Ok, you are asking some serious questions. I shall have to check up on the frequency of mutations. From what i gathered, 'not that rare' is the correct term to use because they are not as frequent as other physiological effects, but it be false to claim they are so rare that after tens of thousands of years in tens of thousands of individuals, a useful mutation could not occur.
As for harmful mutations, anything that doesn't aid the survival of the individual and the species is wastage. It does not continue and becomes bred out, in effect.
As to a company not investing in this process, that suggests that it isn't carried out by anyone who can add up. Evolution does not case about efficiency studies. If it takes ten thosand years and ten thousand individuals to make a 1% step (that is all that Dawkins calculated would be needed to evolve the eye in ..what.. 29 generations, wasn't it? Don't be tempted to pass on your preferences to nature. It does what it does, efficient or not.
I will try to find out exactly how mutations work though I might hope that Rifleman might bring his expertise to bear, but this does seem to be just asking a few clarifying questions about a process that should have been shown now to be feasible, workable and in total accord with the evidence.
some popcorn and an ice- cream later...
This is an overview of how mutations work, how frequent they are and how they adapt organisms beneficially.The information comes from many sources, so I would prefer not to give links - the same sort of information can be found on several sites.
A mutation is a permanent change in the DNA sequence of a gene. Mutations in a gene's DNA sequence can alter the amino acid sequence of the protein encoded by the gene.
How does this happen? Like words in a sentence, the DNA sequence of each gene determines the amino acid sequence for the protein it encodes. The DNA sequence is interpreted in groups of three nucleotide bases, called codons. Each codon specifies a single amino acid in a protein.
A mutation is a permanent change in the DNA sequence of a gene. Sometimes mutations in DNA can cause changes in the way a cell behaves. This is because genes contain the instructions necessary for a cell to work. If some of the instructions to the cell are wrong, then the cell may not know what it is supposed to do!
There are two ways in which DNA can become mutated:
Mutations can be inherited. This means that if a parent has a mutation in his or her DNA, then the mutation is passed on to his or her children.
Mutations can be acquired. This happens when environmental agents damage DNA, or when mistakes occur when a cell copies its DNA prior to cell division.
Most of the mutations that we think matter to evolution are "naturally-occurring." For example, when a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation.
Mutations are changes in the genetic code, which leads to change in the population. Individual mutations are meaningless, but population mutations usually have more profound effects. As said above, most mutations are negative; however, those mutations that have no harmful effect either lead to evolutive changes on the population or remain dormant on the genome.
For example, the sickle cell gene is an example of a mutation that can be both positive and/or negative. People in Africa that have one copy of the sickle cell mutation, do not die of Malaria, yet if they have two copies they die of sicke cell anemia.
Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not "try" to supply what the organism "needs." Factors in the environment may influence the rate of mutation but are not generally thought to influence the direction of mutation. For example, exposure to harmful chemicals may increase the mutation rate, but will not cause more mutations that make the organism resistant to those chemicals. In this respect, mutations are random — whether a particular mutation happens or not is unrelated to how useful that mutation would be.
For example, in the U.S. where people have access to shampoos with chemicals that kill lice, we have a lot of lice that are resistant to those chemicals. They have evolved a resistance. This is why we have a constant drugs race with resistant strains of disease. Nobody says it's nice, but it is a fact.
People use warfarin to kill rats
Most of the rats die, but some don't because of a mutation - a change in the genetic code
A mutation in the rat's sex cells makes its offspring resistant to Warfarin.
The offspring survive and have their own offspring
Mutated gene is passed on and is common in the rat population
This is natural selection in action.
How does the mutation happen, how can it actually become resistant to the warfarin? How do the chromosones know how to become resistant?
Most likely the mutation occurs during DNA replication. As the DNA replicates the DNA polymerase goes along the strand of DNA and adds in the corresponding bases to opposite strand (A to T C to G) It is possible that the DNA polymerase makes a mistake and attache the wrong base. This can cause a new mutation. It is possible that this mutation could make a rat resistant to a particular poison. This rat will survive, and pass the mutation onto its offspring. who will also be resistant. eventually only those with the mutation will survive and the entire population will become resistant.
How often do they occur? Well, apparently they mutations occur all the time, with every DNA replication, The question is, how likely is it that a mutation will turn up just handily to take advantage of an ecological niche?
Replication occurs simultaneously at multiple places along a DNA strand.
Because human DNA is so very long (with up to 80 million base pairs in a chromosome) it unzips at multiple places along its length so that the replication process is going on simultaneously at hundreds of places along the length of the chain. Eventually these areas run together to form a complete chain. In humans, DNA is copied at about 50 base pairs per second. The process would take a month (rather than the hour it actually does) without these multiple places on the chromosome where replication can begin.
