Biological devolution
From Wikipedia, the free encyclopedia
The term "devolution", which normally means a delegation of powers, is sometimes erroneously used to refer to the evolution of a species into more "primitive" forms. Many lay people see evolution as "progress", reflecting the ideas of Lamarckism. However, scientists recognize that evolution by natural selection is directionless, and so "devolution" is still actually evolution.
It should not be confused with "evo-devo" which is shorthand for evolutionary developmental biology.
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[edit] Misconceptions about evolution
- Species evolve because they need to in order to adapt to environmental changes.
Biologists refer to this misconception as teleology, the idea of intrinsic finality that things are "supposed" to be and behave a certain way, and naturally tend to act that way to pursue their own good. As the fossil record demonstrates that more than ninety nine percent of all species that ever lived are now extinct it is clear that most species do not evolve despite radical environmental changes. From a biological viewpoint, when species evolve it is not a reaction to necessity, but rather that the population contains variations with traits that favour their natural selection.
- Evolution means progress to more advanced organisms.
This presumes that there is somehow a preferred hierarchy of structure and function, for example that "feet are better than hooves" or "lungs are better than gills", and can lead to the idea that change to "less advanced" structure can be called "devolution". To biologists this is an aspect of teleology, the supposition that there is purpose or directive principle in the works and processes of nature. A biologist sees all such changes as evolution, since for the organisms possessing the changed structures, each is a useful adaptation to their circumstances. For example, hooves have advantages for running quickly on plains as horses do, and feet have advantages in climbing trees as the ancestors of humans did.
- Humans are the ultimate product or goal of evolution.
This belief is related to anthropocentrism, the idea that human existence is the point of all universal existence, and is a variation on the idea of "progress". To a biologist, describing the biological evolutionary process as goal-oriented would seem as ludicrous as a physicist claiming that the ultimate goal of gravity is to keep the Earth in its present orbit.
- Increasing complexity is the necessary outcome of evolution.
Biologists have evidence of many examples of decreasing complexity in the record of evolution. The lower jaw in fish, reptiles and mammals has seen a decrease in complexity, if measured by the number of bones. Ancestors of modern horses had several toes on each foot; modern horses have a single hoofed toe. Modern humans may be evolving towards never having wisdom teeth, and already have lost the tail found in many other mammals - not to mention other vestigial structures, such as the vermiform appendix or the nictating membrane.
[edit] Use of the term by opponents of evolution
As with other modern sciences, biology is based on a methodological assumption of philosophical naturalism to study and explain the natural world, without assuming the existence or nonexistence of the supernatural. In contrast, creationism and intelligent design are based on teleology in seeking to prove the existence of an organizing principle behind natural laws and phenomena. Opponents of evolution use the teleological argument for the existence of God, and seek to displace evolution as the central organizing concept in biology. To do so, some redefine "evolution" in their terms, and introduce "devolution" to show that evolution theory is incorrect.
Examples include Mastropaulo[1], who argues that "Change over time, 'definition one' of evolution, actually describes devolution to extinction, the exact opposite of evolution.... actual epidemiological data from human genetic disorders and fatal birth defects, identify 'natural selection,' the alleged 'primary mechanism' for evolution, as actually a mechanism for devolution to extinction, the exact opposite of evolution." and elsewhere[2], "Evolution is the development of an organism from its chemicals or primitive state to its present state. Devolution is the sequence toward greater simplicity or disappearance or degeneration."
The term has been used in the play Inherit the Wind, the character of Matthew Brady (representative of William Jennings Bryan) using the term to argue that "ape devolved from man", mocking evolutionary theory by offering an alternative he considers just as plausible.
The term was also popularized in the late 1960s by the musical group Devo (see Early Years), where it was used (initially) jokingly as a theme by members Gerald Casale and Bob Lewis.
