Yahzi
12th May 2006, 02:22 PM
Here is a very simplified version for people (like me) who know nothing about biology. In real life, everything is more complex, longer, with more complicated interrelationships.
So first, let’s start with a (simplified) strand of DNA. All DNA is a long chain of the same 4 complex molecules (called neucleotides) in various orders.
CCAACTTGCAT
After much study, scientists decided to break these chains up into blocks called genes, and named them.
[CCAA][CTTG][CAT]
G1......G2.......G3
Various combinations of genes produce various results. For example, if you have G1, G2, and G3, you have green eyes. Having G2 and G3 but not G1 means blue eyes. Having none of them means black eyes. (In real life, G1 might also affect other things as well, like left-handedness or blood type.)
Now we all understand a mutation means something goes wrong, and that gene is either broken or changed. Suppose a person had all three genes in the above example, but G87 had been mutated and broken. That person would have black eyes just like a person who didn’t have the gene at all.
But where do mutations come from? The answer is the copying process. When you go to make a new person, you have to copy your DNA. There is a chemical process that starts at the top of the DNA chain, and copies each molecule, one at a time, like adding popcorn onto a string. But what if something goes wrong?
CCACTTGCAT
Woops! I got interrupted and accidentally dropped the second A on the floor. Now it’s gone, and the new DNA strand is the blueprint for a person with blue eyes. Sorry.
[CCA][CTTG][CAT]
G???...G2.......G3
And here we come to the point: The copying process that introduces mutations does not know what gene it is copying. It only copies molecules (the letters) one at a time, not genes as a single object.
So if you posit that micro evolution is possible – that the genes that control for eye color can be mutated (and we know mutations occur!) – then how do you explain how this copying process always works perfectly when it is copying the genes for sexual reproduction? And if it doesn’t, then mutations can be introduced into the sexual reproduction equipment. Assuming those aren’t fatal, and do not immediately lead to non-fertility, this new creature could reproduce and pass along the gene. Then suppose you get another small change in the sexual function: now the new creature can still interbreed with its mutated fellows, but suddenly cannot interbreed with the original stock. Now suppose the new creatures and the old creatures are just plain healthier than the middle creatures, and so eventually all the middle ones die out (their niche is taken over by the new ones). And what do you have? Two species that cannot interbreed. Two kinds from one. (This argument works for any mutation, including new organs, unless you contend that it is impossible for mutations to eventually add up to something good. Since this contention violates the laws of information science – for example, I have personally extracted more information from a weak signal by introducing randomness to it – we can dispense with this contention.)
The essential point here is that the copying process does not know what it is copying. It copies molecules, not genes. Ergo, if a mistake is possible anywhere, then it is possible everywhere. And since mistakes need not always be fatal or infertile, you can eventually make enough mistakes that you aren’t where you started from.
To posit that species cannot evolve even while genes can change is to posit that some mechanism prevents errors in the speciation gene-copying but not in the other gene-copying. But gene-copying (that is, reproducing a strand of molecules one molecule at a time) is well understood, and there is no mechanism, nor is there room for or the possibility of such a mechanism.
Given this, the distinction between macro and micro evolution is untenable, insomuch as it requires a mechanism (protecting some genes but not others during copying) that does not exist.
Does this help?
So first, let’s start with a (simplified) strand of DNA. All DNA is a long chain of the same 4 complex molecules (called neucleotides) in various orders.
CCAACTTGCAT
After much study, scientists decided to break these chains up into blocks called genes, and named them.
[CCAA][CTTG][CAT]
G1......G2.......G3
Various combinations of genes produce various results. For example, if you have G1, G2, and G3, you have green eyes. Having G2 and G3 but not G1 means blue eyes. Having none of them means black eyes. (In real life, G1 might also affect other things as well, like left-handedness or blood type.)
Now we all understand a mutation means something goes wrong, and that gene is either broken or changed. Suppose a person had all three genes in the above example, but G87 had been mutated and broken. That person would have black eyes just like a person who didn’t have the gene at all.
But where do mutations come from? The answer is the copying process. When you go to make a new person, you have to copy your DNA. There is a chemical process that starts at the top of the DNA chain, and copies each molecule, one at a time, like adding popcorn onto a string. But what if something goes wrong?
CCACTTGCAT
Woops! I got interrupted and accidentally dropped the second A on the floor. Now it’s gone, and the new DNA strand is the blueprint for a person with blue eyes. Sorry.
[CCA][CTTG][CAT]
G???...G2.......G3
And here we come to the point: The copying process that introduces mutations does not know what gene it is copying. It only copies molecules (the letters) one at a time, not genes as a single object.
So if you posit that micro evolution is possible – that the genes that control for eye color can be mutated (and we know mutations occur!) – then how do you explain how this copying process always works perfectly when it is copying the genes for sexual reproduction? And if it doesn’t, then mutations can be introduced into the sexual reproduction equipment. Assuming those aren’t fatal, and do not immediately lead to non-fertility, this new creature could reproduce and pass along the gene. Then suppose you get another small change in the sexual function: now the new creature can still interbreed with its mutated fellows, but suddenly cannot interbreed with the original stock. Now suppose the new creatures and the old creatures are just plain healthier than the middle creatures, and so eventually all the middle ones die out (their niche is taken over by the new ones). And what do you have? Two species that cannot interbreed. Two kinds from one. (This argument works for any mutation, including new organs, unless you contend that it is impossible for mutations to eventually add up to something good. Since this contention violates the laws of information science – for example, I have personally extracted more information from a weak signal by introducing randomness to it – we can dispense with this contention.)
The essential point here is that the copying process does not know what it is copying. It copies molecules, not genes. Ergo, if a mistake is possible anywhere, then it is possible everywhere. And since mistakes need not always be fatal or infertile, you can eventually make enough mistakes that you aren’t where you started from.
To posit that species cannot evolve even while genes can change is to posit that some mechanism prevents errors in the speciation gene-copying but not in the other gene-copying. But gene-copying (that is, reproducing a strand of molecules one molecule at a time) is well understood, and there is no mechanism, nor is there room for or the possibility of such a mechanism.
Given this, the distinction between macro and micro evolution is untenable, insomuch as it requires a mechanism (protecting some genes but not others during copying) that does not exist.
Does this help?