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A dragonfly in its final moult, undergoing metamorphosis, it begins transforming from its nymph form to an adult. Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. [1]
Young frog with a stumpy tail, metamorphosis nearly complete. Adults. A Xenopus laevis froglet after metamorphosis. Adult frogs may live in or near water, ...
The presence of fish in breeding ponds shortens mating periods, whereas many other frog species avoid breeding in such conditions. All tested frog species, K. senegalensis included, immediately stopped breeding activity when the catfish species Clarias gariepinus is introduced. [12] They take 50–60 days to complete metamorphosis. [11]
Gosner stage is a generalized system of describing stages of embryonal and larval development in anurans (frogs and toads). The Gosner system includes 46 numbered stages, from fertilized embryo (stage 1) to the completion of metamorphosis (stage 46). It was introduced by Kenneth Gosner in 1960. [2]
Frogs, toads and salamanders all hatch from the egg as larvae with external gills. Metamorphosis in amphibians is regulated by thyroxine concentration in the blood, which stimulates metamorphosis, and prolactin, which counteracts thyroxine's effect.
The tadpoles develop into a streamlined, or elongated, shape and reach a length of 50mm (2 inches) preceding their complete metamorphosis, which occurs over an average period of 75 days in the summer. Similar to the metamorphised adults they have a rounded head with golden eyes, although the sides of the iris are more shaded.
After metamorphosis is complete, the frog is around the same length. The juveniles initially grow rapidly, reaching 45 mm within two months, 50–60 mm within half a year, before growth slows. [41] months, and increase in length more slowly after that. [41] Once sexual maturity is reached, the frogs' physical growth is very slow. [41]
Tadpoles average slightly over 1 in (3 cm) long and require 80 to 180 days to complete metamorphosis in the field. [6] The Mississippi gopher frog possesses several defense mechanisms in its immune system that are unique to Rana sevosa. The frog's innate immune system is adept at recognizing outside prokaryotic pathogens.