Orthogenesis
Encyclopedia
Orthogenesis, orthogenetic evolution, progressive evolution or autogenesis, is the hypothesis
that life
has an innate tendency to evolve
in a unilinear fashion due to some internal or external "driving force". The hypothesis is based on essentialism
and cosmic teleology
and proposes an intrinsic drive which slowly transforms species
. George Gaylord Simpson
(1953) in an attack on orthogenesis called this mechanism "the mysterious inner force". Classic proponents of orthogenesis have rejected the theory of natural selection
as the organising mechanism in evolution
, and theories of speciation
for a rectilinear model of guided evolution acting on discrete species with "essence
s". The term orthogenesis was popularized by Theodor Eimer
, though many of the ideas are much older (Bateson 1909).
. Theodor Eimer
was the first to give the word a definition, he defined orthogenesis as "the general law according to which evolutionary development takes place in a noticeable direction, above all in specialized groups."
Orthogenesis was often related to Neo-Lamarckism; Eimer popularized the concept of orthogenesis in his book Organic Evolution as the Result of the Inheritance of Aquired Characteristics According to the Laws of Organic Growth (1890). In his work Eimer used examples such as the evolution
of the horse
to argue that evolution had proceeded in a regular single direction that was difficult to explain by random variation. To orthogenesis trends in evolution were often nonadaptive and in some cases species
could be lead to extinction
.
Peter J. Bowler
defines orthogenesis as:
According to (Schrepfer, 1983):
Orthogenesis has been described as an "anti-Darwinian" evolutionary theory because of its stance on the Darwinian mechanism of natural selection
. After studying butterfly
coloration Theodor Eimer
published a widely read book on orthogenesis titled On Orthogenesis: And the Impotence of Natural Selection in Species Formation (1898). In the book Eimer claimed there were trends in evolution
with no adaptive significance and thus would be difficult to explain by natural selection. Stephen J. Gould wrote a detailed biography of Eimer. Gould wrote that Eimer was a materialist who rejected any vitalist or teleological approach to orthogenesis and explained that Eimer's criticism of natural selection was common amongst many evolutionists of his generation as they were searching for alternative evolutionary mechanisms as it was believed at the time that natural selection could not create new species
.
, were being proposed. Jean-Baptiste Lamarck
himself accepted the idea, and it had a central role in his theory of inheritance of acquired characteristics, the hypothesized mechanism of which resembled the "mysterious inner force" of orthogenesis.
Other proponents of orthogenesis included Leo S. Berg, philosopher Henri Bergson
and, for a time, the paleontologist Henry Fairfield Osborn
. Orthogenesis was particularly accepted by paleontologists who saw in their fossils a directional change, and in invertebrate paleontology
thought there was a gradual and constant directional change. Those who accepted orthogenesis in this way, however, did not necessarily accept that the mechanism that drove orthogenesis was teleological. In fact, Darwin
himself rarely used the term "evolution" now so commonly used to describe his theory, because in Darwin's time, evolution usually was associated with some sort of progressive process like orthogenesis, and this had been common usage since at least 1647.
The zoologist Charles Otis Whitman
did not believe in Lamarckism
, Darwinism
or mutationism
, instead Whitman was an advocate of orthogenesis. Whitman only wrote one book on orthogenesis which was published nine years after his death in 1919 titled Orthogenetic evolution in pigeons the book was published in a three volume set titled Posthumous Works of Charles Otis Whitman. Stephen Jay Gould
wrote that the book was written "too late, to win any potential influence".
In 1930 the American zoologist Austin Hobart Clark
attempted to modify orthogenesis with his theory of zoogenesis.
in the fossil record, which was non-linear with many complications. The hypothesis was generally abandoned when no mechanism could be found that would account for the process, and the theory of evolution by natural selection became the prevailing theory of evolution. The modern evolutionary synthesis
, in which the genetic
mechanisms of evolution were discovered, refuted the hypothesis for good. As more was understood about these mechanisms it became obvious that there was no possible naturalistic way in which the newly discovered mechanism of heredity
could be far-sighted or have a memory of past trends.
The orthogenetic hypothesis, however, died hard. Even Darwin was at first not opposed to orthogenic thinking, as this quote from the 1911 Encyclopedia Britannica demonstrates:
A few hung on to the orthogenesis hypothesis as late as the 1950s by claiming that the processes of macroevolution
, the long term trends in evolution, were distinct from the processes of microevolution
(genetic variation
and natural selection
) which were by then well understood and it was known they could not behave in an orthogenetic manner. Teilhard de Chardin, a Jesuit paleontologist, in The Phenomenon of Man
(a book influential among non-scientists that was published four years after his death in 1959) argued for evolution aiming for the "Omega Point
", while putting man at the center of the universe
and accounting for original sin
(Dennett 1995, von Kitzing 1998). The term Chardin used for this was "directed additivity". This form of orthogenesis has now also been abandoned as more about evolutionary processes has been discovered (Wilkins 1997).
