Devolution (biology)
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Devolution, de-evolution, or backward evolution (not to be confused with
dysgenics Dysgenics refers to any decrease in the prevalence of traits deemed to be either socially desirable or generally adaptive to their environment due to selective pressure disfavouring their reproduction. In 1915 the term was used by David Starr J ...
) is the notion that
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
can revert to supposedly more primitive forms over time. The concept relates to the idea that
evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
has a divine purpose (
teleology Teleology (from , and )Partridge, Eric. 1977''Origins: A Short Etymological Dictionary of Modern English'' London: Routledge, p. 4187. or finalityDubray, Charles. 2020 912Teleology. In ''The Catholic Encyclopedia'' 14. New York: Robert Appleton ...
) and is thus progressive (
orthogenesis Orthogenesis, also known as orthogenetic evolution, progressive evolution, evolutionary progress, or progressionism, is an Superseded theories in science, obsolete biological hypothesis that organisms have an innate tendency to evolution, evolve ...
), for example that
feet The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up of ...
might be better than
hooves The hoof (: 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; the ruminants with ...
, or
lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s than
gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, 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 r ...
s. However,
evolutionary biology Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth. In the 1930s, the discipline of evolutionary biolo ...
makes no such assumptions, and
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
shapes
adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...
s with no foreknowledge or foresights of any kind regarding the outcome. It is possible for small changes (such as in the frequency of a single gene) to be reversed by chance or selection, but this is no different from the normal course of evolution and as such de-evolution is not compatible with a proper understanding of evolution due to natural selection. In the 19th century, when belief in orthogenesis was widespread, zoologists such as
Ray Lankester Sir Edwin Ray Lankester (15 May 1847 – 13 August 1929) was a British zoologist.New International Encyclopaedia. An invertebrate zoologist and evolutionary biologist, he held chairs at University College London and Oxford University. He was th ...
and
Anton Dohrn Felix Anton Dohrn FRS FRSE (29 December 1840 – 26 September 1909) was a prominent German Darwinist and the founder and first director of the first marine-biological and zoological research station in the world, the Stazione Zoologica in Nap ...
and palaeontologists
Alpheus Hyatt Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Hyatt served as the founding president of the American Society of Naturalists from 1883 to 1884 and was the founding editor of the journal '' T ...
and
Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyology, ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited wit ...
advocated the idea of devolution. The concept appears in
Kurt Vonnegut Kurt Vonnegut ( ; November 11, 1922 – April 11, 2007) was an American author known for his Satire, satirical and darkly humorous novels. His published work includes fourteen novels, three short-story collections, five plays, and five nonfict ...
's 1985 novel '' Galápagos'', which portrays a society that has evolved backwards to have small
brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...
s. Dollo's law of irreversibility, first stated in 1893 by the palaeontologist
Louis Dollo Louis Antoine Marie Joseph Dollo (; 7 December 1857 – 19 April 1931) was a Belgian palaeontologist, known for his work on dinosaurs. He also posited that evolution is not reversible, known as Dollo's law. Together with the Austrian Othenio Ab ...
, denies the possibility of devolution. The evolutionary biologist
Richard Dawkins Richard Dawkins (born 26 March 1941) is a British evolutionary biology, evolutionary biologist, zoologist, science communicator and author. He is an Oxford fellow, emeritus fellow of New College, Oxford, and was Simonyi Professor for the Publ ...
explains Dollo's law as being simply a statement about the improbability of evolution's following precisely the same path twice.


Context

The idea of devolution is based on the presumption of
orthogenesis Orthogenesis, also known as orthogenetic evolution, progressive evolution, evolutionary progress, or progressionism, is an Superseded theories in science, obsolete biological hypothesis that organisms have an innate tendency to evolution, evolve ...
, the view that
evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
has a purposeful direction towards increasing complexity. Modern evolutionary theory, beginning with Darwin at least, poses no such presumption; further, the concept of evolutionary change is independent of either any increase in complexity of organisms sharing a gene pool, or any decrease, such as in
vestigiality Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
or in loss of genes.Dougherty, Michael J
Is the human race evolving or devolving?
''
Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...
