Posted: Aug 11, 2010 7:01 am
Templeton wrote:
It is important to look at how our brain and genes communicate in order to understand this process.
Also it is important not to assume that because Lamarck was refuted about 150 years ago that he was entirely incorrect. Lamarck believed that physiological changes would occur in a species simply by a change in behavioral pattern, and that change would begin to happen within the next generation. Lamarck's example was of the short necked giraffe and the long necked giraffe. Obviously at the time there was insufficient scientific knowledge to substantiate his claims. Also the problem was that the change that was expected to be seen was of a measurable physiological change. That did not happen.
What wasn't considered nor understood at the time was that before any physiological change could occur there needed to be a behavioral change to begin the process. (This is the slow process; something quicker would be an epigenetic change) A change in behavior necessitated by an environmental impact would begin a change in physiology.
In a previous discussion on this topic I used an example of a fish, one which most of us are familiar; where the fish swims into shallower water among the weeds, and rocks because food is more readily available. In order to navigate these shallower waters the fish would have to use its tail and fins as leverage to maneuver. If the fish was successful in this method of procuring food it would create a memory of the process, and would repeat the process. In repeating (How many times?) the process the fish would create a behavioral change that altered its genetic expression. When the fish reproduces what genetic traits would be passed on - the genes that are expressing at the time of conception.
Successive generations of this type of behavior would result in the fish developing stronger bones and muscles in its fins that would become appendages, and when the fish moved into even shallower and came out of the water it would develop lungs, and in thousands or millions of years we believe we know the rest of the story.
Wait a minute, hold up. It is possible that you are aware of some fundamental scientific research that I don't know of, but I'm pretty sure you've got things backwards here - at least as it applies to most cases of behavioral evolution (and probably all, unless I have missed some important scientific work). If we are arguing that the fish has a genetic imperative to swim in a particular direction, then I can agree that environmental factors can influence the decisions made by the fish which will alter it's current behavior - this much is undeniably true (I don't think your use of the term "genetic expression" would accurately apply though). However, this does not create any inheritable material to pass on to its offspring. It does not work that way.
What happens is that you have a species of fish which has a tendency to swim in a particular direction. Through variation, evolution has equipped each individual with a slightly different tendency - so some might swim straight down stream, some might veer to the left a bit, some to the right, some might even simply sit still in the river (and I imagine those would die off quite quickly). But then you'd have the fish that have a tendency to swim against the current, and in doing so in this hypothetical situation, they end up having a greater access to food. Now, in this situation, the inheritable behavior is this genetic predisposition toward swimming upstream. In other words, If there was no genetic tendency to swim in that direction already present, and it was something that was produced entirely by environmental factors that lead to these fish swimming upstream - then it would not, and cannot, be passed on to their offspring (except through cultural transmission).
If you're referring to cultural transmission which leads to an evolutionary development of physical body parts, then there is no argument from me there - but your argument above is wrong. An interesting example of this that we can see happening before in real time is the New Caledonian crow behavior. They have evolved genetic tendencies which help them build tools for "fishing" grubs from trees which is passed on through standard evolutionary means, and not Lamarckian processes. Interestingly, they then learn their own "culture's" method of creating tools through cultural transmission so each population on the island have their own unique tools.
Templeton wrote:Many of us are familiar with how they brain and genes speak to each other. In the example of the fish it is at a simpler genealogical species that existed in a basic survival mode, with humans, because of the incredible amount of chemical messengers we produce (Emotions) as a species the process can be complicated to say the least.
Hmm.. you're being entirely unfair to fish (and animals in general) here. No animal relies purely on "instinct" or genetic behaviors to survive, unless perhaps if you go all the way back to single celled organisms (and even here I would argue against that). All animals are equipped with the tools to change their behaviors according to what the environment dictates, within reason. Humans, arguably, are better at it than most animals but this is a difference in degree, not kind. We have the same basic learning tools that all living things do, we have just had the fortune of a few lucky events in evolutionary history to push us forward.
Templeton wrote:What makes us different as a species is that we have the ability (Those most don’t always use it) to be consciously aware of our behavioral choices. We can make choices that run contrary to basic survival instincts (behavioral patterns), as referenced earlier with altruism and abstinence.
Just the example of inkaStepa being aware of this behavior in other women means that she can exact control over her own genetic propensity to possibly behave in the same manner by becoming aware of the behavior. Her actions are also a behavior and in this process of understanding these behaviors she may also change genetic expression. What is truly awesome is that through consciousness we have the potential to become deterministic to our genetic evolution. Ha, lol, please excuse me if I add a caveat to that last statement; Theoretically speaking of course.
Sure, but unfortunately our behaviors are determined by environmental laws as well as genetic ones
