When you claim something is beyond debate then disagreeing with you is precisely what you are defining to be the problem.
The expression of traits has nothing to do with selection. It has everything to do with whether the individual has the genes for those traits or not.
Speaking of sexual reproduction, genes can exist in a population but not be expressed because 1) the proper combination happens too rarely to be noticed or 2) in the natural environment the combination results in the death of the individual organism. Change the environment or select for the specific gene and it will be expressed. No mutation needs to have occurred.
A trait that is not encoded in the DNA will never be expressed, because it is not there. No amount of selection will cause it to be there.
Unless you can conclusively prove that it is not encoded in the DNA of any individual in a population you haven't proved that it is not there.
If a new trait appears, it is because the DNA was altered somehow to make it appear. The most common alteration is a point mutation, but other, more drastic alterations can and do happen.
Not if you are talking about a combination of genes to produce the trait.
DNA undergoes constant mutation. In evolution, that matters when the mutation(s) occur in germ cells--the sperms and eggs. According to the biochemistry professor who wrote this blog, a human zygote has ~130 mutations. Most mutations, of course, are DNA errors that missed being repaired.
Some things are just absurd and should be considered more carefully. If those mutations are truly random they would be predominately negative and quickly result in the non-viability of humanity.
The minority of zygotes who live long enough and reproduce will pass ~half of their mutations to their offspring--along with the ~130 new germ cell mutations they pass along.
Might out to check that ratio of positive mutations to negative mutations again. And assuming the the negative mutations are adding up to positive mutations because we are still alive is another one of those show your homework moments.
One cannot "agree" or "disagree"; the only possibility here is to accept or reject the evidence.
What evidence? I see clearly delineated species that occurred relatively suddenly followed by changes that are best characterized by species dying off. I see a mountain of assumptions that dwarfs the data and understanding we do have. I see you sparing no effort to defend your beliefs and expending none to test your theories. Anyone who fails to mindlessly parrot the official line is branded a charlatan and shunned.
Settled science is dead science. Even the most basic core of science is subject to reconsideration: Newton gives way to Einstein. Not so with evolution. You don't discard the old theory, you redefine the new observations to fit it. For you the earth will always be the center of the universe because it is "beyond debate."
When you claim something is beyond debate then disagreeing with you is precisely what you are defining to be the problem.
The basic mechanisms of genetics *are* settled. The basic mechanisms of DNA alteration *are* settled. The sciences of genetics and molecular biology, both of which are based in those mechanisms, moved beyond trying to establish that DNA mutates, or that DNA drives phenotype decades ago. You might as well try to debate whether photosynthesis in plants is a real phenomenon or not.
Speaking of sexual reproduction, genes can exist in a population but not be expressed because 1) the proper combination happens too rarely to be noticed or 2) in the natural environment the combination results in the death of the individual organism. Change the environment or select for the specific gene and it will be expressed. No mutation needs to have occurred.
A recessive gene that happens so rarely in a population that it is never seen is quite likely to disappear--it only has a 50% chance of being passed to offspring. In order for the effects of the gene to be seen, two individuals heterozygous for that gene have to mate and produce offspring, of whom 1/4 will express it. Selection is not a factor for a recessive gene that is never expressed. Selection cannot make an unexpressed gene suddenly express. Selection does not make two individuals carrying the same unexpressed gene find each other.
Selection would only be a factor if a rare gene is *not* recessive--in which case, it doesn't matter how rare the gene is in the population, it *will* have an effect on the individuals who have it. If the rare gene confers a survival advantage to those individuals carrying it, they are more likely to produce offspring than other individuals, and that gene may become more prevalent in the population. But--not always. Genetic drift--the accumulation of changes in gene frequency throughout a population is, for the most part, random.
Let's put it this way: the genetic traits for Down syndrome are not hidden until "selection" causes them to be expressed. Neither the mother nor the father of a Down syndrome child have Down genes. Down syndrome is caused when all or part of chromosome 21 is duplicated--a process that only occurs in the germ cell (the sperm or egg). Chromosome duplication is a common type of DNA mutation.
