Transformation

Definition

A marked change in form, structure, or identity during development, evolution, or ecological succession. In entomology, transformation most often denotes complete metamorphosis (holometaboly), wherein a larva reorganizes through a pupal stage into an adult with radically different morphology, physiology, and behavior. In molecular biology, transformation refers to the uptake and incorporation of exogenous genetic material by a cell, a mechanism exploited in insect biotechnology and microbial studies of arthropod symbionts. In ecology, transformation describes the conversion of one ecosystem state to another (e.g., forest to grassland) or the successional replacement of arthropod assemblages following disturbance.

Etymology

From Latin transformatio, from transformare (to change in shape), from trans- (across, beyond) + formare (to shape).

Example

In butterflies, the transformation from caterpillar to adult involves histolysis of larval tissues and histogenesis of imaginal discs during pupation; in bacteria, transformation with plasmids enables the production of transgenic Drosophila lines for gene-function studies.

Synonyms

• Metamorphosis
• transmutation
• conversion

Related Terms

• Metamorphosis
• holometabolous
• pupa
• Imaginal disc
• Horizontal gene transfer
• Ecological succession
• phenotypic plasticity

Usage Notes

Distinguish transformation (general or molecular) from metamorphosis (developmental, especially in insects). In molecular contexts, transformation contrasts with transduction (phage-mediated) and conjugation (cell-contact). Ecological transformation is sometimes reserved for regime shifts rather than gradual succession. Some arachnologists reserve 'transformation' for post-embryonic molts that dramatically alter habit (e.g., parasitiform mites shifting from feeding to dispersing morphs), though 'metamorphosis' is less commonly applied to arachnids.