Metamorphosis (biology)

Metamorphosisbiologyphysical development ofindividual after birth or hatching involving significant changeform as well as growthdifferentiation. It usually accompanieschangehabitat orhabits but may occur without such change. It was once thought thatthose cases whereanimal's habitat remains unchanged metamorphosis followedseriesforms representing evolutionary ancestors ofspeciesquestion (see ontogeny recapitulates phylogeny), but thisno longer thoughtbecase.

The first typemetamorphosisillustrated by many insectsby amphibians. Immature dragonfliesaquatic thoughadultsflying insects,frogs undergometamorphosis from an aquatic tadpolean air-breathingpartially terrestrial adult form. Changehabitsillustrated bytransformation offree-swimming youngmany aquatic invertebrates into sessile adults, anddevelopmentbutterfliesmoths from caterpillarschewing mouthparts into flying insectssucking mouthparts.

The second typeillustrated by many crustacean species, whose young undergo significant physical metamorphosis without changing habits or habitat significantly.

The immature stages ofspecies that undergoes metamorphosisdesignated byterm larva. Incomplex metamorphosismany insect species, however, onlyfirst stagecalledlarvasometimes even that bearsdifferent name;distinction depends uponnature ofmetamorphosis.

Some insects hatch fromegg already havinggeneral form ofadult, andmetamorphosisadult formusually marked mainly bydevelopmentwings. This typemetamorphosiscalled gradual or incomplete metamorphosis, andyoungcalled nymphs, or naiads when aquatic. Insectscomplete metamorphosis, pass throughlarval stagethen enter an inactive state known aspupa, finally emerging asadult form. A numberbeetle speciesStrepsiptera undergo hypermetamorphosis, withsequencedifferent larval forms preceding pupation.

In metamorphosis,insectsin their junvenile form longer than eggs.  But while some speciesbeing adults longer, othersinreverse situation. The time infollowing tablenot accumulative. Cicada, mayflycockroach have incomplete metamorphosis,its youngcalled nymphnot larva.

Species	Egg	Larva/Nymph	Pupa	Adult
Bluebottle Fly	1 day	8 days	9 days	35 days
Ladybug	4 days	18 days	15 days	9 months
Large White Butterfly	14 days	1 month	6 months	2 months
Periodical Cicada	1 month	17 years	no such stage	2 months
Mayfly	1 month	3 years		1 day
Cockroach	1 month	3 months		9 months