Curso de Actualizacióna profesores de la ENP

7 de febrero, 2004Centro de Investigacion sobre Fijacion de Nitrogeno, UNAM,

Cuernavaca

Mapeo del genotipo al fenotipo y del fenotipo al genotipo.

A. Trajectory.

“El precio de la metafora es vigilancia eterna”

Rosenblueth and Wiener.

La metafora de la maquina es central en la ciencia natural. De alli el valor a los

mecanismos

La vision Laplaciana del universo implica concebir a la naturaleza con perspectiva

ingenieril.

Organisms are viewed as machines, BUT:

A. Organisms evolve. History of machines is irrelevant to their functioning.

B. Organisms are generated by differentiation and development. However, a machine can be built in several ways.

A high interaction of the organisms with its milieu differs (at least quantitatively) from the functioning of machines.

Artificial Intelligence. A Branch of Engineering

That part of engineering devoted to solving problems.

A problem by definition has a defined “final state”

Problems are classified into classes.

Natural Selection is one mechanism among others:

Genetic drift, makes changes without particular direction.Arbitrary properties may come from common origin (i.e. l-aacids; HTH position in proteins).Structural and dynamical properties may come from physical properties of biological systems. The example of a flame. D’Arcy Thompson. It is easy to construct just-so-stories.

The “panglossian” paradigm:

Everything is made for a purpose. Even the earhquake in Lisboa (Candide, Voltaire).

It is easy to construct just-so-stories. And this includes sociobiology.

Remember programs of animal planet. where consistency seems to be enough.

Why do animals play? Why are they beautiful? Is every diversity in life optimized?(i.e. human sacrifices by aztecs)

Complexity is hard to explain by cumulative natural selection:

A fraction of the eye or a wing offers no selective advantage

An alternative explanation:

Recruitment of an already existing structure or exaptation: front legs for wings, jawbones of reptiles for ear-bones in mammals; motor area for human speech.

We tend to forget that the first “environment” the organism has to confront is its own structure !

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

La erosión como análoga del tiempo.Las formas dependen de su estructura interna

Evolution and Adaptation as “problem solving”

Prospective vs retrospective trajectories: There is no natural analog to a knowledge of a final state.

Who is first the organism or the environment? Just as there is no organism without environment, there is no environment without organism.

Organisms affect and modify their environment. This is why they seem so well adapted to it.

A better analogy: Organisms construct their environment.