The refutation of orthogenesis had some ramifications in the field of philosophy
, as it refuted the idea of teleology as first postulated by Aristotle
and accepted by Immanuel Kant
, who had greatly influenced many scientists. Before the scientific and philosophical revolution that began with Charles Darwin
's ideas, the prevailing philosophy was that the world was teleological and purposeful, and that science was the study of God
's creation. The refutation of these concepts have led to a shift in what science and scientists are perceived to be.
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
that life
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...
has an innate tendency to evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
in a unilinear fashion due to some internal or external "driving force". The hypothesis is based on essentialism
Essentialism
In philosophy, essentialism is the view that, for any specific kind of entity, there is a set of characteristics or properties all of which any entity of that kind must possess. Therefore all things can be precisely defined or described...
and cosmic teleology
Teleology
A teleology is any philosophical account which holds that final causes exist in nature, meaning that design and purpose analogous to that found in human actions are inherent also in the rest of nature. The word comes from the Greek τέλος, telos; root: τελε-, "end, purpose...
and proposes an intrinsic drive which slowly transforms species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. George Gaylord Simpson
George Gaylord Simpson
George Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...
(1953) in an attack on orthogenesis called this mechanism "the mysterious inner force". Classic proponents of orthogenesis have rejected the theory of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
as the organising mechanism in evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
, and theories of speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
for a rectilinear model of guided evolution acting on discrete species with "essence
Essence
In philosophy, essence is the attribute or set of attributes that make an object or substance what it fundamentally is, and which it has by necessity, and without which it loses its identity. Essence is contrasted with accident: a property that the object or substance has contingently, without...
s". The term orthogenesis was popularized by Theodor Eimer
Theodor Eimer
Gustav Heinrich Theodor Eimer was a German zoologist.Eimer was born in Zurich. After spending his junior faculty years as prosector at Julius-Maximillian's University in Würzburg, he became in 1875 a professor of zoology and comparative anatomy at the University of Tübingen.He is credited with...
, though many of the ideas are much older (Bateson 1909).
Definition
Orthogenesis was a term first used by the biologist Wilhelm HaackeWilhelm Haacke
Johann Wilhelm Haacke was a German zoologist born in Clenze, Lower Saxony.He studied zoology at the University of Jena, earning his doctorate in 1878. Afterwards he worked as an assistant at the Universities of Jena and Kiel...
. Theodor Eimer
Theodor Eimer
Gustav Heinrich Theodor Eimer was a German zoologist.Eimer was born in Zurich. After spending his junior faculty years as prosector at Julius-Maximillian's University in Würzburg, he became in 1875 a professor of zoology and comparative anatomy at the University of Tübingen.He is credited with...
was the first to give the word a definition, he defined orthogenesis as "the general law according to which evolutionary development takes place in a noticeable direction, above all in specialized groups."
Orthogenesis was often related to Neo-Lamarckism; Eimer popularized the concept of orthogenesis in his book Organic Evolution as the Result of the Inheritance of Aquired Characteristics According to the Laws of Organic Growth (1890). In his work Eimer used examples such as the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
of the horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
to argue that evolution had proceeded in a regular single direction that was difficult to explain by random variation. To orthogenesis trends in evolution were often nonadaptive and in some cases species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
could be lead to extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
.
Peter J. Bowler
Peter J. Bowler
Peter J. Bowler is a historian of biology who has written extensively on the history of evolutionary thought, the history of the environmental sciences, and on the history of genetics. His 1984 book, Evolution: The History of an Idea is a standard textbook on the history of evolution, and was...
defines orthogenesis as:
Literally, the term means evolution in a straight line, generally assumed to be evolution that is held to a regular course by forces internal to the organism. Orthogenesis assumes that variation is not random but is directed towards fixed goals. Selection is thus powerless, and the species is carried automatically in the direction marked out by internal factors controlling variation.
According to (Schrepfer, 1983):
Orthogenesis meant literally "straight origins", or "straight line evolution". The term varied in meaning from the overtly vitalistic and theological to the mechanical. It ranged from theories of mystical forces to mere descriptions of a general trend in development due to natural limitations of either the germinal material or the environment... By 1910, however most who subscribed to orthogenesis hypothesized some physical rather than metaphysical determinant of orderly change.
