of the gills. Do fish have paired fins (pectoral and abdominal), which are located on the sides and unpaired, located on the median vertical plane of the body (back, tail, and anal). Fins help fish to steer, brake, accelerate and keep the balance. Fish’s mouth has a different shape and fringed lip. The eyes are often sagopa sides of the head, rarely on the top of the head. The nostrils are paired and have the shape of the fossa is the olfactory organ. The fish has a organ of hearing (inner ear) organs of taste (lips and mouth). Mucous cells cover the body of the fish to form scales. The color of the fish depends on pigment cells. They are well camouflaged in the depths of the seas and oceans, having different body color – nature took care of that. The basis of the fish’s body is the skeleton. They have a nervous system that responds to pain and gives the team, ensuring the coordination of movement. Almost all fish are predators. They eat plankton, algae, other fish, water animals. Fish reproduce by spawning, but there are also viviparous.
Permanent pollution of the water environment and over-fishing threatens many species to extinction. After all, it is we humans intrude into their lives, we break the rhythm and life cycle. Let’s keep the wonderful realm of Pisces and will admire them for years to come, and better century.