martes, julio 08, 2008

NOTHING IN EVOLUTION MAKES SENSE BUT IN THE LIGHT OF BIOLOGY

Inverted Dobzhansky (in Chilean Andes)

This phrase was recently uttered at an evo-devo symposium by MQ Martindale. By turning Dobzhansky's dictum on its head, Martindale was referring to how the study of the development of marine invertebrates is crucial to reconstruct the evolutionary history of metazoa (1). However, this phrase can find unsuspected depths in its resonance, quite beyond the reconstruction of natural history. It reminds us of the big crime that was the elimination of developmental biology from the neodarwinian synthesis (buried in the name of population genetics).
In fact, the actual priority that should be given to organismal biology, including development, continues to evade much mainstream evolutionary biology, which continues to show too much adaptationist-reduccionist nonsense as a result of a doctrinary enthronization of population genetics.
Take the case of Richard Lewontin. He gets close to the truth on many counts but does not acknowledge the centrality of having a theory of organism. Without this, placing the focus on population genetics (his field) will always be misleading: the organism is collapsed between the gene level and the population level. In other words, to get a correct view of evolution Lewontin would have to renounce to population genetics as the basic framework and thus be willing to erase the blackboard for a new starting point. Notice that by erasing the blackboard I do not mean to destroy the achievements of population genetics, denying any of its utility for answering specific questions. It is merely not to consider it as starting point of all evolutionary understanding.
In fact, biology is a larger topic than population genetics, even larger than evolution itself. Yet the absence of a generally accepted theory of organism has led to confuse the branch with the root: thus the vaccum at the roots is not properly acknowledged.
This, however, did not happen to Humberto Maturana upon being asked by a medicine student "what happened at the origin of life, such that we can say that life began?". Suddenly realizing he did not have a theory of organism, Maturana blushed and was only capable of promising the student he would think it over and answer his question next year.
The result, as many chilean and brazilian biologists already know, was the theory of autopoiesis, a theory of the basic organization of the living. A systems perpective providing minimal theoretical terms for understanding exactly what is goig on in organisms, such that they exhibit the properties we observe. This is not a definiton made for evolutionary biology; it is a definition for life, and as such, universal to all biology. This is why the notion of auotopoiesis has proven fruitful in the theoretical discussion of fields of biology that would appear completely dispar, for instance, the study of abiogenesis; inmunology; and neurobiology (not to mention a somewhat distorted use of the term that has become very popular in the social sciences).
And it so happens that the systems perspective of autopoiesis, focused on the organism, has implications for the understanding of evolution, too...

(1): Like myself, Martindale proposes a ctenophore-like ancestor of bilateria: See Vargas and Aboitiz 2005.

17 comentarios:

Emilio Cervantes dijo...

Parece lógico que la poderosa ciencia experimental que es la Biología, con todos sus espectaculares resultados en bioquímica y genética, indique los caminos por los que pueda transcurrir la evolución. Lo contrario suena extraño, si no fuese porque lo hemos oido tan a menudo,.....

Anónimo dijo...

Que frase excelente! como é que ninguém tinha dito isso antes?
hahahaha

PS.: gosto de pensar que a relevância da autopoiese não é explicar o que é vida (a pergunta pelo substantivo que todo mundo faz), mas sim explicar o que vemos como um sistema vivo num processo de conservação em seu viver. Verbos!

abraço, Gustavo

Sanders dijo...

el reduccionismo de la bioquímica y la genética es en part responsable de colapsar el nivel organísmico entre gen y población; se trata de disfrazar la biología de física o química. Ojo con confundirse

Cristian dijo...

Es necesario tener como punto de partida al ser vivo y poder definir sus propiedades, autopoiesis, plasticidad, comportamiento.. etc..

A partir de esto los seres vivos no son solamente entes que sufren los efectos de filtros fenotípicos (=SN) sino que juegan un papel creativo en su cambio ontofilogenetico.

Chico dijo...

Tomei a liberdade de incluir esta imagem rara de Dobzhansky em Chile, El Cristo Redentor del Darwinismo,

Chico dijo...

P.S. Dobzhansky era cristão ortodoxo (era Ucraniano) e acreditava que Deus usou a evolução para criar a diversidade na terra.

Cristian dijo...

Bien mesianica la foto, Wena Chico!

Sanders dijo...

ya que la frase está al revés, me dí la licencia de dar vuelta la imagen de dobzhansky hahaha

Sanders dijo...

de adonde la sacaste, chico?

Chico dijo...

hahaha quedó fantastica!

Saqué de un pre-print de Paul Griffiths:
http://paul.representinggenes.org/publications.html
(el más reciente)

Chico dijo...

"I take the arguments in this paper to be consistent with the claim that the fundamental
identity of the parts and processes studied in experimental biology is given by
homology. Question like ‘which bone is that?’ and ‘which gene is that?’ are answered
by classifying those bones and genes by homology. Thus, for example, the long bones
which support the wing membrane of a bat are homologous to my fingers. This is part
of the answer to the question ‘which bones do bats use to support their wing
membranes?’ The single opsin gene on the X-chromosome of a marmoset is
homologous to both the medium and long-wave opsin genes on my own X
chromosome. This is part of the answer to the question ‘which genes are these ones on
the human X chromosome that allow humans to distinguish colours?’ To identify a
part or process is to identify which parts it corresponds to in other organisms."

Roberto E. Yury Yáñez dijo...

sin evolución la biología es una colección de datos rosas, sin el organismo y su participación en su propio desarrollo (comportamiento, plasticidad como mencionaron) la biología son ecuaciones sin sentido y meras reacciones qcas.

Maturana menciona que una reacción enzimática fuera del contexto de célula es una cuestión qca no biológica, por ejemplo.

Sanders dijo...

Sin la evolución la biología estaría desesperadamente incompleta; sin embargo, los teóricos del darwinismo han puesto a la selección natural y la genética de poblaciones por delante de la adecuada y diligente observación de los datos biológicos relevantes (motivo por el cual meten la pata bochornosamente a cada rato).

para mí no hay nada peor que un marco teórico evolutivo que pone la ideología por sobre los fenómenos....

Sanders dijo...

El problema está en pensar que con la evolución ya toda la biología cobró sentido, sin reconocer el grave vacío que es no contar con una teoría del organismo. Sin una teoría del organismo, la evolución se transforma en un dogma ideológico si se le considera que por sí sola "ya explica" la biología

Roberto E. Yury Yáñez dijo...
Este comentario ha sido eliminado por el autor.
Roberto E. Yury Yáñez dijo...

El fenómeno es lo que el científico describe... las piedras caen como cresta caen es lo que describe el modelo no caen "porque" disminuyen su energía potencial, etc, etc... lo que es tan claro en la física parece NO serlo TANTO en biología y por eso la selección o la genética de poblaciones es constantemente confundida con el fenómeno de que los bichos son "diversos y comunes al mismo tiempo"

Sanders dijo...

el problema está en confundir la rama con la raíz: antes de que pueda ahbr evolución, tiene que haber un ser vivo, un proceso de autopoiesis. La biología es la ciencia grande; la biología evolutiva, el estudio de la evolución de los seres vivos.