'' July 20, 1998.
Earlier views that species are subject to "cultural decay", "drives to perfection", or "devolution" are practically meaningless in terms of current (neo-)Darwinian theory. Early scientific theories of
transmutation of species The Transmutation of species and transformism are 18th and early 19th-century ideas about the change of one species into another that preceded Charles Darwin's theory of evolution through natural selection. The French ''Transformisme'' was a ter ...
such as
Lamarckism Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also calle ...
perceived species diversity as a result of a purposeful internal drive or tendency to form improved adaptations to the environment. In contrast, Darwinian evolution and its elaboration in the light of subsequent advances in biological research, have shown that
adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...
through
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
comes about when particular heritable attributes in a population happen to give a better chance of successful reproduction in the reigning environment than rival attributes do. By the same process less advantageous attributes are less "successful"; they decrease in frequency or are lost completely. Since Darwin's time it has been shown how these changes in the frequencies of attributes occur according to the mechanisms of
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian ...
and the laws of inheritance originally investigated by
Gregor Mendel Gregor Johann Mendel Order of Saint Augustine, OSA (; ; ; 20 July 1822 – 6 January 1884) was an Austrian Empire, Austrian biologist, meteorologist, mathematician, Augustinians, Augustinian friar and abbot of St Thomas's Abbey, Brno, St. Thom ...
. Combined with Darwin's original insights, genetic advances led to what has variously been called the modern evolutionary synthesis or the neo-Darwinism of the 20th century. In these terms evolutionary adaptation may occur most obviously through the natural selection of particular
allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...
s. Such alleles may be long established, or they may be new
mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...
s. Selection also might arise from more complex
epigenetic In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in ...
or other
chromosomal A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most importa ...
changes, but the fundamental requirement is that any adaptive effect must be
heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cell (biology), cells or orga ...
. The concept of devolution on the other hand, requires that there be a preferred hierarchy of structure and function, and that evolution must mean "progress" to "more advanced" organisms. For example, it could be said that "feet are better than
hooves The hoof (: 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; the ruminants with ...
" or "
lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s are better than
gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, 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 r ...
s", so their development is "evolutionary" whereas change to an inferior or "less advanced" structure would be called "devolution". In reality an evolutionary biologist defines all heritable changes to relative frequencies of the genes or indeed to
epigenetic In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in ...
states in the gene pool as evolution. All gene pool changes that lead to increased fitness in terms of appropriate aspects of reproduction are seen as (neo-)Darwinian adaptation because, 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, which benefits horses, and feet offer advantages in climbing trees, which some ancestors of humans did. The concept of devolution as regress from progress relates to the ancient ideas that either life came into being through special creation or that humans are the ultimate product or goal of evolution. The latter belief is related to
anthropocentrism Anthropocentrism ( ) is the belief that human beings are the central or most important entity on the planet. The term can be used interchangeably with humanocentrism, and some refer to the concept as human supremacy or human exceptionalism. From a ...
, the idea that human existence is the point of all universal existence. Such thinking can lead on to the idea that species evolve because they "need to" in order to adapt to environmental changes. Biologists refer to this misconception as
teleology Teleology (from , and )Partridge, Eric. 1977''Origins: A Short Etymological Dictionary of Modern English'' London: Routledge, p. 4187. or finalityDubray, Charles. 2020 912Teleology. In ''The Catholic Encyclopedia'' 14. New York: Robert Appleton ...
, the idea of
intrinsic finality Intrinsic finality is the idea that there is a natural good for all beings, and that all beings have a natural tendency to pursue their own good. It is an underlying principle of both teleology and moral objectivism. The concept was summarized b ...
that things are "supposed" to be and behave a certain way, and naturally tend to act that way to pursue their own good. From a biological viewpoint, in contrast, if species evolve it is not a reaction to necessity, but rather that the population contains variations with traits that favour their
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
. This view is supported by the fossil record which demonstrates that roughly ninety-nine percent of all species that ever lived are now extinct. People thinking in terms of devolution commonly assume that progress is shown by increasing complexity, but biologists studying the
evolution of complexity The evolution of biological complexity is one important outcome of the process of evolution. Evolution has produced some remarkably complex organisms – although the actual level of complexity is very hard to define or measure accurately in biolog ...
find 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 hooved toe. Modern humans may be evolving towards never having
wisdom teeth The third molar, commonly called wisdom tooth, is the most posterior of the three molars in each quadrant of the human dentition. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs between late teens a ...