Orthogenesis has been described as an "anti-Darwinian" evolutionary theory because of its stance on the Darwinian mechanism of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
. After studying butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
coloration Theodor Eimer
Theodor Eimer
Gustav Heinrich Theodor Eimer was a German zoologist.Eimer was born in Zurich. After spending his junior faculty years as prosector at Julius-Maximillian's University in Würzburg, he became in 1875 a professor of zoology and comparative anatomy at the University of Tübingen.He is credited with...
published a widely read book on orthogenesis titled On Orthogenesis: And the Impotence of Natural Selection in Species Formation (1898). In the book Eimer claimed there were trends in evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
with no adaptive significance and thus would be difficult to explain by natural selection. Stephen J. Gould wrote a detailed biography of Eimer. Gould wrote that Eimer was a materialist who rejected any vitalist or teleological approach to orthogenesis and explained that Eimer's criticism of natural selection was common amongst many evolutionists of his generation as they were searching for alternative evolutionary mechanisms as it was believed at the time that natural selection could not create new species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
.
Origins
The orthogenesis hypothesis had a significant following in the 19th century when a number of evolutionary mechanisms, such as LamarckismLamarckism
Lamarckism is the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring . It is named after the French biologist Jean-Baptiste Lamarck , who incorporated the action of soft inheritance into his evolutionary theories...
, were being proposed. Jean-Baptiste Lamarck
Jean-Baptiste Lamarck
Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often known simply as Lamarck, was a French naturalist...
himself accepted the idea, and it had a central role in his theory of inheritance of acquired characteristics, the hypothesized mechanism of which resembled the "mysterious inner force" of orthogenesis.
Other proponents of orthogenesis included Leo S. Berg, philosopher Henri Bergson
Henri Bergson
Henri-Louis Bergson was a major French philosopher, influential especially in the first half of the 20th century. Bergson convinced many thinkers that immediate experience and intuition are more significant than rationalism and science for understanding reality.He was awarded the 1927 Nobel Prize...
and, for a time, the paleontologist Henry Fairfield Osborn
Henry Fairfield Osborn
Henry Fairfield Osborn, Sr. ForMemRS was an American geologist, paleontologist, and eugenicist.-Early life and career:...
. Orthogenesis was particularly accepted by paleontologists who saw in their fossils a directional change, and in invertebrate paleontology
Invertebrate paleontology
Invertebrate paleontology is sometimes described as Invertebrate paleozoology or Invertebrate paleobiology....
thought there was a gradual and constant directional change. Those who accepted orthogenesis in this way, however, did not necessarily accept that the mechanism that drove orthogenesis was teleological. In fact, Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
himself rarely used the term "evolution" now so commonly used to describe his theory, because in Darwin's time, evolution usually was associated with some sort of progressive process like orthogenesis, and this had been common usage since at least 1647.
The zoologist Charles Otis Whitman
Charles Otis Whitman
-External links:***-Notes:...
did not believe in Lamarckism
Lamarckism
Lamarckism is the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring . It is named after the French biologist Jean-Baptiste Lamarck , who incorporated the action of soft inheritance into his evolutionary theories...
, Darwinism
Darwinism
Darwinism is a set of movements and concepts related to ideas of transmutation of species or of evolution, including some ideas with no connection to the work of Charles Darwin....
or mutationism
Mutationism
Mutationism refers to the theory emphasizing mutation as a creative principle and source of discontinuity in evolutionary change, particularly associated with the founders of modern genetics....
, instead Whitman was an advocate of orthogenesis. Whitman only wrote one book on orthogenesis which was published nine years after his death in 1919 titled Orthogenetic evolution in pigeons the book was published in a three volume set titled Posthumous Works of Charles Otis Whitman. Stephen Jay Gould
Stephen Jay Gould
Stephen Jay Gould was an American paleontologist, evolutionary biologist, and historian of science. He was also one of the most influential and widely read writers of popular science of his generation....
wrote that the book was written "too late, to win any potential influence".
In 1930 the American zoologist Austin Hobart Clark
Austin Hobart Clark
Austin Hobart Clark was an American zoologist. He was born in Wellesley, Massachusetts and died in Washington, D.C...
attempted to modify orthogenesis with his theory of zoogenesis.
