Metamorphosis and Economic Importance of Frog

After external fertilization, frog eggs hatch within a few days into tadpoles that live at first on their own stored yolk. A newly hatched tadpole is fully aquatic, developing external gills followed by internal gills, and gradually undergoes metamorphosis into the air-breathing, carnivorous adult form: hind limbs appear first, then forelimbs, the tail and gills are progressively resorbed, the mouth widens and grows teeth and jaws, and the lungs become functional, completing the transition from an aquatic, plant/detritus-feeding larva to a terrestrial, insect-eating adult. Economically, frogs are valuable predators of insect pests and so help protect crops, are an important link in freshwater food chains, and in parts of India, the USA, Japan and China they are also used in traditional medicine and, regionally, eaten …