, and already have lost most of the
tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...
found in many other mammals - not to mention other
vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
structures, such as the
vermiform appendix The appendix (: appendices or appendixes; also vermiform appendix; cecal (or caecal, cæcal) appendix; vermix; or vermiform process) is a finger-like, blind-ended tube connected to the cecum, from which it develops in the embryo. The cecum ...
or the
nictitating membrane The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. Most ...
. In some cases, the level of organization of living creatures can also “shift” downwards (e.g., the loss of multicellularity in some groups of protists and fungi). A more rational version of the concept of devolution, a version that does not involve concepts of "primitive" or "advanced" organisms, is based on the observation that if certain genetic changes in a particular combination (sometimes in a particular sequence as well) are precisely reversed, one should get precise reversal of the evolutionary process, yielding an
atavism In biology, an atavism is a modification of a biological traits structure or behavior whereby an ancestral genetic trait reappears after having been lost through evolutionary change in previous generations. Atavisms can occur in several ways, ...
or "throwback", whether more or less complex than the ancestors where the process began. At a trivial level, where just one or a few mutations are involved, selection pressure in one direction can have one effect, which can be reversed by new patterns of selection when conditions change. That could be seen as reversed evolution, though the concept is not of much interest because it does not differ in any functional or effective way from any other adaptation to selection pressures.


History

The concept of degenerative evolution was used by scientists in the 19th century; at this time it was believed by most
biologists A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in ...
that evolution had some kind of direction. In 1857 the physician
Bénédict Morel Bénédict Augustin Morel (22 November 1809 – 30 March 1873) was a French psychiatrist born in Vienna, Austria. He was an influential figure in the field of degeneration theory during the mid-19th century. Biography Morel was born in Vienna, ...
, influenced by
Lamarckism Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also calle ...
, claimed that environmental factors such as taking
drugs A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via inhalation, injection, smoking, ingestio ...
or
alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...
would produce
social degeneration Social degeneration was a widely influential concept at the interface of the social and biological sciences in the 18th and 19th centuries. During the 18th century, scientific thinkers including Georges-Louis Leclerc, Comte de Buffon, Johann Fri ...
in the offspring of those individuals, and would revert those
offspring In biology, offspring are the young creation of living organisms, produced either by sexual reproduction, sexual or asexual reproduction. Collective offspring may be known as a brood or progeny. This can refer to a set of simultaneous offspring ...
to a primitive state. Morel, a devout
Catholic The Catholic Church (), also known as the Roman Catholic Church, is the List of Christian denominations by number of members, largest Christian church, with 1.27 to 1.41 billion baptized Catholics Catholic Church by country, worldwid ...
, had believed that mankind had started in perfection, contrasting modern humanity to the past. Morel claimed there had been "Morbid deviation from an original type". His theory of devolution was later advocated by some biologists. According to Roger Luckhurst:
Darwin soothed readers that evolution was progressive, and directed towards human perfectibility. The next generation of biologists were less confident or consoling. Using Darwin's theory, and many rival biological accounts of development then in circulation, scientists suspected that it was just as possible to ''devolve'', to slip back down the evolutionary scale to prior states of development.
One of the first biologists to suggest devolution was
Ray Lankester Sir Edwin Ray Lankester (15 May 1847 – 13 August 1929) was a British zoologist.New International Encyclopaedia. An invertebrate zoologist and evolutionary biologist, he held chairs at University College London and Oxford University. He was th ...
, he explored the possibility that evolution by
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
may in some cases lead to devolution, an example he studied was the regressions in the life cycle of
sea squirts Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer test or "tunic" made of the polysaccharid ...
. Lankester discussed the idea of devolution in his book ''Degeneration: A Chapter in Darwinism'' (1880). He was a critic of progressive evolution, pointing out that higher forms existed in the past which have since degenerated into simpler forms. Lankester argued that "if it was possible to evolve, it was also possible to devolve, and that complex organisms could devolve into simpler forms or animals".
