Evolution Part 4– Natural Selection

Natural selection is the engine of evolution. Regardless if one is talking about micro or macro evolution, natural selection is what makes it go. It is often referred to as survival of the fittest. We can see selection going on around us. A prime example is how the population of an organism changes during selection. Each species has enormous potential whether it is disease resistance of on individual over another or resistance to antibiotics in a particular bacterium. This diversity allows species to survive.

Each individual in a species is just a bit different. Maybe one has a longer neck or is a bit faster. One might have a slightly different coloration. It is this difference that natural selection works with and if one of the differences gives that individual some benefit over the others then they have a better chance of reproducing and passing this trait on. How do these differences come about? Most are due to mutations in the genome but in some cases, single celled organism, genes can be passed from one individual to another. Once we get passed the unicellular it is mutation that brings about the difference. Mutation however is slow, undirected and most often harmful. The fact is that over 70% of all mutations are harmful if not fatal to the organism. In order to change from one species to another, enormous amount of time is involved.

Natural selection has some problems. First, some trait has to first exist in order to be selected. Natural selection cannot look to the future or plan. It cannot select something in order for another mutation to take advantage of. It is random. Next, just because a trait provides a benefit does not mean it will be passed on to future generations. The individual may die before it can reproduce. The trait may lie on a recessive gene and not be passed on to others.

Every example I have ever seen for natural selection is based on microevolution, that is change within a species. In most instances, the population still has individuals with and without the desired trait. I will give two examples, the first has been in every basic biology textbook since the 1960’s. That is the peppered moth. For those who are unfamiliar with this example, the peppered moth had two varieties, one that was basically white with black spots and the other black with black spots. In England where coal fired plants produced electricity, ran machines and heated homes the trees where the moths lived and fed became covered with soot. This gave an advantage to the darker moths and they soon became the dominate variety. But, after the coal plants were cleaned up and the trees became less sooty, what happened? The lighter colored moths became dominate again. So the peppered moth stayed the same and the only change was the ratio between lighter and darker colored moths.

The next example is antibiotic resistant bacteria. In every strain these seems to be some bacteria that are naturally resistant to any antibiotic. Those resistant bacteria survive and reproduce while the others are killed. Still some bacteria that are not resistant survive. But even if they did not survive, the resistant bacteria are still the same species that existed at the start. If you start with a strep culture and keep introducing antibiotics you will end up with strep bacteria that are resistant but you will not end up with a bacteria that is not strep.

Species on the earth seem to have a remarkable amount of diversity within the species. The domestic dog is probably the best example I can think of. From the giant mastiffs and Saint Bernard’s to the tiny toy poodles and terriers all are dogs. They may look completely different but if allowed to interbreed that will revert back to original form.

As to macroevolution, it seems there are no examples to be found today. Species are remarkable stable. Dogs product dogs. Cats produce cats. Reptiles product reptiles and mammals produce mammals. Each according to its kind. We just do not see any new types of animals evolving and as to total new class of animal. But we are told to believe that this was going on in the past. That fish gave rise to amphibians that in turn gave rise to reptiles. The reptiles gave rise to both birds and mammals and the while we still have fish, amphibians, reptiles, birds and mammals.

I posed this example to a comment on my first post on evolution and got this reply. “Once a family of animals has begun to specialize its evolution only becomes more specific. The point is that our early ancestors were non-specialized, so birthed many family of animals. They also directed me to Google articles on phylogenetic trees to aid their argument. You can find one such article here, http://en.wikipedia.org/wiki/Phylogenetic_tree. However there seems to be a number of phylogenetic trees and not a great consensus on which one if any is correct. There are also limitations to such trees as you can see from this quote from the article “Although phylogenetic trees produced on the basis of sequenced genes or genomic data in different species can provide evolutionary insight, they have important limitations. They do not necessarily accurately represent the species evolutionary history. The data on which they are based is noisy; the analysis can be confounded by horizontal gene transfer, hybridisation between species that were not nearest neighbors on the tree before hybridisation takes place, convergent evolution, and conserved sequences.” Please refer to the entire article.

What I find troubling about this argument as to why macroevolution has “stopped” is twofold. First, dinosaurs were highly specialized and yet they were able to evolve into both birds and mammals. Their high specialization is showed by the wide variety of dinosaur species. The second problem is that this specialization argument is circular. Essentially it boils down to, why don’t mammals evolve into something different? Because they are too specialized. How do we know they are too specialized? Because they only produce more mammals.

