A third division takes place in the four cells, this time at right angles to the other two, round the "equator", forming eight cells of which the lower four are slightly larger than the upper four. Microbodies Microtubules and Microfilament, Ecological imbalance and their consequences, Grassland ecosystem and Energy flow through an ecosystem, Food chain, Food web and ecological pyramids (Functional aspect of ecosystem), Introduction to forest and Water resources, Causes of Extinction of Wildlife and It's Conservation, National parks, Wildlife reserves and Conservation area of Nepal, Amino acids, Proteins Lipids or Fats and Steroids ( Biomolecules ), General approach to understand Life process. On moving from water to land or over rough ground the frog will crawl rather than leap. In winter they hibernate in the sense that they are dormant and do not feed. After about ten days the jelly immediately round the tadpole liquefies and the tadpole can be seen moving about inside. Flow of energy and information through the cell. In extreme hot temperature i.e. It sticks them together and prevents their being swept away or eaten. The eyes have movable lids but, in addition, the whole eyeball can be withdrawn farther into the head by muscles. Frogs are cold-blooded, they lay their eggs in fresh water. In the skin are mucous glands which make the slimy fluid that covers the body. The long intestine is adapted to the digestion of an exclusively vegetable diet. In early spring, during the breeding season, frogs-spend their time in ponds and lakes with a steady flow of water. Its nostrils are situated so that air can be breathed while the frog is swimming at the surface; they can also be closed. During and after activity it may breathe air into its lungs by gulping movements of the floor of its mouth. In four years the frog will be old enough to breed. They also have contain the ability to breathe underwater when they are very young, they grow gills or breathe air when they are older. It has a loose-fitting moist skin. The tadpole is quite black, and the rudimentary external gills are visible, but it breathes through its skin at this stage. The amphibia are adapted, in general, to moving, feeding and breathing on land as well as in fresh water. spot and tympanum on the upper side and throat on the lower side. Sufficient oxygen must be able to diffuse through the jelly and the egg to allow the vital processes to go on. It is a light patch of skin dorsally and median, in front of the eye. Thus, although fertilization is external, the pairing of frogs ensures that this happens. Other present-day members of the group are the toads, newts and salamanders. Two pair of limbs arises laterally from the trunk. 7. They lie up in the mud at the bottom of ponds, in damp moss or holes in the ground and their eyes, mouth and nostrils are closed. Adult frogs are carnivorous, feeding on worms, beetles, flies and other insects. They are cosmopolitan found in fresh water or live in or near water like ponds, pools, stream, lake etc or damp places. Behind the eyes are circular ear-drums. The eyes have movable lids but, in addition, the whole eyeball can be withdrawn farther into the head by muscles. Vigorous wriggling movements of the body and tail propel the tadpole through the water in a similar way to a fish but with less speed and precision. Eyes and nostrils are easily seen at this time. The predominant colours in the common frog are green, yellow, brown and black, with whitish areas on the underside. In swallowing, the eyes are often pulled farther into the head and press down on the prey. Shortly after fertilization, the time depending partly on the temperature, the nucleus of the egg divides into two smaller nuclei which separate. It has immovable upper eyelid and movable lower eyelid. The sliminess makes the frog difficult to catch and keeps the skin moist. In the water the webbed hind feet provide a greater surface area for pushing backwards on the water. The moist lining of the large mouth is also a respiratory surface. The lungs can be inflated to many times their relaxed size, so apparently inflating the entire frog. 12. The energy and raw materials for this process come from the yolk. A long, coiled intestine has developed and can be seen through the skin of the abdomen. The head is triangular, flattened with short narrow blunt interior end called snout. In general, frogs have protruding eyes, no tail, and strong, webbed hind feet. The tail elongates and develops a broad transparent web along its dorsal and ventral surfaces. It is also … A trunk is dorsoventrally flattened, broad and the back side of which is raised to form a hump due to the connection between pelvic girdle and vertebra. Although the tadpoles are merely attached to, and not feeding on the waterweed, a good deal of spasmodic wriggling takes place in the clusters of tadpoles. Its eyes protrude in such a way that they are above water when the rest of the body is immersed. Amphibians are known for living on both land and water. The cells are very numerous and too small to be seen even with a hand lens. It is also the outer appearance. The hind-limb buds near the junction of the body and tail begin to grow and develop into perfect legs. The fold of skin enclosing the space outside the gills is called the operculum. When the frog is inactive the skin absorbs enough oxygen to meet its needs. By now the external gills have shrivelled and been reabsorbed into the body. So, they are protected in their environment.Colour is due to chromatophores. The dorsal side is green in colour with a yellow mid-dorsal line which extends from the tip of snout to vent. 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