Anton Dohrn Felix Anton Dohrn FRS FRSE (29 December 1840 – 26 September 1909) was a prominent German Darwinist and the founder and first director of the first marine-biological and zoological research station in the world, the Stazione Zoologica in Nap ...
also developed a theory of degenerative evolution based on his studies of
vertebrates Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...
. According to Dohrn many
chordates A chordate ( ) is a bilaterian animal belonging to the phylum Chordata ( ). All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics ( synapomorphies) that distinguish them from ot ...
are degenerated because of their environmental conditions. Dohrn claimed
cyclostomes Cyclostome is a biological term (from the Greek for "round mouth") used in a few different senses: * for the taxon Cyclostomi, which comprises the extant jawless fishes: the hagfish (Myxini) and the lampreys (Petromyzontidae). This was thought for ...
such as
lampreys Lampreys (sometimes inaccurately called lamprey eels) are a group of Agnatha, jawless fish comprising the order (biology), order Petromyzontiformes , sole order in the Class (biology), class Petromyzontida. The adult lamprey is characterize ...
are degenerate fish as there is no evidence their jawless state is an ancestral feature but is the product of environmental adaptation due to
parasitism Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...
. According to Dohrn if cyclostomes would devolve further then they would resemble something like an
Amphioxus The lancelets ( ), also known as amphioxi (: amphioxus ), consist of 32 described species of somewhat fish-like benthic filter feeding chordates in the subphylum Cephalochordata, class Leptocardii, and family Branchiostomatidae. Lancelets div ...
. The historian of biology Peter J. Bowler has written that devolution was taken seriously by proponents of
orthogenesis Orthogenesis, also known as orthogenetic evolution, progressive evolution, evolutionary progress, or progressionism, is an Superseded theories in science, obsolete biological hypothesis that organisms have an innate tendency to evolution, evolve ...
and others in the late 19th century who at this period of time firmly believed that there was a direction in evolution.
Orthogenesis Orthogenesis, also known as orthogenetic evolution, progressive evolution, evolutionary progress, or progressionism, is an Superseded theories in science, obsolete biological hypothesis that organisms have an innate tendency to evolution, evolve ...
was the belief that evolution travels in internally directed trends and levels. The
paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
Alpheus Hyatt Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Hyatt served as the founding president of the American Society of Naturalists from 1883 to 1884 and was the founding editor of the journal '' T ...
discussed devolution in his work, using the concept of ''racial senility'' as the mechanism of devolution. Bowler defines ''racial senility'' as "an evolutionary retreat back to a state resembling that from which it began." Hyatt who studied the
fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
of
invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...
believed that up to a point
ammonoids Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
developed by regular stages up until a specific level but would later due to unfavourable conditions descend back to a previous level, this according to Hyatt was a form of lamarckism as the degeneration was a direct response to external factors. To Hyatt after the level of degeneration the species would then become extinct, according to Hyatt there was a "phase of youth, a phase of maturity, a phase of senility or degeneration foreshadowing the extinction of a type". To Hyatt the devolution was predetermined by internal factors which organisms can neither control or reverse. This idea of all evolutionary branches eventually running out of energy and degenerating into
extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
was a pessimistic view of
evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
and was unpopular amongst many scientists of the time.
Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyology, ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited wit ...
an
ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...
wrote ''Cave vertebrates of America: a study in degenerative evolution'' (1909) in which he concluded that
cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...
evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
was essentially degenerative. The
entomologist Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...
William Morton Wheeler William Morton Wheeler (March 19, 1865 – April 19, 1937) was an American entomologist, myrmecologist and professor at Harvard University. Biography Early life and education William Morton Wheeler was born on March 19, 1865, to parents Juliu ...
and the Lamarckian Ernest MacBride (1866–1940) also advocated degenerative evolution. According to Macbride
invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...
s were actually degenerate
vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...
s, his argument was based on the idea that "crawling on the seabed was inherently less stimulating than swimming in open waters."


