Structuralism (biology)
Encyclopedia
Biological or process structuralism is a school of biological thought that deals with the law-like behaviour of the structure of organism
s and how it can change.
Structuralists tend to emphasise that organisms are wholes
, and therefore that change in one part must necessarily take into account the inter-connected nature of the entire organism. Whilst structuralists are not necessarily anti-Darwinian
, the laws of biological structure are viewed as independent and ahistorical accounts that are not necessarily tied to any particular mechanism of change. A structuralist might thus hold that Darwinian natural selection
might be the driving force behind how structures change, but nevertheless be committed to an extra layer of explanation of how particular structures come into being and are maintained.
Typical structuralist concerns might be self-organisation, the idea that complex structure emerges out of the dynamic interaction of molecule
s, without the resultant structure having necessarily been selected for in all its details. For example, the patterning of fingerprint
s or the stripes of zebra
s might emerge through simple rules of diffusion
, and the resulting unique structure need not have been selected for in its finest details. Structuralists look for very general rules that govern organisms as a whole, and not just particular narratives that explain the origin or maintenance of particular structures. The interplay between structural laws and adaptation thus govern the degree to which an adaptationist
account can fully explain why a particular organism looks as it does.
in understanding biological structure. For example, Muller and Newman have proposed that physical laws of structure govern the genesis of major diversifications (such as in the Cambrian
explosion) with successful structures co-opting genetic generative mechanisms later. Such views can be construed as anti-adaptionist as they insist that selection and adaptation can only work on structure that is presented to them, and not generate the structure in the first place. Again, the incompleteness of natural selection in providing a complete account of biological form is implied. As a result, structuralism has come under assault from classical Neodarwinists such as Maynard-Smith
for, in effect, introducing a metaphysical level of biological explanation, arguing that the locus of the extra laws is far from clear.
References
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s and how it can change.
Structuralists tend to emphasise that organisms are wholes
Holism
Holism is the idea that all the properties of a given system cannot be determined or explained by its component parts alone...
, and therefore that change in one part must necessarily take into account the inter-connected nature of the entire organism. Whilst structuralists are not necessarily anti-Darwinian
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....
, the laws of biological structure are viewed as independent and ahistorical accounts that are not necessarily tied to any particular mechanism of change. A structuralist might thus hold that Darwinian 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....
might be the driving force behind how structures change, but nevertheless be committed to an extra layer of explanation of how particular structures come into being and are maintained.
Typical structuralist concerns might be self-organisation, the idea that complex structure emerges out of the dynamic interaction of molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s, without the resultant structure having necessarily been selected for in all its details. For example, the patterning of fingerprint
Fingerprint
A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. In a wider use of the term, fingerprints are the traces of an impression from the friction ridges of any part of a human hand. A print from the foot can also leave an impression of friction ridges...
s or the stripes of zebra
Zebra
Zebras are several species of African equids united by their distinctive black and white stripes. Their stripes come in different patterns unique to each individual. They are generally social animals that live in small harems to large herds...
s might emerge through simple rules of diffusion
Diffusion
Molecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
, and the resulting unique structure need not have been selected for in its finest details. Structuralists look for very general rules that govern organisms as a whole, and not just particular narratives that explain the origin or maintenance of particular structures. The interplay between structural laws and adaptation thus govern the degree to which an adaptationist
Adaptationism
Adaptationism is a set of methods in the evolutionary sciences for distinguishing the products of adaptation from traits that arise through other processes. It is employed in fields such as ethology and evolutionary psychology that are concerned with identifying adaptations...
account can fully explain why a particular organism looks as it does.