There are estimated 50 million or 50 trillion bits of DNA in the human body. It would seem to me that this is not so much a chance mutation coinciding with just the opportunity it needs (which I agree would look statistically improbable) but more like a board with a microscopic hole in being bomdarded every day of a hunded centuries by radiated particles. It would be statistically improbable that one would not go through the gap and probably impossible that, out of a thousand readiating sources, not one particle would hit in the right place.
Since all cells in our body contain DNA, there are lots of places for mutations to occur; however, some mutations cannot be passed on to offspring and do not matter for evolution. e.g The effects of mutations on an apple with a somatic mutation
Somatic mutations occur in non-reproductive cells and won't be passed onto offspring. For example, the golden color on half of this Red Delicious apple was caused by a somatic mutation. Its seeds will not carry the mutation.
The only mutations that matter to large-scale evolution are those that can be passed on to offspring. These occur in reproductive cells like eggs and sperm and are called germ line mutations.
Effects of germ line mutations
A single germ line mutation can have a range of effects: A single mutation caused this cat's ears to curl backwards slightly, or snake to have a more advantageous camouflage.
No change occurs in phenotype.
Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.
Small change occurs in phenotype.
A single mutation caused this cat's ears to curl backwards slightly.
Big change occurs in phenotype.
Some really important phenotypic changes, like DDT resistance in insects are sometimes caused by single mutations. A single mutation can also have strong negative effects for the organism. Mutations that cause the death of an organism are called lethals — and it doesn't get more negative than that. (Since this is a big quote, I give the source)
http://evolution.berkeley.edu/evolib...0/mutations_05
There are some objections "Mutations are actually an enemy of evolution."
http://www.creationdefense.org/06.htm
Another problem is mathematical; mutations are very rare. They occur only once in every ten million replications. The chance of two related mutations occurring is one in 100 trillion; given the abundance of genes in living organisms, however, mutations can and do occur. Even so, most mutations are harmful, leading to death of the organism before birth or a loss of a specific function. Only one in 1000 are not harmful and most of those are neutral, having no effect on the organism. Certainly this is why mutations are to be avoided. Mutagenic radiation and chemicals are avoided, not embraced.
This
appears to be correct but is overlooking the sheer quantity of mutations going on all the time. Big changes as in radiation are best avoided - but they are not the natural mutation method and that particular point is irrelevant.
Yet, another problem for mutations is that much of what is called mutation is actually genetic variance. It was once believed that flies resistant to DDT were mutants. Considering the impossibility of mutations mathematically, they looked for another explanation
I have seen nothing about this mathematical impossibility other than amongst those who wish to discredit evolution theory. It does not seem that the mathematical objection really stands up.
mutations are never seen to produce a new species in the laboratory.
This is asking too much. The steps taken to produce a significant change in an organism are surprisingly quick. 100,000 years in primates, a lot faster in fruit -flies, but even then, this 'micro evolution' change (which is accepted by some creationists, apparently) is within a single species. For the changes to become so large (as in the Cetan sequence of fossils ) as to be undeniably a different species, we would have wait a long time (Ambulocetus natans, which lived about 49 million years ago took around a aurprisingy short ten million years or so to the Basilosaurids of the late Eocene around 41 to 35 million years ago. That's still a long time for the creationists to wait to see what they would accept as a species change.) so it's unreasonable to expect it to occur within our history, let alone our lifetime (though having cats turn into dogs in the laboratory would prove nothing to me, let alone to a creationist.
Evolution requires a net increase in the quantity and quality of genetic information....The problem is that mutations ordinarily cause a loss of information, sometimes a transfer of information, but never an increase of information. Thus, mutations go the wrong way, because evolution requires limitless genetic expansion. Instead of an explanation for origin of life, mutations are actually an explanation of the origin of death and disease.
As explained above, this 'wrong way' idea is quite false. the development of resistance to disease, poisons or improvement in hearing apparatus is beneficial to the organism and is adding information. But isn't it true that it can't be added?
"Creationists get by with this claim only by leaving the term "information" undefined, impossibly vague, or constantly shifting. By any reasonable definition, increases in information have been observed to evolve. We have observed the evolution of
increased genetic variety in a population (Lenski 1995; Lenski et al. 1991)
increased genetic material (Alves et al. 2001; Brown et al. 1998; Hughes and Friedman 2003; Lynch and Conery 2000; Ohta 2003)
novel genetic material (Knox et al. 1996; Park et al. 1996)
novel genetically-regulated abilities (Prijambada et al. 1995)"
http://www.talkorigins.org/indexcc/CB/CB102.html
It is misleading - one might say deceitful if one did suppose that they really knew no better- to make this 'information cannot be added' claim.
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Some Simple Observations
There is hard evidence for bipedalism being developed in primates. Speculation about how mutations contributed to that is does not alter that hard evidence that somehow it did.
