Defending Evolution from ID Distortions

Posts tagged “Natural Selection

YECs on Fossils and the “Evolutionary Timeline”

Because Young-Earth Creationists are so defensive of their model that requires the earth to be between 6,000 to 10,000 years old, they are always out to discredit the scientific date of the earth with anything they can fish out. They feel that if their interpretation of the Bible is wrong -to hell with other legitimate interpretations,- then their whole world will fall apart. This leads many YECs to make many bogus arguments for a young earth like  the decay of the magnetic field, the recession of the moon, etc, etc., etc., yada, yada, yada…. Then, another favorite tactic they use is to point out a fossil find and claim it is “out-of-place,” and that therefore the timeline is all wrong, and therefore their model of a 6,000 year old universe has to be right. I see this particular argument used more by Brian Thomas who is employed by the Insitute for Creation Research than anywhere else.

One of my favorite examples of  Thomas’s use of the “fossil out-of-place” argument is  from an article entitled “Fossil Footprints Trample Evolutions Timeline.” — It talks about arthropod trace-fossil foot prints which were found in Pre-Cambrian strata in Nevada. Thomas presented this find as if it were a blow to the Evolutionary theory because it would require some reevaluation of determining when arthropods appeared. It never occurred to them that this find actually hurts Creationism more than it could ever hurt the present theory of Evolution. More precisely, this discovery hurts the favorite Creationist argument about the so-called Cambrian”explosion” because it shows that complex, animal life was around 30 million years before.

There are several other examples that the Institute cites, and I’ll address some of them here just to show how they 1) show ignorance of the person making the claim, and 2) how are completely irrelevant to the topic of the “evolutionary timeline.” Further reading of ICR claims on the subject will show any informed person how the Institute takes certain scientific discoveries and takes them out of context to try to refute Evolutionary theory.

  1. One claim that the Thomas makes is that a  newly discovered amber trapped spider web too old for the timeline. A news article he cites of this fossil find, in fact, shows that spider webs had evolved long before it was first thought, however when one does more research on spider evolution, the apparent “harm” done to the timeline really doesn’t exist. This fossilized web’s age is estimated at 140 million years, while  the evolution of spiders is thought to have started some 400 million years ago. That gives the web about 260 million years to evolve, so there is no harm done here.
  2. Another claim that he made is that the T-Rex body structure evolved 60 million years “too early.” This claim is based on a newly discovered relative of the tyrannosaurs now called Raptorex. I seriously cannot help but see the irrelevance of this fossil to debunking the so-called “timeline.” It never crosses Thomas’ mind that rather than hurting the current theory of evolution, this helps it by aiding the construction of a phylogeny of the tyrannosaurs.
  3. Claims of human artifacts, such as evidence of boats and jewelry, are used to say that we have always been the same species. We now know that Homo neandertalensis had fassion sense, but nobody disputes this, so it is irrelevant. Also, multiple mtDNA tests show they are not the same species as Homo sapiens, despite the YEC model’s insistence. And the evidence that Homo erectus was a mariner is really not news since we knew that for over a decade (at least since 1998). Hence, this is also irrelevant.
  4. Another apparent contradiction of the timeline is the discovery of fossil ambers dating to the Carboniferous which lasted from 355 to 300 million years ago, though the first flowering plants known to the fossil record appear during the Cretaceous (125 million years ago). The Brian Thomas criticizes the scientist who discovered them of  evolutionary bias because he said this doesn’t necessarily mean that flowering plants appeared so early, but that it shows that aspects of them were starting to make an appearance. But at the same time, he doesn’t provide any credible evidence to the contrary, so they affectively fail to show how the timeline was falsified.

The only thing some of the examples above show is a slight reevaluation of  some of the current scientific understandings., but that’s all. On the other hand, some of the examples don’t affect out understandings at all. This kind of makes me wonder if the employees at ICR sees any unexpected scientific find as an inherent refutation of Evolutionary theory as we know it.