It also ignores one of evolutions sacred cows, junk DNA. We are told that much of the DNA in species is so called junk DNA, that is it has not useful purpose and is a hold over form some distant ancestor. Yet if we still have all this useless DNA, then why can’t that junk mutate and give rise to another type of organism? Did mutations suddenly stop? If not then no matter how specialized an organism is it would seem to me that if the right mutation comes along it should still be selected and a new organism evolve and why not a new class. Or are the number of classes somehow preordained. If so by whom? Of course this also ignores new findings in the human genome that the so called junk DNA does indeed have a purpose and there may not be any junk. Junk DNA falls into the trap of thinking that because we do not know what a function something has it must not have a function. Of course it now appears that the so called junk DNA does indeed have functions. The Encode project, or Encyclopedia of DNA Elements, has found that almost 80% of the genome is biochemically active and they expect that eventually they will find that all or almost all of human DNA serves a useful purpose. You can read the Wall Street Journal article about the Encode project here http://online.wsj.com/article/SB10000872396390443589304577633560336453228.html or go to the Encode site here http://www.genome.gov/10005107 or for those who do all their research on Wikipedia here http://en.wikipedia.org/wiki/ENCODE .

I have to admit that this argument as to why we do not see new organisms or classes still arising also gave me a smile. This is just the exact argument that creationists have been making for centuries, kind only begets kind.

Natural selection works on the micro level; we have examples all around us. What we do not have are examples of natural selection working on the macro level to evolve new types. On the macro level the only thing I see working is the extinction of species as their environment changes or they are unable to adapt to humans. No clear examples exist of one type of organism evolving into another type. We are just asked to believe and have faith that some unidentified time in the future that all the missing information will be found.

Next time, think there are no problems with evolutionary theory? Guess again, Charles Darwin himself listed problems with his theory in his book The Origins of Species. These problems still exist but you will not find them mentioned in biology texts.

Have a blessed day,

David

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About dwwork

The name of this blog is taken from 1 Peter 3:13 - “always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect, keeping a clear conscience. This verse became special to me over ten years ago when I was asked to teach an adult Sunday school class on Christian apologetics. This interest grew over the years to the point that I took some graduate level classes in apologetics. I think the best way to be prepared to give and answer to everyone who asks is to know scripture. It is my hope that through these short devotionals the reader will become more familiar with each verse. I have tried when possible to make them personal hoping in some small way to show that God’s word written over two thousand years ago is still relevant today. In the writing of these short devotionals I have been able to better understand how God’s word impacts my life. It is my hope that you too will come closer to our Lord Jesus and develop a closer relationship with Him. Finally, if the reader finds anything in conflict with scripture please let me know. God’s word is the final authority always overrules anything I might write. David
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4 Responses to Evolution Part 4– Natural Selection

  1. Freedomborn says:

    Hi David, I found your Blog by chance or was it planned, I will start with this Post and work backwards, it’s late so I may have to come back tomorrow.

    Your defence David for God’s Truth is commendable, and so is your knowledge of the unproven theory of Evolution. Sadly as far as Evolution is concerned, this has been a stumbling block not just for Atheists but for some Christians too, but God tells us in 1 Corinthans2 (9-16 ) those who don’t have the Holy Spirit are natural fleshy men and women and His Truth is foolishness to them. This is why they have to have a alternative but the only real evidence that they have and you shared it too, also confirms Creation but of course some have just been deceived like I was as a Teenager at School and by my Mother who is an Atheist.

    Perhaps they have never considered their belly buttons, humans are the only ones of God’s creation that have them like we do, Hummmm does make you stop and think but then perhaps they would invent a reason but of course as always have no proof.. Only God can create viable Life Secular Scientist have tried and failed for years.

    I came to the Truth about Creation when I started searching for the Creator and He found me.

    Christian Love from both of us – Anne.

    • dwwork says:

      Anne, thanks for stopping by. I once was a firm believer in evolution but about 15 years ago I tried to reconcile my belief in Jesus and evolution. As I did my research on evolution I found so many holes that I was forced to accept that what I had been told for years was just not true. Then I came on the intelligent design research as well as attending a seminar by Dr. Hugh Ross and saw that there was a reconciliation between science and faith that did not include evolution. Have a blessed day, David

