Devolution, de-evolution, or backward evolution (not to be confused with
dysgenics
Dysgenics (also known as cacogenics) is the decrease in prevalence of traits deemed to be either socially desirable or well adapted to their environment due to selective pressure disfavoring the reproduction of those traits.
The adjective "dysgeni ...
) is the notion that
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
can revert to supposedly more
primitive
Primitive may refer to:
Mathematics
* Primitive element (field theory)
* Primitive element (finite field)
* Primitive cell (crystallography)
* Primitive notion, axiomatic systems
* Primitive polynomial (disambiguation), one of two concepts
* Pr ...
forms over time. The concept relates to the idea that
evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
has
a purpose (teleology) and
is progressive (orthogenesis), for example that feet might be better than
hooves
The hoof (plural: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits, yet the rum ...
or
lungs than
gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...
s. However,
evolutionary biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life fo ...
makes no such assumptions, and