6th April 2009, 11:19 AM
lazy that's not entirely correct. The cells don't "pick up" any changes. Genes are completely blind to not only their environment, but the body they are in. They just do what they do.
Essentially certain genes will change over time, this always happens. Sometimes dark bears show up in polar environments due to mutations. The difference is that in a polar environment, these bears tend to die, so it never goes any further down that chain. However, in another environment, it may be successful.
Part of it is a misunderstanding of what a gene is. A gene is not a descrete "bit" of DNA. You can't point to a part of a chain of DNA and say "this is a dividing line between this and the next gene". A gene is basically just a section OF DNA, of it's base components, and some are longer or shorter than others. The thing that defines what a gene is is basicaly it's ability to survive through the generations. For example, they all can't pass a certain length limit because past that limit, the odds of them being severed during reproduction are too high and they can't survive. Some genes have the survival "strategy" of simply being really small and being attached to other genes. They don't have any real effect on the body. The important thing is the genes don't care about the body, they just care about themselves, and I use "care" in an anthropomorphised sense, not in a literal one. They're just bits of molecules.
Also, a "mutation" is far more wide spreading than one tends to think. Since all a gene is is a combination of aleles or base pairs, ANY change counts as a mutation. Sexual reproduction is a massive number of mutations in this sense. After all, you can't really say that there are NO new genes when you have literally shuffled together two people's entire genomes and made a brand new unique one. To say that's not "really" any new genes is like saying that randomly shuffling the 1's and 0's of a program isn't REALLY producing new information because you never added a 2. You only have 4 base pairs to work with. What makes a new gene is just the order they are combined. Further, a gene's effect is not an absolute. A gene isolated from the rest of the genome codes for nothing. It needs context. A gene's environment in terms of it's surrounding genes is what's important.
And you don't need to take my word for it, take a look, it's in a book, such as Richard Dawkin's "The Selfish Gene". I've been reading all manner of web sites from various biologists and they all agree with the same thing. There is NO awareness at the gene level of what's going on. It's all blind. Another book to illustrate the point would be "the blind watchmaker".
But, it is NOT totally random. The mutations are pretty much random occurances, this is true. However, selection is anything but random. The natural selection part is what does the work.
Essentially certain genes will change over time, this always happens. Sometimes dark bears show up in polar environments due to mutations. The difference is that in a polar environment, these bears tend to die, so it never goes any further down that chain. However, in another environment, it may be successful.
Part of it is a misunderstanding of what a gene is. A gene is not a descrete "bit" of DNA. You can't point to a part of a chain of DNA and say "this is a dividing line between this and the next gene". A gene is basically just a section OF DNA, of it's base components, and some are longer or shorter than others. The thing that defines what a gene is is basicaly it's ability to survive through the generations. For example, they all can't pass a certain length limit because past that limit, the odds of them being severed during reproduction are too high and they can't survive. Some genes have the survival "strategy" of simply being really small and being attached to other genes. They don't have any real effect on the body. The important thing is the genes don't care about the body, they just care about themselves, and I use "care" in an anthropomorphised sense, not in a literal one. They're just bits of molecules.
Also, a "mutation" is far more wide spreading than one tends to think. Since all a gene is is a combination of aleles or base pairs, ANY change counts as a mutation. Sexual reproduction is a massive number of mutations in this sense. After all, you can't really say that there are NO new genes when you have literally shuffled together two people's entire genomes and made a brand new unique one. To say that's not "really" any new genes is like saying that randomly shuffling the 1's and 0's of a program isn't REALLY producing new information because you never added a 2. You only have 4 base pairs to work with. What makes a new gene is just the order they are combined. Further, a gene's effect is not an absolute. A gene isolated from the rest of the genome codes for nothing. It needs context. A gene's environment in terms of it's surrounding genes is what's important.
And you don't need to take my word for it, take a look, it's in a book, such as Richard Dawkin's "The Selfish Gene". I've been reading all manner of web sites from various biologists and they all agree with the same thing. There is NO awareness at the gene level of what's going on. It's all blind. Another book to illustrate the point would be "the blind watchmaker".
But, it is NOT totally random. The mutations are pretty much random occurances, this is true. However, selection is anything but random. The natural selection part is what does the work.
"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question." ~ Charles Babbage (1791-1871)