Degeneration theory

Johann Friedrich Blumenbach Johann Friedrich Blumenbach (11 May 1752 – 22 January 1840) was a German physician, naturalist, physiologist and anthropologist. He is considered to be a main founder of zoology and anthropology as comparative, scientific disciplines. He has be ...
and other monogenists such as
Georges-Louis Leclerc, Comte de Buffon Georges-Louis Leclerc, Comte de Buffon (; 7 September 1707 – 16 April 1788) was a French Natural history, naturalist, mathematician, and cosmology, cosmologist. He held the position of ''intendant'' (director) at the ''Jardin du Roi'', now ca ...
were believers in the "Degeneration theory" of racial origins. The theory claims that races can degenerate into "primitive" forms. Blumenbach claimed that
Adam and Eve Adam and Eve, according to the creation myth of the Abrahamic religions, were the first man and woman. They are central to the belief that humanity is in essence a single family, with everyone descended from a single pair of original ancestors. ...
were
white White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...
and that other races came about by degeneration from environmental factors such as the sun and poor diet. Buffon believed that the degeneration could be reversed if proper environmental control was taken and that all contemporary forms of man could revert to the original
Caucasian race The Caucasian race (also Caucasoid, Europid, or Europoid) is an Historical race concepts, obsolete racial classification of humans based on a now-disproven theory of biological race. The ''Caucasian race'' was historically regarded as a biologi ...
. Blumenbach claimed Negroid
pigmentation A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go in ...
arose because of the result of the heat of the tropical sun, cold wind caused the tawny colour of the
Eskimos ''Eskimo'' () is a controversial Endonym and exonym, exonym that refers to two closely related Indigenous peoples: Inuit (including the Alaska Native Iñupiat, the Canadian Inuit, and the Greenlandic Inuit) and the Yupik peoples, Yupik (or Sibe ...
and the Chinese were fair skinned compared to the other Asian stocks because they kept mostly in towns protected from environmental factors. According to Blumenbach there are five races all belonging to a single species:
Caucasian Caucasian may refer to: Common meanings *Anything from the Caucasus region or related to it ** Ethnic groups in the Caucasus ** ''Caucasian Exarchate'' (1917–1920), an ecclesiastical exarchate of the Russian Orthodox Church in the Caucasus re ...
, Mongolian,
Ethiopian Ethiopians are the native inhabitants of Ethiopia, as well as the global diaspora of Ethiopia. Ethiopians constitute several component ethnic groups, many of which are closely related to ethnic groups in neighboring Eritrea and other parts of ...
, American and Malay. Blumenbach however stated:
I have allotted the first place to the Caucasian because this stock displays the most beautiful race of men.Emmanuel Chukwudi Eze, Race and the enlightenment: a reader, 1997, p. 79
According to Blumenbach the other races are supposed to have degenerated from the Caucasian ideal stock. Blumenbach denied that his "Degeneration theory" was racist; he also wrote three essays claiming non-white peoples are capable of excelling in arts and sciences in reaction against racialists of his time who believed they couldn't.


In literature and popular culture

Cyril M. Kornbluth's 1951 short story " The Marching Morons" is an example of dysgenic pressure in fiction, describing a man who accidentally ends up in the distant future and discovers that dysgenics has resulted in mass stupidity. Similarly,
Mike Judge Michael Craig Judge (born October 17, 1962) is an American actor, animator, writer, producer, and director. He is best known for being the creator of the animated television series ''Beavis and Butt-Head'' (1993–1997, 2011, 2022–present). He ...
's 2006 film ''
Idiocracy ''Idiocracy'' is a 2006 American science fiction comedy film co-produced and directed by Mike Judge from a screenplay written by Judge and Etan Cohen based on a story written by Judge. The plot follows United States Army librarian Joe Bauers ...