Comparison of Theories
| Darwinism | Orthogenesis | Lamarckism | |
| Mechanism | 1. Short-sighted Natural Selection Natural selection Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution.... sorting random genetic variation Genetic variation Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the “raw material” for natural selection. Genetic variation is brought about by mutation, a change in a chemical structure of a gene. Polyploidy is an... , no other guidance or aim. 2. Selected traits are adaptive, i.e. have some survival value. |
1. Driven by some internal mechanism, but not towards a goal. 2. Natural selection unimportant. 3. Characters produced may be totally non-adaptive, i.e. have no survival value. |
1. Intrinsic drive towards perfection 2. Inheritance of acquired characteristics (both are Lamarckian principles) 3. Natural selection adopted by some in latter years. |
| Common descent Common descent In evolutionary biology, a group of organisms share common descent if they have a common ancestor. There is strong quantitative support for the theory that all living organisms on Earth are descended from a common ancestor.... |
Yes New species coming into existence by speciation Speciation Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages... events. |
No Speciation rejected or considered unimportant in long term trends; spontaneous generation Spontaneous generation Spontaneous generation or Equivocal generation is an obsolete principle regarding the origin of life from inanimate matter, which held that this process was a commonplace and everyday occurrence, as distinguished from univocal generation, or reproduction from parent... of new species resulting in parallel evolution. |
Depends upon source quoted Signs that species shared a common ancestor were detected before Darwin, but in absence of a mechanism some still rejected the idea. |
| Status | Prevailing in modified form as modern evolutionary synthesis Modern evolutionary synthesis The modern evolutionary synthesis is a union of ideas from several biological specialties which provides a widely accepted account of evolution... . |
Refuted by Charles Darwin Charles Darwin Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory... 's Origin of Species and the modern evolutionary synthesis Modern evolutionary synthesis The modern evolutionary synthesis is a union of ideas from several biological specialties which provides a widely accepted account of evolution... . |
Declined after the Origin, though the mechanism was not refuted until the modern evolutionary synthesis Modern evolutionary synthesis The modern evolutionary synthesis is a union of ideas from several biological specialties which provides a widely accepted account of evolution... in which it was established that the mechanism does not exist. |
Collapse of the hypothesis
The orthogenesis hypothesis began to collapse when it became clear that it could not explain the patterns found by paleontologistsPaleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
in the fossil record, which was non-linear with many complications. The hypothesis was generally abandoned when no mechanism could be found that would account for the process, and the theory of evolution by natural selection became the prevailing theory of evolution. The modern evolutionary synthesis
Modern evolutionary synthesis
The modern evolutionary synthesis is a union of ideas from several biological specialties which provides a widely accepted account of evolution...
, in which the genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
mechanisms of evolution were discovered, refuted the hypothesis for good. As more was understood about these mechanisms it became obvious that there was no possible naturalistic way in which the newly discovered mechanism of heredity
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
could be far-sighted or have a memory of past trends.
The orthogenetic hypothesis, however, died hard. Even Darwin was at first not opposed to orthogenic thinking, as this quote from the 1911 Encyclopedia Britannica demonstrates:
A few hung on to the orthogenesis hypothesis as late as the 1950s by claiming that the processes of macroevolution
Macroevolution
Macroevolution is evolution on a scale of separated gene pools. Macroevolutionary studies focus on change that occurs at or above the level of species, in contrast with microevolution, which refers to smaller evolutionary changes within a species or population.The process of speciation may fall...
, the long term trends in evolution, were distinct from the processes of microevolution
Microevolution
Microevolution is the changes in allele frequencies that occur over time within a population. This change is due to four different processes: mutation, selection , gene flow, and genetic drift....
(genetic variation
Genetic variation
Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the “raw material” for natural selection. Genetic variation is brought about by mutation, a change in a chemical structure of a gene. Polyploidy is an...
and natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
) which were by then well understood and it was known they could not behave in an orthogenetic manner. Teilhard de Chardin, a Jesuit paleontologist, in The Phenomenon of Man
The Phenomenon of Man
The Phenomenon of Man is a book written by French philosopher, paleontologist and Jesuit priest Pierre Teilhard de Chardin. In this work, Teilhard describes evolution as a process that leads to increasing complexity, culminating in the unification of consciousness.The book was finished in the...
(a book influential among non-scientists that was published four years after his death in 1959) argued for evolution aiming for the "Omega Point
Omega point
Omega Point is a term coined by the French Jesuit Pierre Teilhard de Chardin to describe a maximum level of complexity and consciousness towards which he believed the universe was evolving....
