Question

Bony/teleost fishes are characterized by
A. Cloaca
B. Air bladder
C. Placoid scales
D. Ventral mouth

Answer 1

Bony fish, any member of the superclass Osteichthyes, a bunch made up of the classes Sarcopterygii (lobe-finned fishes) and Actinopterygii (ray-finned fishes) within the phylum, including the great majority of living fishes and virtually all the world’s sport and commercial fishes.

Complete Answer:
Osteichthyes excludes the jawless fishes of the category Agnatha (hagfishes and lampreys) and also the cartilaginous fishes constituting the category Chondrichthyes (sharks, skates, and rays) but includes the 20,000 species and over 400 families of recent bony fishes (infraclass Teleostei) of the world, moreover as some primitive forms.

The primary characteristic of bony fishes may be a skeleton a minimum of partly composed of true bone (as opposition cartilage). Other features include, in most forms, the presence of a swim bladder (an air-filled sac to supply buoyancy), gill covers over the gill chamber, bony platelike scales, a skull with sutures, and external fertilization of eggs.

Bony fishes occur altogether in freshwater and ocean environments, including caves, deep-sea habitats, and thermal springs and vents. The range of shapes and behavioral habits is remarkable. Their body sizes range from tiny species to the large marlins and swordfishes.

Teleost, (infraclass Teleostei), any member of an outsized and intensely diverse group of ray-finned fishes. Along with the chondrosteans and also the holosteans, they're one among the three major subdivisions of the category Actinopterygii, the foremost advanced of the bony fishes. The teleosts include virtually all the world’s important sport and commercial fishes, yet as the way larger number of lesser-known species. Teleosts are distinguished primarily by the presence of a homocercal tail, a tail within which the upper and lower halves are about equal. The teleosts comprise some 30,000 species (about adequate for all other vertebrate groups combined), with new species being discovered annually. Teleosts point size from tiny minnows that are but one-third of an in. Long when fully adult to large marlins that exceed 3.4 metres.

Teleost fishes have evolved into many diverse shapes. A relatively simple teleost, a trout, is examined, its basic swimming motion could also be determined. Procession is provided by bending of the body and caudal fin; waves of muscular action pass from the top to the tail, pushing the sides of the body and tail against the water and forcing the fish forward. The structure of the tail and also the efficiency of the swimming mechanism are the prime characters that distinguish teleosts from other, “lower,” fishes. The fin and thus the anal fin are used partly to assist in stability and in turning and partly in forward locomotion. The paired pelvic or ventral fins and also the paired pectoral fins behind the head are accustomed to help stabilize the body and to point out the fish. The fusiform shape of the trout reduces the turbulence and drag of water flowing over the fish’s body, offering travel to the water.

The head of the fish must be adapted for feeding, breathing, and detecting prey and enemies. It must be relatively streamlined, offering as little resistance to the water as possible. The head of a trout is well formed for these functions by being fusiform but expandable, where necessary, to need in food and water. The fish forces the water in one direction, into the mouth, over the gills, and out the gill slits. Backflow is prevented by valves at the mouth and by the gill covers. The fish, however, can eject undesirable particles and water out the mouth by special action. The teleost head is efficient in having eyes and organs for the sense of smell located in optimum spots for seeing and smelling food.

Therefore, the correct option is B, air bladder.

Note: Some species, just like the tunas made teleost fishes extremely important to humankind as a food supply. In almost every part of the earth, local fishes are used as food by people in any respect stages of economic development. Additionally to being a commercial food resource, teleost fishes provide enjoyment to immeasurable people and in many countries of the world support an oversized sportfishing industry.

As aquarium subjects, both marine and, especially, small freshwater teleosts provide aesthetic beauty for various aquarists, supporting a multimillion-dollar industry. Part of the interest in teleosts as aquarium fishes comes from the great diversity of their anatomical structures, functions, and colour. Indeed, these fishes vary more in structure and behavior than do all the mammals, birds, reptiles, and amphibians combined.