'' has the same premise, with the main character the subject of a military
hibernation Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is mos ...
experiment that goes awry, taking him 500 years into the future. While in "The Marching Morons", civilization is kept afloat by a small group of dedicated geniuses, in ''Idiocracy'',
voluntary childlessness Voluntary childlessness or childfreeness is the active choice not to have children and not to Adoption, adopt children. Use of the word ''childfree'' was first recorded in 1901 and entered common usage among Feminism, feminists during the 1970s. ...
among high-IQ couples leaves only
automated systems Automation describes a wide range of technologies that reduce human intervention in processes, mainly by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machine ...
to fill that role. The 1998 song " Flagpole Sitta" by
Harvey Danger Harvey Danger was an American indie/alternative rock band. It was formed in 1992 in Seattle, Washington, by Aaron Huffman and Jeff J. Lin, who were both journalism students at the University of Washington. Drummer Evan Sult and singer Sean N ...
finds lighthearted humor in dysgenics with the lines "Been around the world and found/That only stupid people are breeding/The cretins cloning and feeding/And I don't even own a tv".
H. G. Wells Herbert George Wells (21 September 1866 – 13 August 1946) was an English writer, prolific in many genres. He wrote more than fifty novels and dozens of short stories. His non-fiction output included works of social commentary, politics, hist ...
' 1895 novel, ''
The Time Machine ''The Time Machine'' is an 1895 dystopian post-apocalyptic science fiction novella by H. G. Wells about a Victorian scientist known as the Time Traveller who travels to the year 802,701. The work is generally credited with the popularizati ...
'', describes a future world where humanity has degenerated into two distinct branches who have their roots in the class distinctions of Wells' day. Both have sub-human intelligence and other putative dysgenic traits. T. J. Bass's novels '' Half Past Human'' and '' The Godwhale'' describe humanity becoming cooperative and "low-maintenance" to the detriment of all other traits. The American new wave band
Devo Devo is an American new wave band from Akron, Ohio, formed in 1973. Their classic line-up consisted of two sets of brothers, the Mothersbaughs ( Mark and Bob) and the Casales (Gerald and Bob), along with Alan Myers. The band had a No. 14 ...
derived both their name and overarching philosophy from the concept of "de-evolution" and used social satire and humor to espouse the idea that humanity had actually regressed over time. According to music critic Steve Huey, the band "adapted the theory to fit their view of American society as a rigid, dichotomized instrument of repression ensuring that its members behaved like clones, marching through life with mechanical, assembly-line precision and no tolerance for ambiguity."
DC Comics DC Comics (originally DC Comics, Inc., and also known simply as DC) is an American comic book publisher owned by DC Entertainment, a subsidiary of Warner Bros. Discovery. DC is an initialism for "Detective Comics", an American comic book seri ...
' ''
Aquaman Aquaman is a superhero appearing in American comic books published by DC Comics. Created by Paul Norris and Mort Weisinger, the character debuted in ''More Fun Comics'' #73 (November 1941). Initially a backup feature in DC's anthology titles ...
'' has one of the seven races of
Atlantis Atlantis () is a fictional island mentioned in Plato's works '' Timaeus'' and ''Critias'' as part of an allegory on the hubris of nations. In the story, Atlantis is described as a naval empire that ruled all Western parts of the known world ...
called The Trench, similar to the
Grindylow In English folklore, Grindylow or Grundylow is a creature in the counties of Yorkshire and Lancashire. The name is thought to be connected to Grendel, a name or term used in ''Beowulf'' and in many Old English charters where it is seen in connect ...
s of British folklore,
Cthulhu Mythos The Cthulhu Mythos is a mythopoeia and a shared fictional universe, originating in the works of American Horror fiction, horror writer H. P. Lovecraft. The term was coined by August Derleth, a contemporary correspondent and protégé of Lovecraft, t ...
' Deep One,
Universal Classic Monsters The Universal Monsters (also known as Universal Classic Monsters and Universal Studios Monsters) is a media franchise comprising various horror film series distributed by Universal Pictures. It consists of different horror creature characters o ...
'
Gill-man The Gill-man, commonly called The Creature from The Black Lagoon, or simply The Creature, is the movie monster of the 1954 black-and-white film ''Creature from the Black Lagoon'' and its two sequels '' Revenge of the Creature'' (1955) and '' Th ...
, and
Fallout Nuclear fallout is residual radioactive material that is created by the reactions producing a nuclear explosion. It is initially present in the radioactive cloud created by the explosion, and "falls out" of the cloud as it is moved by the ...
