Metamorphosis in Frogs
தவளை உருமாற்றம்
Do not confuse metamorphosis with simple growth. It is a radical, hormone-driven structural overhaul. If you miss the larval stage, you miss the entire evolutionary strategy of the Anura order.
The idea
The development of a frog involves a larval stage called a tadpole. The tadpole undergoes metamorphosis to transform into the adult frog.
Why it matters
It allows the organism to occupy different ecological niches during different life stages, reducing competition between larvae and adults.
NEET lens
The frog's life cycle includes a distinct larval stage known as the tadpole. This tadpole undergoes metamorphosis to transform into the adult frog. Remember: Metamorphosis is the critical transition point for NEET questions on developmental biology.
Introduction
Metamorphosis in frogs is the process by which the aquatic larval tadpole transforms into the terrestrial adult frog through dramatic structural changes.
Core concept
Stages: Egg → tadpole (aquatic, fish-like, gills, tail, no legs) → metamorphosis (hormonal trigger — thyroxine) → juvenile frog (lungs, 4 legs, no tail) → adult frog. Key changes: gills → lungs, tail absorbed, legs develop, gut shortens (herbivore tadpole → carnivore frog).
Go deeper
Thyroxine (thyroid hormone) triggers metamorphosis in amphibians. Iodine deficiency → no thyroxine → tadpole cannot metamorphose and remains as permanent neotenic larva (e.g., axolotl). Prolactin inhibits metamorphosis.
From Class 10
Tadpoles look completely different from adult frogs. This transformation is called metamorphosis.