Let me reiterate: no amount of selection can cause a trait to appear if it is not encoded in the DNA. A new trait can only appear as a result of DNA alteration. Selective forces become relevant only after a new gene is expressed.
Unless you can conclusively prove that it is not encoded in the DNA of any individual in a population you haven't proved that it is not there.
I do not think it necessary to sequence the genome of every single human on the planet to conclude that we do not have genes to produce feathers. Nor do we have genes to produce an exoskeleton, pink hair, etc. I'm fairly certain that no amount of selective pressure is going to cause us to be able to digest wood, and that won't change--until an individual has a mutation in an enzyme gene that makes him/her able to digest wood, in which case selective pressure gives him/her a huge advantage for survival in a situation where food is scarce and wood is plentiful (otherwise, it's not an advantage, and there will be no selection).
Some things are just absurd and should be considered more carefully. If those mutations are truly random they would be predominately negative and quickly result in the non-viability of humanity.
Some things are just absurd and should be considered more carefully. If those mutations are truly random they would be predominately negative and quickly result in the non-viability of humanity.
You didn't read my last post carefully, did you? Mutations are absolutely random, and a large number of humans *do* die before their mothers even know they exist. Most mutations are not good or bad, but it does take only one bad one (out of the ~130 in the zygote) to be lethal. There is no need for a mutation to be beneficial to be passed on; as long as it is not lethal and the individual reproduces, any mutation has a chance of being maintained in the population.
I should also point out that DNA mutation isn't just a factor in reproduction. It can have a direct effect on your health. Cancers result from changes in gene expression...some of those changes are mutations, others are changes in DNA structure. And part of aging is that DNA changes in a very stereotypic and predictable fashion.
What evidence? I see clearly delineated species that occurred relatively suddenly followed by changes that are best characterized by species dying off. I see a mountain of assumptions that dwarfs the data and understanding we do have. I see you sparing no effort to defend your beliefs and expending none to test your theories. Anyone who fails to mindlessly parrot the official line is branded a charlatan and shunned.
Since when are species clearly delineated? What, exactly, are the "assumptions that dwarf the data"? I have yet to state a single opinion, assumption, or belief--everything I have said is backed up by mountains of scientific evidence. Does the fact that you don't want to actually read some of the (thousands of) scientific papers for yourself make those papers non-existent? Every Wikipedia article or webpage I have linked to has a ton of references. You can access and read those references for yourself. Those references have references, which you can also read. The references of references also have references--again, you have the right to read all of them. In the case of papers describing original research--you know, the process by which scientists painstakingly test hypotheses to establish the nature of reality--you are able to examine what the scientists did, what their hypothesis was, what their results were and how they interpret their results, and--if you really want--you can repeat their experiments for yourself and confirm their results. Or, if you don't want to repeat the experiments, you can find other papers written by scientists who repeated the experiments. We're way past trying to prove that DNA mutates (as if that were ever in doubt). We're way past trying to determine how it mutates. We're at the point where those processes are taken for granted, and we're trying to figure out the effect of X mutation on Y gene--a much more complicated proposition, because there are thousands of genes, and our level of knowledge about some genes is quite advanced, while we know nothing about others. And how do we determine the effect of mutation? We start out by purposely introducing mutations, and then we look at their effect. I did that all throughout graduate school.
Settled science is dead science. Even the most basic core of science is subject to reconsideration: Newton gives way to Einstein. Not so with evolution. You don't discard the old theory, you redefine the new observations to fit it. For you the earth will always be the center of the universe because it is "beyond debate."
That's exactly backwards. The current theory of evolution is quite different than that proposed by Darwin or any other scientist of his time or earlier. Remember, evolution is the process; the theory only describes the process. As we learn more about the process, we refine the theory. There is almost no legitimate scientist who doubts the fundamental process itself.