As I see it, ICR has a very odd definition of an “out-of-place” fossil. In one post entitled Cambrian Fossils Found in the Wrong Place,” it is argued that since soft-bodied creatures were thought to be stem ancestors to the Cambrian fauna were found in some of the same layers, one could not have evolved into the other because  the argument for evolution  “relies on the absence of these creatures in higher layers to support the assumption that they ‘diverged’ into ‘later’ life forms.” –This reminds me of the argument “If humans evolved from apes, why are there still apes.”  Even if  a certain animal evolved into another species, there is no reason to assume that evolutionary ecenario “relies” on the absence of the mother species.

So really, not a single one of the examples given of “out-of-place” fossils given by the Institute refute any of  the important aspects of Evolution, and any revision that is made from them, so far, is only minor. Any fossil that actually refutes our scientific understanding should be unexplainable, like fossil rabbits in the Cambrian, and so far, the Young-Earthers have failed.


Evolution, Mutation and Misconceptions

A common objection to the Evolutionary model is the idea that Mutations are a driving force for change. It is seen all over Creationist literature that mutations destroy information, and never add anything, or have any benefits. — For example, the Muslim Creationist Harun Yahya claims,

The direct effect of mutations is harmful. The changes effected by mutations can only be like those experienced by people in Hiroshima, Nagasaki, and Chernobyl: that is, death, disability, and sickness. […] Not surprisingly, no useful mutation has been so far observed. All mutations have proved to be harmful. (The Evolution Deceit, page 55)

A few months ago, while I was debating with a creationist, I found myself having to correct a major misunderstanding he had. He repeated an argument  about Natural Selection, saying that Natural Selection is not the same as Evolution because it produces nothing new. It just “selects'” — As soon as he said this, I remembered hearing the same thing from a Kent Hovind debate. 

As soon as he said that, I quickly corrected him. Nobody says that Natural Selection “creates” anything new. When I took History of Life in Biology, that was one of the things I was taught: “Natural Selection doesn’t create new traits.” Mutations create new traits, and natural selection then determines if the new trait is favorable or good enough for a living organism to survive in a certain enviroment.  — He then interrupted saying, “Mutations are always harmful!” When I corrected him on that, he then said, “Well, cancer is a mutation! . . So, you’re telling me that if we get a whole population with cancer — “ At that, I kept repeating myself that wasn’t what I was saying and told him to stop attacking a strawman.

 He then defied me to name one beneficial mutation, just one. At that, I gave the (probably over cited) anti-bacterial resistance. He then said that didn’t count because the bacteria didn’t pass on the newly acquired resistence to its descendants, and the new traits have to be heritable. — But Creationists who make that claim are demonstrably wrong. The fact is that newly resistant bacteria do pass on their newly acquired resistance to new generations. I also pointed out the evolution of the HIV virus -the “ultimate evolver”- which didn’t seem to  make even the slightest dent, as if I expected it to.

One often cited case of a beneficial mutation is the sickle-cell anemia. Kent Hovind, in a debate with Michael Shermer, mocked this example by comparing it to being beneficial in the sence of cutting off your feet so you do not get athlete’s foot. — But it’s not so simple. Kent Hovind apparently is ignorant of the qualifiers that determine whether or not the sickle-cell mutation is beneficial or not. If the mutation is in the heterozygous state, then the mutation is detrimental causing disease and early death. However, if the mutation is heterozygous, then that causes its carriers to be resistent to infection and malaria.

One really famous example of a beneficial mutation is the CCR5-Delta 32. This mutation occurs in chromosome three in the human genome. Individuals that carry this particular mutation are resistent to the HIV virus. The heterozygous variant of this mutation is able to slow down the progression of the HIV virus while the homozygous version of the mutation causes immunity to the virus. — It is obvious that the claim made by Harun Yahya in his writings is wrong. There are several examples of beneficial mutations. It has even gotten to the point that some Creationists now admit that they in fact exist, but they then try to put qualifiers on it.