", while putting man at the center of the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
and accounting for original sin
Original sin
Original sin is, according to a Christian theological doctrine, humanity's state of sin resulting from the Fall of Man. This condition has been characterized in many ways, ranging from something as insignificant as a slight deficiency, or a tendency toward sin yet without collective guilt, referred...
(Dennett 1995, von Kitzing 1998). The term Chardin used for this was "directed additivity". This form of orthogenesis has now also been abandoned as more about evolutionary processes has been discovered (Wilkins 1997).
The refutation of orthogenesis had some ramifications in the field of philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
, as it refuted the idea of teleology as first postulated by Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
and accepted by Immanuel Kant
Immanuel Kant
Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....
, who had greatly influenced many scientists. Before the scientific and philosophical revolution that began with Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
's ideas, the prevailing philosophy was that the world was teleological and purposeful, and that science was the study of God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....
's creation. The refutation of these concepts have led to a shift in what science and scientists are perceived to be.
Modern co-opted usage
Though linear teleological evolution has been refuted, it is not true that evolution never proceeds in a linear way, reinforcing characteristics, in certain lineages at times, for example, during a period of slow, sustained environmental change, but such examples are entirely consistent with the modern neo-Darwinian theory of evolution. These examples have sometimes been referred to as orthoselection (e.g. by Jacobs et al. 1995; Ranganath & Hägele, 1981) but are not strictly orthogenetic, and simply appear as linear and constant changes because of environmental and molecular constraints on the direction of change.See also
- Facilitated variationFacilitated variationFacilitated variation is a new theory that has been presented by Marc W. Kirschner, a professor and chair at the Department of Systems Biology, Harvard Medical School, and John C. Gerhart, a professor at the Graduate School, University of California, Berkeley....
- Evolution of complexityEvolution of complexityThe evolution of biological complexity is an 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 biology, with properties such as gene content, the number of...
- Eclipse of Darwinism
- History of evolutionary thoughtHistory of evolutionary thoughtEvolutionary thought, the conception that species change over time, has roots in antiquity, in the ideas of the ancient Greeks, Romans, and Chinese as well as in medieval Islamic science...
- Law of Complexity/ConsciousnessLaw of Complexity/ConsciousnessThe Law of Complexity/Consciousness is the tendency in matter to become more complex over time and at the same time to become more conscious. The law was first formulated by Jesuit priest and paleontologist Pierre Teilhard de Chardin....
Sources
- Bateson, WilliamWilliam BatesonWilliam Bateson was an English geneticist and a Fellow of St. John's College, Cambridge...
, 1909. Heredity and variation in modern lights, in Darwin and Modern Science (A.C. Seward ed.). Cambridge University Press. Chapter V. E-book. - Dennett, DanielDaniel DennettDaniel Clement Dennett is an American philosopher, writer and cognitive scientist whose research centers on the philosophy of mind, philosophy of science and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. He is currently the Co-director of...
, 1995. Darwin's Dangerous IdeaDarwin's Dangerous IdeaDarwin's Dangerous Idea: Evolution and the Meanings of Life is a book by Daniel Dennett which argues that Darwinian processes are the central organizing force that gives rise to complexity...
. Simon & Schuster. - Huxley, JulianJulian HuxleySir Julian Sorell Huxley FRS was an English evolutionary biologist, humanist and internationalist. He was a proponent of natural selection, and a leading figure in the mid-twentieth century evolutionary synthesis...
, 1942. The Modern Evolutionary Synthesis, London: George Allen and Unwin. - Jacobs, Susan C., Allan Larson & James M. Cheverud, 1995. Phylogenetic Relationships and Orthogenetic Evolution of Coat Color Among Tamarins (Genus Saguinus). Syst. Biol. 44(4):515—532, Abstract.
- Mayr, ErnstErnst MayrErnst Walter Mayr was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, historian of science, and naturalist...
, 2002. What Evolution Is, London: Weidenfeld and Nicolson. - Simpson, George G.George Gaylord SimpsonGeorge Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...
, 1957. Life Of The Past: Introduction to Paleontology. Yale University Press, p.119. - Wilkins, John, 1997. What is macroevolution?. TalkOrigins ArchiveTalkOrigins ArchiveThe TalkOrigins Archive is a website that presents mainstream science perspectives on the antievolution claims of young-earth, old-earth, and "intelligent design" creationists...
http://www.talkorigins.org/faqs/macroevolution.html (14:08 UTC, Oct 13 2004) - Ranganath, H. A., & Hägel, K, 1981. Karyotypic orthoselection in Drosophila. Natur Wissenschaften. 68(10):527-528, http://www.springerlink.com/content/pw151ll371rt47j0/.