Science Forums 2

[InfiniteNow]

Oh, HydrogenBond... How I've grown to laugh at your consistent misrepresentation of the process of evolution. Many of your conclusions might just be valid if only your premises were not so faulty.

Let's see...

Originally Posted by HydrogenBond

Here is an evolutionary observation that doesn't exactly fit the existing Darwinian logic. Humans, especially in western cultures, have been getting taller over the past centuries.

Actually, it fits fine. But wait... of course it might not fit YOUR definition of "Darwinian Logic." Let's see what we can determine.

Originally Posted by HydrogenBond

This was not due to a tall person having the most babies and gradually shifting the population in that direction. It is due to diet shifting genetics almost globally.

And what you leave out is how evolution would select for organisms that maximize the resources in their environment.

However, you act like you've found the achilles heal of evolutionary theory, when, in fact, the relationship (while complex) is quite well understood:

Human height - Wikipedia, the free encyclopedia

"Height is, like other phenotypic traits, determined by a combination of genetics and environmental factors. Genetic potential plus nutrition minus stressors is a basic formula. Genetically speaking, the heights of mother and son and of father and daughter correlate, suggesting that a short mother will more likely bear a shorter son, and tall fathers will have tall daughters.[66] Humans grow fastest (other than in the womb) as infants and toddlers (birth to roughly age 2) and then during the pubertal growth spurt. A slower steady growth velocity occurs throughout childhood between these periods; and some slow, steady, declining growth after the pubertal growth spurt levels off is common. These are also critical periods where stressors such as malnutrition (or even severe child neglect) have the greatest effect. Conversely, if conditions are optimal then growth potential is maximized; and also there is catch-up growth — which can be significant — for those experiencing poor conditions when those conditions improve.

Moreover, the health of a mother throughout her life, especially during her critical periods, and of course during pregnancy, has a role. A healthier child and adult develops a body that is better able to provide optimal prenatal conditions. The pregnant mother's health is important as gestation is itself a critical period for an embryo/fetus, though some problems affecting height during this period are resolved by catch-up growth assuming childhood conditions are good. Thus, there is an accumulative generation effect such that nutrition and health over generations influences the height of descendants to varying degrees.

The age of the mother also has some influence on the her child's height. Although 2 Esdras recorded that "Those born in the strength of youth" were taller than "those born during the time of old age, when the womb is failing"[67], studies in modern times have observed a gradual increase in height with maternal age.[68][69][70]

The precise relationship between genetics and environment is complex and uncertain. Human height is 90% heritable[71] and has been considered polygenic since the Mendelian-biometrician debate a hundred years ago.[72] The only gene so far attributed with normal height variation is HMGA2. This is only one of many, as each copy of the allele concerned confers an additional 0.4 cm, accounting for just 0.3% of population variance.[71]"

Originally Posted by HydrogenBond

All my siblings are taller than our parents and grandparents. This genetic change, in one generation, has little to do with Darwinian.

Actually, your genetics have not changed at all, your environment and available food sources have. If you wish to show otherwise, I welcome whatever evidence you have to support your suggestion that you and your siblings have experienced some sort of "genetic change, in one generation, that has little to do with Darwinian."

Seriously... You're mistakenly attributing to genetic change what is better described by nutrition. Cute idea, really, but it fails the test of reality pretty sharply.

Originally Posted by HydrogenBond

It has little to do with Darwinian mythology.

What is mythological about darwinian evolution? You've interested me in understanding why you need to cast aside the truth which is evolution with silly misrepresentations and deragotory labels, instead of actual evidence and empirically supported logic.

Originally Posted by HydrogenBond

Say this casual global height change had happened in an animal population from 10 million years ago. We find a fossil or two that shows animal x got taller within a thousand years. The Darwinian explanation would say: this taller animal x had a selective advantage. Maybe it could reach food better. This caused this particular mutation advantage to breed more, gradually shifting the entire population to get taller. It would be totally off the mark, but would be accepted as real. The discontinuous fossil data would appear to verify this theory. To suggest cause and affect, would label you as crazy.

You just aren't getting it. You misrepresent how the data would be described, and then attack the theory based on that misrepresentation. Do you really believe the only "darwinian" explanation would be that they could reach the fruit in higher trees? If so, it appears that you haven't picked up a biology textbook in over 40 years.

Of course environmental changes are considered, so I'm left to ask: What is your point, and why do you continue to misrepresent the way things actually happen?

If it's just ignorance, that can remediated. If it's some agenda or desire to crush an opponent to your faith, well then... that's quite another issue altogether.

I seriously encourage you to check the validity of your premises before making further speculations. It will help you tremendously.