Anyway, now that Creationists have accepted that mutations can be beneficial, they now changed tactics in order to salvage their ever evolving creation model. — One creationist from CMI, while talking about the CCR5-Delta 32, tries to work his way out by saying,

However, it clashes irreconcilably with the evolutionary view that the accumulation of mutations over time brings about upward evolution (increasing functional complexity).

 . . . And then later, he then cites a paper from Nature which mentions a downside to this particular mutation. The implication he seems to be trying to give is that because it can be associated with primary sclerosing cholangitis, then therefore it cannot be count as evidence. — Creationists make similar claims about antibiotic resistence of bacteria, saying that these mutations lead to a “loss of function.”

What these excuses show is a lack of understanding of how Evolution works with mutations. As I have already pointed out in a previous post, evolution doesn’t necessarily lead to increased complexity, though it may. But there is no pre-ordained goal. All that matters is if the change is heritable, and if it is, then that works as evolutionary change. — Also, no one has ever said that mutations that lead to evolutionary change cannot have a downside. There will always be a downside. What matters is if the variation is beneficial or good enough to survive in a certain environment. In an enviroment where there is plenty of AIDS, the CCR5-Delta 32 mutation would be beneficial. Natural Selection will favor those particular individuals that carry it.

Finally, there is Gene Duplication. I know that Creationists would love to pounce on this example and say “It’s just duplicated information.” — I wonder if these same Creationists would be interested in the fact that over 97% of human genes are duplicates. Anyway, gene duplication offers raw material for Evolution and mutation, though it is true that high rates of duplication often lead to high rates of gene loss also, (a fact that would be useless for Creationists to hijack for reasons mentioned above.) What happens is, a gene gets duplicated, and then the duplicate copy has no selection pressures, so it is now free to evolve and mutate on its own, though the gene doesn’t always survive.  

I’m sure that Creationists would love to object to new function ever being derived from duplicated genes, but the fact is that it does happen. A good example is the Eosinophil Cationic Protein (or the ECP) which is toxic to bacteria by making their cell mambranes porus. Also, it is useful in the management of Asthma, despite it’s limitations. — Then there is the Eosinophil-Derived Neurotoxin (the EDN) which helps to prevent viral infections, though it’s accumulation in the intestine is associated with tissue loss.

Furthermore, observations in the genomes of bacteria only aid the conclusion that gene duplication is a viable mechanism for Evolutionary change, as the divergence of duplicated enzymes seems to have been a main contributor -though not no only one-  to the causation of new species of bacterium.

One need not be a geneticist to research the claims of anti-evolutionists to come to the realization that almost everything they claim about mutations is spurious. Even though it is true that most mutations are harmful, it is also true that in certain environments some can be quite beneficial in which cases natural selection will favor them. Some gene duplicates also show neofunction completely debunking the idea that nothing new arises from mutation.

References:
Evolution and Disease, from ChemHeritage.org
Genetics Demystified, page 151. By Edward Willett
Beneficial Mutation, by Ningthoujam Sandhyarani. From Buzzle.com
Beneficial Mutations, from SkepticWiki.
Examples of Beneficial Mutations in Humans, from The Evolution Evidence Page.
Almost all human genes resulted from ancient duplication, by Roy J. Britten, from the Proceedings of the National Academy of Sciences.
Gene Duplication and Evolution of Gene Function, from Evolution and Developement Group.
Evolution by Gene Duplication, by Jianzhi Zhang, from TRENDS in Ecology and Evolution. Also see Positive Darwinian Selection after gene duplication in primate ribonuclease genes, by Jianzhi Zhang, Helene F. Rosenberg, and Masatoshi Nei, from the Proceedings of the National Academy of Sciences.
Eosinophil cationic protein: Is it useful in asthma? A systematic review, by Gerald C.-H. Koha, Lynette P.-C. Shekb, Daniel Y.-T. Gohb, Hugo Van Beverb, David S.-Q. Koha.
Eosinophil Derived Beurotoxin (EDN)
Evolution by leaps: gene duplication in bacteria, by Margrethe H Serres, Alastair RW Kerr, Thomas J McCormack, and Monica Riley. From Biology Direct.