  2. Allallt says:

    Dinosaurs evolved into mammals: citation needed.
    It’s not circular (and you know it). We know a species is specialised because of where in falls on the phylogenetic tree and it’s DNA. You know humanity still has the potential to diverge? H. G. Wells’ Time Machine is a chilling narrative when you think of it.
    The ‘junk DNA’ is, for the most part, genetic context for the other bit to work in. But junk DNA is not a phenomenon that -has- to be true under evolutionary theory, so it’s negation isn’t falsification. I forget who I’ve said this to (because I don’t pay enough attention to the Creationists I engage with), but evolutionary science outlines exactly what could falsify it: mammals in the pre-cambrian and irreducibly complex anatomy. “Complex” isn’t enough; it has to be “irreducible”.
    The classes are not pre-ordained; go back into the literature and tell me what class that Duckbilled Platypus or the Muskipper belong to. Not easy? No, that’s because it’s a human category and nature hasn’t been so kind as to completely conform to it.
    “Kind” does only beget “kind”. We agree here. But as “kind” can refer to any level in the taxonomic hierarchy (as Kent Hovind himself demonstrated by saying that “bacteria” was a kind [despite being as taxonomically diverse as “plants”] and “canine” was a kind [surely you see the problem here…]) the argument is nothing more than a description of what evolution is.

    • dwwork says:

      You said “Dinosaurs evolved into mammals: citation needed.” I will concede that I could have worded my statement better, mammals are said to have evolved from synapsid ancestors in the late Carboniferous period and the lineage leading to today’s mammals split up in the Jurassic. See here: http://en.wikipedia.org/wiki/Evolution_of_mammals .

      You wrote, “It’s not circular (and you know it). We know a species is specialised (sic) because of where in falls on the phylogenetic tree and it’s DNA. You know humanity still has the potential to diverge? H. G. Wells’ Time Machine is a chilling narrative when you think of it.” To which I reply, it is circular, what you have presented as proof is a phylogenetic tree which is nothing more than a chart of which I have found over 100 different variations and the magic words “it’s DNA” of which you provide no citations or how we can know that current species are too specialized to evolve into new kinds. Then you appeal to a sci-fi novel written in the 19th century. I am not sure what Wells’ novel has to do with this conversation except it is a great book which I enjoyed and yes it is scary for fiction. So I am left at the moment with your argument that species are specialized because they are specialized. If you can point me to some sources, papers or books that will tell me what makes DNA today specialized verses DNA from the past that was unspecialized so that macroevolution could take place I would appreciate it.

      You wrote “The ‘junk DNA’ is, for the most part, genetic context for the other bit to work in. But junk DNA is not a phenomenon that -has- to be true under evolutionary theory, so it’s negation isn’t falsification. I forget who I’ve said this to (because I don’t pay enough attention to the Creationists I engage with), but evolutionary science outlines exactly what could falsify it: mammals in the pre-cambrian and irreducibly complex anatomy. “Complex” isn’t enough; it has to be “irreducible”.” Actually mammals did not exist in the pre-Cambrian but their supposed ancestors did, see link above. Placental and marsupials are first found in the fossil record in the Jurassic period. Yes I would agree that finding that so called Junk DNA actually has uses does not falsify evolution I mentioned it because you brought it up and it seems to be a common theme in books supporting evolution. As to irreducible complexity, I will address that in a future post and yes there are irreducible complex biological systems.

      You wrote “The classes are not pre-ordained; go back into the literature and tell me what class that Duckbilled Platypus or the Muskipper (sic) belong to. Not easy? No, that’s because it’s a human category and nature hasn’t been so kind as to completely conform to it.” I agree all these classifications are manmade and have changed over the years. Who knows how the classifications will change in the future.

      You said ““Kind” does only beget “kind”. We agree here. But as “kind” can refer to any level in the taxonomic hierarchy (as Kent Hovind himself demonstrated by saying that “bacteria” was a kind [despite being as taxonomically diverse as “plants”] and “canine” was a kind [surely you see the problem here…]) the argument is nothing more than a description of what evolution is.” My point of course was that we see no evidence of macroevolution today. This seems odd since mutations still happen and I would think that we would see some new type evolving. All we see are changes within a species.

      Finally, if you want to refute an argument you might want to pay attention to what you have said to whom. This sounds more like a shotgun approach rather than an attempt to persuade someone to your point of view. It also shows a bit of a closed mind as well as lumping people into one category. As well as being condescending. But possible you cannot help being that way as you are captive to your DNA. I too was once an adamant supporter of evolution until, after much study, I found that actual evidence in support of macroevolution was lacking and much of what was presented as fact was conjecture and opinion or just outright fabricated. I do enjoy and appreciate your comments.

      Have a blessed day,

      David

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