Free Biology notes-Biology notes with diagrams and practicals

                              Naja (Cobra) #Comments Habit and Habitat:- Cobra is diurnal, shy, living in holes, under stones, mud walls, and in thick vegetation. It is oviparous, carnivorous, and feeds on frogs, rats, lizards, and other snakes.         Commonly known as Indian cobra/Nag. Body measures 2-3 meters in length and is wheatish (gehuwa) in colour. A most common and deadly poisonous snake. Head small and indistinct. The pupil is round. The neck can dilate into the hood. Hood is supported by ribs. Subcaudals in two rows. It is a smooth-scaled snake with black eyes. Reproduces sexually. They have an excellent sense of smell and night vision. Females are visually larger than males. Naja varies in length

                             Chelone  Comment:-  Habit and Habitat=> Chelone is a marine reptile. They come ashore only to lay eggs. Distributed in Indian, Pacific, Atlantic oceans and feed on algae. Chelone is commonly called as the green turtle. It is a marine, very common, and largest species of sea turtles. The body is covered by a shell, dorsal heart-shaped carapace, and a ventral plastron. Flipper-shaped limbs are present. They have retractile heads and small tails. Eyes with eyelids and nictitating membrane. Jaws are with horny sheath. Economically important as armor is also utilized and flesh is edible turtle soup.

                              Hemidactylus #Comments Habit and Habitat:- Hemidactylus has a worldwide distribution and is chiefly found in India, Europe, Asia, Africa, the USA, China, etc.                                                    Commonly called as house lizard/wall lizard. It is nocturnal in habit. During winter they Hibernate underwoods, logs, and crevices of the walls. They are as fast-runner diapsid. Usually feed on insects and small invertebrates. The body is approximately 25 cm in length. The Head is triangularly containing eyes, nostrils, and external ear opening. Eyes lack movable eyelids. Well-developed forelimbs and hindlimbs. Amphicoecus vertebrae. Lays calcified eggshells. They have a special characteristic, i.e. regenerative tail.

                                   Sphenodon #Comments Habits and Habitats:- Found on relatively inaccessible, islands off the coast of New Zealand. The habitat is cold and damp, with a temperature less than 70 degrees Fahrenheit, and a humidity level of about 80 percent.                                                     Sphenodon is Commonly called as tuatara. They are grey, olive or red in color. They can measure up to 80cm from head to tail-tip and weigh about 1.3 kg. They have a diapsid skull and lack external ears. The male Sphenodon displays a crest down the back of the neck, and another goes down the middle of the back. They have an acrodont tooth structure. They also possess a " parietal eye " on their head. The tuatara has a slow metabolism, thus lives a long...

                                Anabas # Comments => Habit and Habitat: Anabas is a common south Indian fresh-water fish. It can live out of water for a long time.                               Anabas is commonly called as climbing perch. Its body is covered by flat, bony, and rounded, cycloid scales. The dorsal and anal fin is well developed and provided with long backwardly directed spines. The same is with the operculum. Anabas can walk on land with the help of the dorsal or anal fin. Their tail is perfectly symmetrical and homocercal.

                                Labeo # Comments => Habit and Habitat: Labeo is found in ponds and rivers. They are vegetarians and bottom dwellers.                       Labeo is commonly known as Rohu in Hindi. The body is covered with large overlapping cycloid scales. The snout is obtuse and blunt. The body is divided into three distinct parts head, trunk, and tail. A pair of filamentous barbels are present. The scales are flat, bony with rounded edges, hence called cycloid scales. They are of taxonomic value. Dorsal, anal, caudal, paired pectoral and ventral fin with soft fin rays are present. The caudal fin is divided into two equal lobes. Rohu has a great food value in India.

                               Diodon  # Comments => Habit and Habitat: Diodon is confined to tropical seas, living along near reefs, caves, or ledges, hunting crustaceans and molluscs at night.  Diodon is commonly known as porcupine fish. Its body is rounded, globose, and covered with numerous flexible spines, the organs of defense; they are erected to protect the fish from any external enemy's attack. This fish can also inflate its body by swallowing water. The scales are generally spiny or bony. The caudal fin is rounded and tilted Upwards. The anal fin is opposite to the dorsal fin. There are 3 gills present. The belly is inflatable. The skin is leathery. Although porcupine fishes are poisonous, they are eaten as food fish and are an exotic delicacy in Japan and Indonesia.

                              Heteropneuptes # Comments => Habit and Habitat: It is found in rivers, estuaries, lakes, ponds, and ditches. They usually move in shoals.                                It is commonly called Singhi in Hindi. Its head is flattened and covered with thin skin. Flat snout with mouth and 4 pairs of barbels. The pectoral fin is quite strong with poisonous spines. The dorsal fin is short and without a spine. The anal fin is elongated and reaches up to the caudal fin but is separated by a deep notch. It has an accessory respiratory organ. Air bladder is also present. It is very popular as food fish and for its medicinal properties.

                              Exocetus # Comments => Habit and Habitat: Exocetus is found in the sea, often skittering near the boats. It is pelagic and feeds in small fishes and prawns. They form shoals of fish.                                                     Exocetus is commonly known as flying fish. Their body is covered with overlapping cycloid scales. Dorsal and anal fins are short and supported by fin rays. It has a pair of large pectoral fins enormously well developed to form a wing-like structure, which is used as a parachute to survive out of water. An air bladder is also present. Several black spots are present on the pectoral fin. Their tail is hypobatic. It serves as a food delicacy.                 

                             ANGUILLA # Comments  => Habit and Habitat: Anguilla is a freshwater voracious and catadromous fish that can live outside water for several hours. Anguilla is commonly called as the eel. Its body is slender, elongates, and snake-like. Operculum covers the gill slits on either side. A continuous fin is formed by the fusion of the dorsal fin, anal fin, and caudal fin. The body is covered by minute scales embedded in the skin and arranged obliquely at right angles to one another. Air bladder is present.

                                   Mystus  #Comments  => Habit and Habitat: Mystus is found in rivers, ponds, tanks, floodplain areas. It inhabits in flowing water system also found in standing water with macrophytes and sandy & muddy bottom.                                It is commonly known as Adriai Tenyer. Its body is divided into head, trunk, and tail.  The snout is spatulated. Dorsal, pectoral, pelvic, caudal and ventral fins are present. The first dorsal fin contains a weak and raised dorsal spine whereas the second dorsal fin is a much smaller adipose fin. This fish is used as a common man's food but aquarist like it as ornamental fish.  The back is slightly darker, usually pale. Mouth lacks teeth.