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Lamarckism and the Honeyguide

Discussion of everything related to the Theory of Evolution.

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Postby narrowstaircase » Sat Nov 04, 2006 7:24 am

soniaj wrote:What I would like to know is if there is a way for the body to recognise and pass on beneficial changes. And the idea of behavioral changes seems to be on another level as well. Taking for example the honeyguide, how does a given, complex, learned behavior become "instinctive"--as it seems to be with that bird?

Sonia


the best explanation i've come across is from an australian biologist 8) named Jeremy Griffith. whats surprising is that there aren't many sources that actually explain what an instinct is?!! you need to know what exactly instincts are in the first place - how they work with behaviour - and how they can be reinforced genetically. which is essentially what lamarkism is; reinforcing behaviours genetically. the emphasis is my own. i hope its what you were looking for :D

"As soon as nerve nets appeared in animals to co-ordinate the activities of their cells, the capacity to at least temporarily remember impulses through the nerve pathways was also aquired. As a consequence, memories would have been related and self-alterations or anticipations or predictions would have begun. Predictable regularities were identified (that is, the nerves had insights) and acted upon (the future was anticipated); at the same time genetic refinement learnt to block any insights which led to self destruction. As the brain (the nerve centre that developed for this information processing) developed, the genes 'watched over it' and brought it under control so that gradually the species learnt to anticipate or change its behaviour safely according to regularities which were identified in the nervous system. A gradual, hand-in-hand process of the genes 'following' the brain occured, the genes sheperding the brain away from self-elimination and reinforcing successful self-alterations.

At some very early stage in the development of nerves, soon after they appeared in primitive organisms, we can imagine mutations or varieties of these organisms occuring whose behaviour was affected by their nerve memories. Since the nerves were connected to what we now recognise as 'effector-muscles', the memories could affect muscles and thus bring about a movement. These self-induced (as apposed to genetically induced) variations in behaviour represented a new source of variety for adaptation for the species. Natural selection could reinforce modifications that were beneficial through, for example, selecting nerves that received certain memories over those which received other memories or, possibly, selecting some memory-to-muscle connections and not others. In time we can imagine it becoming possible for the nerve memories to be compared for similarities in experience and these insights being used to affect the organisms behaviour. Again, those memories which had beneficial results would be genetically reinforced and those which were self-eliminating would be genetically blocked or sheperded.

the sheperdings and reinforcements together constituted genetic orientation for the behavioural alterations induced by the organism's mind or mental self. They are what we term instincts.

Genetically refined or organised nerve pathways which invole little or no information association are termed reflexes; genetically reinforced and sheperded information associations are termed instincs.

...Tinbergen showed in his experiments with stickleback fish and gull chicks, 'complex' innate behaviour was controlled through the accumulation of 'simple' innate sign or cue triggers. For instance, Tinbergen found that gull chicks feed in response to the recognition of a red dot on their parents beak - they will even attempt to feed from a cardboard cutout as long as it carries a red dot... Instincts [are] simplistic.

The first instinctive containments or disciplines and reinforcements for the mind would have involved organising the animal to satisfy its basic needs for food, shelter, space and a mate. Biologists have referred to these primitive or base instinctive orientations or guidances as 'drives'.

So the genes followed the brain, sheperding it to safety. In recent years biologists have suspected that a theory first propounded in the early 19th century by a man called Lamarck had significance. Lamarck hypothesised that the habits aquired in a lifetime could be passed on to the next generation... Obviously what our mind decided did influence our chances of reproducing and therefore our genes' chances of reproducing, but only now can we actually see... the full significance of this 'genes following brain' association." (Griffith, J. 1988. Free: The End of the Human Condition. pg 123-126)
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Postby Mr Joe » Mon Nov 27, 2006 9:30 pm

i understand lamarckism (i think thats how its spelled :S) but what is the honeyguide?
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Postby biofanatic » Fri Dec 01, 2006 12:31 pm

DNA is not always located in the nucleus, i was taught that it is also located in the mitochondria in the cytoplasm which means we contain acquired genes from are Mothers and are passed on. As part of our genetic make up was due to an egg which contained DNA in the nucleus and also in the cytoplasm containing mitochondrial DNA which was also passed on with the egg which fused together with a sperm wich only contained DNA in the nucleus.Which means that i can pass on my "Characteristics" which i recieved from my mother from her cytoplasm and my offspring can pass on my Characteristics and so on....doesn't this refelct lamarcks theory to a certain extent?

open to any other rational explanations, suggestions, views and opinions, agreements, disagreements.
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