SPG wrote:Yeah, but is adapting the same as evolving? Like, I go out into the cold and I adapt. Did I evolve, or was the ability always there? When I grow up, did I evolve or follow a prescribed process? If I go to the gym and build big muscles, did I evolve or utilize existing features?
When people moved north of equator and put on clothes, thus hiding from the sun and turning pale, did they evolve or just remove a common nutrient? Are they really different then those south and still dark? If I pick up a tool to temporarily work on a job, did I evolve or simply adapt? If I go from the IT department to Accounting, did I evolve, or adapt?
In other words, is life basically the same today as it was a billions ago? The only difference is environment and experience?
Life today is definitely
not basically the same as it was a few billion years ago. Fortunately, human biology and physiology today are quite different from life back then, which pretty much consisted of prokaryotic cyanobacteria that made a living from photosynthesis.
These guys lived in an environment in which we humans, left to our own devices, would have lasted for less than 10 minutes. These single celled organisms didn't even have a nucleus. Their DNA was in the from of little circular plasmids that sort of roamed around the cell at will. The task of cyanobacteria in the evolution of the planet was to release oxygen into the atmosphere so we multi-celled organisms could eventually live here, as soon as evolution could come up with us.
A good working definition of evolution is the acquisition of new and heritable traits in a population. New and heritable traits means acquisition of mutations; that is, changes in the sequence of base pairs in the DNA. New DNA sequences lead to new proteins, which enable new physiology.
The experiment with mice described by the article referenced in the OP demonstrated that the genomes of the light-coat mouse population were statistically different, in terms of mutations in their DNA, from the genomes of the dark-coat population, and that both had evolved from the founding population through adaptation to their respective environments (light soil vs dark soil). Natural selection is demonstrated yet again.
Many of the adaptations SPG described in humans could be accomplished to some extent, without genetic changes. More likely over time, however, epigenetic changes would be involved.
Epigenetic changes, while heritable to some extent, do not arise from a mutation in the DNA sequence itself, but by means of chemical tags such as methyl groups attached to the outer surface of the DNA. This methylation does not alter the sequence of base pairs, but does help control how they are expressed in terms of relative rates of protein production.
Epigenetic changes that do not alter the DNA sequence can also include acetylation of the basesas well as methylation. It can also include methylation of the histone proteins around which the DNA is wrapped to form chromatin.
A well known example of a genetic mutation to the DNA itself, one that confers a heritable survival advantage, is the emergence of the nylonase enzyme in a strain of
Flavobacterium. This point mutation allows bacteria to derive energy from molecules that did not exist on the planet before the invention and manufacture of the nylon polymer in 1930s.
The nylonase enzyme is the result of a point mutation in the genetic sequence for a protein (enzyme in this case) that previously had no capability to use nylon by-products as food.
Judging from massive quantities of pseudo-scientific nonsense they come up with in response, the discovery of nylonase by the Japanese, as a crystal-clear example of evolution by mutation, appears to drive the creationist and ID communities crazy.