Direct development is a concept in

biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...

. It refers to forms of growth to adulthood that do not involve

metamorphosis 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 different ...

. An animal undergoes direct development if the immature organism resembles a small adult rather than having a distinct

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

l form. A frog that hatches out of its egg as a small frog undergoes direct development. A frog that hatches out of its egg as a

tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

does not. Direct development is the opposite of complete metamorphosis. An animal undergoes complete metamorphosis if it becomes a non-moving thing, for example a

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

in a cocoon, between its larval and adult stages.

Examples

*Most frogs in the genus ''

Callulina ''Callulina'' (commonly known as the warty frogs) is a small genus of frogs in the family Brevicipitidae with nine members in Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Grea ...

'' hatch out of their eggs as froglets. *

Springtails Springtails (class Collembola) form the largest of the three lineages of modern Hexapoda, hexapods that are no longer considered insects. Although the three lineages are sometimes grouped together in a class called Entognatha because they have in ...

and

mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order ...

, called ametabolous insects, undergo direct development.

References

Developmental biology Animal anatomy {{biology-stub