Evolution As Response Reaction Of The Genotype

[Aedes]

Originally Posted by Holiday20310401

Darwin's theory is supporting the idea that evolution occurs gradually right?

Except that modern evolutionary theory does not support gradual evolution. It happens in fits and starts, particularly due to selective sweeps from a sudden change in conditions or the sudden appearance of a highly advantageous genotype.

Mutation is random

Mutation is not random. It is more likely in telomeric regions than centromeric regions, it is more likely in A-T base pairs than in C-G base pairs, and there are epigenetic factors that can modify risk of mutation. Mutation mostly does not happen in a directed way because of environmental pressure, but it is not 100% random across the genome. There are predictable patterns to it.

...due to a vast expanse of genetic information, of past generations, and present entity, there would be a very quick instance in which that 'reason' would be fulfilled, thus making evolution happen in instances, not gradually. Therefore, are you purposely denouncing darwin's theory of evolution like I am.

Darwin's theory of evolution was groundbreaking for 150 years ago. But there have been enormous advances since then, so I don't see what the point is in dwelling on Darwin. Even if he had been wrong himself, it doesn't matter because modern evolutionary science is built on a whole lot more than his drawings of finch beaks.

Furthermore, as I mention above, evolution DOES happen to some degree in instances. But this has to do with the way selectively advantageous genotypes will rapidly become predominant over few generations, or the way selectively disadvantageous traits will be extinguished. This is one reason why intermediate forms are often absent from a fossil record, because they were too transient. Do some reading about "punctuated equilibrium".

[Holiday20310401]

So Darwin's theory is wrong?! Why am I learning it in school. I hate school, its biased.
Well I dont hate it, but wow there was a whole unit in biology course on the dang theory!
At least its wrong.

[Aedes]

Originally Posted by Holiday20310401

So Darwin's theory is wrong?!

No, it's NOT wrong -- It's foundational. Just as Einstein was not wrong even though his work has been supplemented over the last 100 years.

What you are learning as "Darwin's theory" is a lot more complicated than simply the work and writings of Darwin himself. His work has been greatly improved upon. No story about evolution would be possible without a mechanism, and at the time of Darwin there was no biological mechanism known for evolution. Evolution, as observed by Darwin, was inferred by looking very macroscopically at different overt phenotypes, like how finches had differently shaped beaks that were adapted to their food type. But evolution, fundamentally, is NOT morphologic or functional change. Fundamentally it is genetic change, and at the time of Darwin this was not established.

Gregor Mendel helped change that with his own foundational work in genetics; and molecular genetics has made the study of this subject so complicated that Mendel's work with peas seems very primitive. It wasn't until the 1940s and 1950s that we began to identify the molecules responsible for genetic information and their structure and function.

Furthermore, at the time of Darwin, the classification of organisms was basically derived from Linnaeus, i.e. morphological description along with the later stipulation that a species is determined by ability to procreate in nature. But species determinations are now made at the molecular level, and many organisms (especially microorganisms) have been reclassified even into different Kingdoms based on molecular work.

When I said that it doesn't matter if Darwin is wrong, that doesn't mean that he IS wrong. What that means is that he set in motion a movement that has been verified by a huge abundance of research over 150 years -- so his ACTUAL findings are incidental to our current understanding of the subject. After all, you can go to the Galapagos and make the same observations as he did. There's nothing private about his data or his work. He was just the first to string it together in the way he did.

[Doobah47]

Instead of relating the evolution of a genus to it's genotype, thus insinuating that intrinsic characteristics change to suit conditions, why not try the concept of a genus recognizing itself and changing somewhat 'consciously' - so an individual's evolution is like a self-observing phenotype making subconscious adjustments during growth.

Like a body entering a growth spurt, consciously recognizing a need to run fast, thus running fast in order to improve the strength of the legs - so a genotype is replaced by a self-observing phenotype.

[Aedes]

Originally Posted by Doobah47

why not try the concept of a genus recognizing itself and changing somewhat 'consciously' - so an individual's evolution is like a self-observing phenotype making subconscious adjustments during growth.

There are epigenetic phenomena that indeed change in response to conditions. The word epigenetic refers to NON-genetic processes that regulate gene expression.

However, this is NOT evolution because it does not change the genotype of germ-line cells. Thus, no adaptive genotype is passed on to subsequent generations. (This is excluding the circumstance by which certain behaviors will produce more procreative fitness -- so fat pale schlubs who play PS2 all day may be less likely to pass on their genes than people who work out, for instance).

Like a body entering a growth spurt, consciously recognizing a need to run fast, thus running fast in order to improve the strength of the legs - so a genotype is replaced by a self-observing phenotype.

But again, this individual behavioral adaptation is not pertinent to a discussion of evolution except insofar as the behavior may modify procreative fitness. Or except insofar as there is a genetic predisposition to engage that behavior.