Metamorphosis,Retrogressive and progressive metamorphosis

Metamorphosis:

The changes which takes place in the organisms from juveline stage to adult stage is called metamorphosis.

The larval stage is quite different from adult stage.

Retrogressive metamorphosis:

In this process,larva posses advanced characters while the adult is retained or degenerated with primitive characters.

Urochordata exhibits retrogressive metamorphosis where the larva shows advanced characters and adult posses degenerated characters.

Progressive metamorphosis:

In this process,the adult stage is advanced than larval stage and larva posses degenerated characters, whereas adult posses advanced characters.

 It is seen in anurans of Amphibians.

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