's Mirelurk. They were regressed to survive in the deepest, darkest places on the bottom of ocean trenches where they hide—hence their name—and are photophobic when in contact with light.
LEGO Lego (, ; ; stylised as LEGO) is a line of plastic construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. Lego consists of variously coloured interlocking plastic bricks made of acrylonitri ...
's 2009 ''
Bionicle Bionicle (stylized all caps) is a discontinued line of Lego construction toys marketed primarily towards 8-to-16-year-olds. The line was launched in 2001, originally as a subsidiary of Lego's Technic series. Over the following decade, it beca ...
'' sets include Glatorian and Agori. One of the six tribes includes The Sand Tribe, which the Glatorian and Agori of that tribe are turned into scorpion-like beasts—the Vorox and the Zesk—by their creators, The Great Beings; whom are also of the same species as Glatorian and Agori.
Kurt Vonnegut Kurt Vonnegut ( ; November 11, 1922 – April 11, 2007) was an American author known for his Satire, satirical and darkly humorous novels. His published work includes fourteen novels, three short-story collections, five plays, and five nonfict ...
's 1985 novel '' Galápagos'' is set a million years in the future, where humans have "devolved" to have much smaller brains.
Robert E. Howard Robert Ervin Howard (January 22, 1906 – June 11, 1936) was an American writer who wrote pulp magazine, pulp fiction in a diverse range of genres. He created the character Conan the Barbarian and is regarded as the father of the sword and sor ...
, in ''
The Hyborian Age "The Hyborian Age" is an essay by American writer Robert E. Howard pertaining to the Hyborian Age, the fictional setting of his stories about Conan the Barbarian, Conan the Cimmerian. It was written in the 1930s but not published during Howard's ...
'', an essay on his
Conan the Barbarian Conan the Barbarian (also known as Conan the Cimmerian) is a fictional sword and sorcery hero created by American author Robert E. Howard (1906–1936) and who debuted in 1932 and went on to appear in a series of fantasy stories published in ''We ...
universe, stated that the Atlanteans devolved into "ape-men", and had once been the Picts (distinct from the actual people; his are closely modeled on Algonquian Native Americans). Similarly,
Helena Blavatsky Helena Petrovna Blavatsky (; – 8 May 1891), often known as Madame Blavatsky, was a Russian-born Mysticism, mystic and writer who emigrated to the United States where she co-founded the Theosophical Society in 1875. She gained an internat ...
, founder of
Theosophy Theosophy is a religious movement established in the United States in the late 19th century. Founded primarily by the Russian Helena Blavatsky and based largely on her writings, it draws heavily from both older European philosophies such as Neop ...
, believed, contrary to standard evolutionary theory, that apes had devolved from humans rather than the opposite, through affected people "putting themselves on the animal level".Blavatsky, Helena (1888), ''The First Message to WQ Judge, General Secretary of the American Section of the Theosophical Society'', pp. 185–187.
Jonathan Swift Jonathan Swift (30 November 1667 – 19 October 1745) was an Anglo-Irish writer, essayist, satirist, and Anglican cleric. In 1713, he became the Dean (Christianity), dean of St Patrick's Cathedral, Dublin, and was given the sobriquet "Dean Swi ...
's 1726 novel ''
Gulliver's Travels ''Gulliver's Travels'', originally titled ''Travels into Several Remote Nations of the World. In Four Parts. By Lemuel Gulliver, First a Surgeon, and then a Captain of Several Ships'', is a 1726 prose satire by the Anglo-Irish writer and clerg ...
'' contains a story about Yahoos, a kind of human-like creature turned into a savage, animal-like the state of society in which the Houyhnhnms—descendants of horses—are the dominant species. H.P. Lovecraft's 1924 short story ''
The Rats in the Walls "The Rats in the Walls" is a short story by American author H. P. Lovecraft. Written in August–September 1923, it was first published in ''Weird Tales'', March 1924. Plot In 1923, an American named Delapore, the last descendant of the De la P ...
'' also describes devolved humans.


References

{{Authority control Creationism Evolutionary biology