Αναρτήθηκε από: basileios | Ιανουαρίου 2, 2009

Darwin Year

Darwin Year is officially here. 200 years from the birth of Charles Drawin on 1809 and 150 years from the publication of The Origin of Species. I will be taking part in this years celebrations by a) reading The Structure of Evolutionary Theory b) commenting on this weblog and c) writing a novel that has to do with biology and ecology. All three are difficult projects that will take me down very ‘dangerous’ roads (concverning my time and the rest of my life). But i hope they will all three finish within 2009.

Happy New Darwin Year!

Αναρτήθηκε από: basileios | Ιουλίου 29, 2008

…and we are back.

It has been a long break, but things have been quite hectic round here. Reading and commenting has been abandoned temporarily but I am officially back to reading The Structure of Evolutionary Theory and I will start posting my thoughts soon enough.

Αναρτήθηκε από: basileios | Αύγουστος 20, 2007

A comment on Lamarckian evolution

After reading the chapter on Lamarck and the two-factor theory I feel that as Gould comments that ‘soft’ – ‘lamarckian’ inheritence of characteristics that are acquired during ones lifetime can be inherited to the next generation was in a sense folk – wisdom at the time, I feel as if the misconception that most people have today about the idea of evolution is more lamarckian that darwininan, even in the hierearchy, steady state and evolution point of view. In a sense this is natural. We do know that science is seldom common sensical and Lamarch is closer to common sense than Darwin is.

Αναρτήθηκε από: basileios | Αύγουστος 20, 2007

Lamarck’s Continuous Spontaneous Generation

The continuous spontaneous generation of species in order for them to be pushed slowly up the evolution ladder as described in page 180 reminds me to the Hoyle steady state cosmology in which space is expanding and galaxies are evolving (moving up the ladder) but spontaneously matter is created in the gaps that are left by the expansion / evolution…

Αναρτήθηκε από: basileios | Ιουλίου 31, 2007

Lamarck, The Structuralism to Functionalism Shift

Lamarck and the general aura of his ideas is somewhat ridiculed these days (if not during his time as well). The main concept of the Lamarckian hypothesis is that the ‘will’ of organisms is passed on to future generations. Funny as this may sound the evolutionarty context under which this idea is important displays an important shift from the popular ‘strucuralism’ of the era (‘a wing is made in a way that allows the bird to fly’) to a functionalistic principle in which evolution is governed by ‘function’ and subsequently adaptation. Under this perspective changes in the environment come first, ‘will’ of organisms follows and leads to evolution.

In a sense quite neat…

Αναρτήθηκε από: basileios | Ιουλίου 25, 2007

Natural Selection and Gradualism

Selection becomes creative only if it can impart direction to evolution by superintending the slow and staedy accumulation of favored subsets from an isotropic pool of variation. If gradualism does not accompany this process of change, selection must relinquish this creative role and Darwinism then fails as a creative source of evolutionary novelty.

page 149

Αναρτήθηκε από: basileios | Ιουλίου 19, 2007

Natural Selection as a Positive Force

Another intersting point brought out in page 140 is the fact that natural selection as an idea was there a long time before darwin, but it was envisaged as a ‘negative’ evolution force: A mechanism that eliminates the weak and negative from a population and selects the strong and fit. Darwin’s breakthrough was to use this mechanism as a ‘positive’, ‘creative’, ‘progressive’ element that guides the full states of evolution.

However, in order for this to apply there are other assumptions that have to be bundled together in the theory (like herdeity, producing more offspring than ‘necessary’ etc.).

Αναρτήθηκε από: basileios | Ιουλίου 17, 2007

The Level of Natural Selection

An interesting point that was unnoticed – for me – until now is the level on which natural selection works. Darwin chooses to follow as the crucial level of natural selection the organism, the lowest available to him level, and tries to defend this choice against the possibility of selection working at higher organizational levels (group selection).

A bit of research on the internet on this very intersting matter has managed to confuse me even more as till now I was quite happy to accept the Dawkins popularized idea of gene selection, (which Stephen jay Gould dismisses due to ‘contradictions’ in page 136) and on the other hand I always found the sociobiology and group selection idea quite natural in some situations.

Gould mentions briefly (and probably will expand later on) that he is a proponent of a multilevel hierarchical natural selection. Although i am not really that clear on how thsi theory works my initial thinking is that this is probably close to ‘common sense’ as it can possibly be. If I have to guess in this I would say that the level of evolution depends on the communication capacity of the individual members. Species that are able to communicate (in one way or another) and create social communities are bound to have some level of natural selection working on the community itself.

Αναρτήθηκε από: basileios | Ιουλίου 12, 2007

A scientific revolution in context

A preconception of mine when I first started reading The Structure of Evolutionary theory was that natural selection as a scientific revolution (in the Kuhnian sense) was the first of the series of scientific (and cultural) revolutions that followed 50 years later and in a sense it could have acted as a sperm for all the things that followed a few years later.

I am not so clear about this anymore.

I was glad that Stephen Jay Gould stresses the cultural and social substratum in any kind of scientific revolution (page 121) but the link to Adam Smith (via a reference to an acquaintance of mine Silvan Schweber) for a chain of events that have led to natural selection via the laissaiz-fair economic principles makes me feel that Darwin’s revolution is not an ‘early’ revolution, but a ‘late’ one, following the changes in mechanistic thinking all over Europe that had started with Newton a couple of centuries earlier.

Actually, it is quite interesting anyway that none of the revolutions that followed took place in the ‘status quo’ of the victorian empire, but needed the turmoils of Europe to take place.

Αναρτήθηκε από: basileios | Ιουλίου 11, 2007

Galapagos

Galapagos

I have encountered so often the story that Darwin used the Galapagos islands in the Origin of Species as a a mechanism to show diversity and natural selection within a rather secluded part of the word that it was quite a standard for me. I can even remember reading in biology books that Darwin found species totally different from island to island thus demonstrating evolution in action.

The fact is that Darwin never mentioned such an argument in the Origin of Species.

The amazing thing is that Darwin used the Galapagos in entirely different – and more cunning – argument that has to do with the fact that the species found in the Galapagos show a definite relation and affinity with the species found in South America. So far this sounds natural, one would expect to see related species in close geographical areas. The crux is though that although this affinity and resemblance is present the climate, conditions and state of the Galapagos islands is totally different from that found in South America.

In other words the argument does not have to do with diversity but it is an example of affinity which demonstrates common ancestors which have led via the evolution to different (morphological and actual) species due to the very different conditions in South America and the Galapagos.

(page 115)

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