Structuralism and boundary conditions
Given the above account, a fruitful way of thinking about structuralism is as an attempt to provide a set of boundary conditions, governed by the physical, mechanical and chemical nature of matter, within which all types of biological change, including Darwinian evolution, must take place. These boundary conditions exist at a variety of levels of organisation. For example, dynamic molecular interactions might provide boundary conditions to various types of pattern formation; or the analysis of functional morphology might explain why certain structures (e.g. the vertebrate backbone) have remained relatively stable for tens or hundreds of millions of years. Typically, structuralism is anti-reductionist, in that these different levels of explanation cannot always be reduced to lower ones. For example, a structuralist might agree with the classical view of the Neodarwinian synthesis that changes in gene fequencies in populations lie behind all evolutionary change, but would argue that, in addition, other rules governing how structures change are required to come to a full account of how diversity comes about.Structuralism and genes
Extreme structuralists tend to downplay the importance of the geneGene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
in understanding biological structure. For example, Muller and Newman have proposed that physical laws of structure govern the genesis of major diversifications (such as in the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
explosion) with successful structures co-opting genetic generative mechanisms later. Such views can be construed as anti-adaptionist as they insist that selection and adaptation can only work on structure that is presented to them, and not generate the structure in the first place. Again, the incompleteness of natural selection in providing a complete account of biological form is implied. As a result, structuralism has come under assault from classical Neodarwinists such as Maynard-Smith
John Maynard Smith
John Maynard Smith,His surname was Maynard Smith, not Smith, nor was it hyphenated. F.R.S. was a British theoretical evolutionary biologist and geneticist. Originally an aeronautical engineer during the Second World War, he took a second degree in genetics under the well-known biologist J.B.S....
for, in effect, introducing a metaphysical level of biological explanation, arguing that the locus of the extra laws is far from clear.
Constraint and structuralism
Gunter Wagner and others have argued that without at least some sort of structuralist background in the form of the idea of constraint there would not even be the possibility of Darwinian evolution. In effect, without the solidity given to morphological characters that the laws governing their evolution impart to them, they would dissolve and not be available for subsequent modification. Such views would probably be highly controversial if it were not for the fact that there have been rather limited contacts between mainstream evolutionary theorists and the more esoteric ideas represented by various structuralists. However, the field of Evo-devo is providing an arena within which these ideas are being examined more carefully by a variety of evolutionary thinkers. It is thus likely that more intense examination of structuralist views will lead to them being either more forcibly rejected by mainstream evolutionary biology, or to a more fruitful engagement and integration of at least some of them into future general accounts of structure and evolution.Assessment
While it is convenient to think of structuralists as emphasising "form" over "function", and thus being inherently anti-adaptionist, this simplicity hardly does justice to the complex interactions between the study of form per se and Neo-darwinian evolution. Some structuralists undoubtedly see the primacy of the laws of structure as being so important that the effects of selection and adaptation must be restricted to rather minor "fine-tuning" with little real relevance to the origin of form. Nevertheless, the true importance of structuralism - if any - must await the further examination and integration of this rather heterodox approach to biology before a full assessment is possible.Well-known structuralists
Like all biological fields, structuralism encompasses a broad range of thought, but the scientists listed below must be considered to have at least some structuralist inclinations:- Michael DentonMichael DentonMichael John Denton is a British-Australian author and biochemist. In 1973, Denton received his PhD in Biochemistry from King's College London.-Biography:...
; - Stephen Jay GouldStephen Jay GouldStephen 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....
; - Brian GoodwinBrian GoodwinBrian Carey Goodwin was a Canadian mathematician and biologist, a Professor Emeritus at the Open University and a key founder of the field of theoretical biology.He made key contributions to the foundations of biomathematics, complex systems and generative models in developmental biology...
; - Wolfgang Friedrich Gutmann;
- Mae-Wan HoMae-Wan HoMae-Wan Ho is a geneticist known for her critical views on genetic engineering. Ho has authored or co-authored a number of publications, including 10 books, such as The Rainbow and the Worm, the Physics of Organisms , Genetic Engineering: Dream or Nightmare? , and Living with the Fluid Genome...
; - Stuart KauffmanStuart KauffmanStuart Alan Kauffman is an American theoretical biologist and complex systems researcher concerning the origin of life on Earth...
; - David LambertDavid LambertDavid Lambert may refer to:*Dave Lambert , lyricist, singer and originator of vocalese; best known as member of Lambert, Hendricks & Ross...
; - Rupert RiedlRupert RiedlRupert Riedl was an Austrian zoologist who made contributions in the fields of:* Marine biology* Morphology* Theory of evolution * Evolutionary Epistemology* Environment and society...
; - Peter SaundersPeter SaundersPete or Peter Saunders may refer to:* Peter Gordon Saunders, Australian social researcher* Peter Robert Saunders, Australian social researcher* Peter Saunders , English theatre impresario* Pete Saunders , musician...
; - Adolf SeilacherAdolf SeilacherAdolf "Dolf" Seilacher is a German palaeontologist who has made major contributions to evolutionary and ecological palaeobiology in a career stretching over 60 years. He won the Crafoord Prize in 1992, the Paleontological Society Medal in 1994 and the Palaeontological Association's Lapworth Medal...
;
References