Tadpole to Toad and Insect Metamorphosis

These vocabulary flashcards cover the developmental stages of amphibians from tadpole to adult toad, the hormonal control of metamorphosis, and the processes of insect metamorphosis.

Muscle segments

Structural units of a tadpole resemble those of a fish.

Hindlimb development period

Occurs about $8$ to $9$ weeks after hatching, appearing as a bulge between the trunk and tail.

Opercula

The structures that hide the forelimbs during their early development in the tadpole.

Forelimb emergence

The process where the left forelimb grows through the spout followed by the right forelimb bursting through the operculum.

Tadpole diet change

The transition to feeding on small dead animals which results in the shortening of the intestine and narrowing of the abdominal region.

Internal gill degeneration

The process that occurs as the lungs develop and the tadpole begins taking air in through its nostrils and mouth.

Tail absorption

The process occurring at about $3$ months of age where the tail shortens to provide nutrition for the metamorphosing tadpole.

Thyroxine

The hormone produced by the thyroid gland that controls metamorphosis in amphibians.

Parthenogenesis

The development of young ones from unfertilized eggs, as seen in aphids and bees.

Incomplete metamorphosis

A type of insect development where the egg hatches into a miniature adult known as a nymph.

Nymph

The stage of an insect that resembles a miniature adult and undergoes approximately five moults.

Ecdysis

The process of moulting where an insect nymph sheds its skin to increase in size.

Instars

The specific stages between successive moults in an insect's development.

Imago

The fully grown adult insect that emerges after the final stage of moulting.

Toad sexual maturity

The stage in development reached when a toad is about $3$ years old.