|Feature Article - March 2001|
|by Do-While Jones|
We have a little unfinished business from last month. There were two questions about survival of the fittest that we deferred to this month. First, Chris said,
|Evolutionary theory states that species evolve to fill available ecological niches, not that species evolve to become "superior" (what is your definition of "superior" anyway?).|
Our understanding of the theory of evolution is that evolution is an unguided process. That is, it does not have a goal in mind. Evolution is not consciously trying to create more noble creatures. So, evolution does not produce creatures that are superior on some scale of nobility or importance. But the theory does claim to produce new species that are more fit for survival in the environment. According to the theory of evolution, these species are better at producing viable offspring in a hostile world because they outwit, outlast, or outplay inferior competitors. They are superior survivors.
Evolutionary Theory Arises from Scientific Observations and Conclusions Based on Them.The essence of the Darwin-Wallace theory is very simple; it consists of three conclusions based on four observations. Below we summarize their theory in modern terms.
Observation 1: Natural populations of all organisms have the potential to increase rapidly, because organisms can produce far more offspring than are required to merely replace the parents.
Observation 2: Nevertheless, the sizes of most natural populations and the resources available to maintain them (such as food and appropriate habitat) remain relatively constant over time.
Observation 3: Individual members of a population differ from one another in their ability to obtain resources, withstand environmental extremes, escape predators, and so on.
Observation 4: At least some of the variation in adaptive traits among individuals is due to genetic differences that may be passed on from parent to offspring.
A popular science book with a heavy emphasis on evolution by James Trefil puts it this way:
The central mechanism of evolution is natural selection. The basic idea of natural selection is this: at any given time there are variations in a population. Some giraffes have longer necks than others, some human beings can run faster than others, and so on. If certain variations give individuals who possess them a higher probability of surviving long enough to have children, then those characteristics are more likely to be passed on to the next generation. For example, if having a longer neck allows a particular giraffe to eat leaves other giraffes cannot reach during a drought, the giraffe with the long neck is more likely to survive the drought and have offspring. These offspring will resemble their parents and have longer necks. If the long neck remains advantageous, then over long periods of time giraffes with long necks will eventually become the dominant variation in the population. In this way, a characteristic that allows an individual to exploit his environment more efficiently comes to be shared by all members of that species. This is basically all there is to the idea of natural selection. 2
[emphasis in the original]
“Survival of the Fittest” doesn’t mean what it seems to. Natural selection is often characterized as “survival of the fittest.” Darwin himself used this phrase, but it is often misrepresented or misunderstood. Darwin used the term “fit” to describe individuals who are successful in producing offspring to the next generation, nothing more. In general, those individuals that are best adapted to their environment will be “fit” in this sense.
During the nineteenth century and persisting into our own times the notion of “fitness” was given a moral overtone by philosophers. It was argued that the “best” survive and prosper. As you see by the example of the giraffe this is not the way natural selection works. There is no moral judgment in nature. The only statement you can make is that those individuals whose genetic makeup gives them an edge in competition with their fellows are more likely to have offspring, so that at some distant time in the future those offspring will dominate the population. 3 [emphasis in the original]
This latter quote seems to be sensitive to the fact that evolution has historically been used to justify racism. In fact, the full title of Darwin’s Origin of Species is The Origin of Species by Means of Natural Selection; or, the Preservation of Favoured Races in the Struggle for Life.
Evolutionists have to walk a very narrow line. Their problem is that the proposed mechanism for evolution, namely natural selection, weeds out the inferior survivors and allows the superior survivors to reproduce. But in today’s society, any kind of comparison is seen as “judgmental,” and is not politically correct.
Yet, to Richard Dawkins at least, a squirrel with skin flaps is better than one without those flaps because it is better able to survive. He explains it this way:
|The way to think of the gradual evolution of something like a flying squirrel is this. To begin with, an ancestor like an ordinary squirrel, living up trees but without any special gliding membrane, leaps across short gaps. However far it can leap without the aid of any special flaps of skin, it could leap a few inches farther-and hence save its life when it encounters a gap of critical distance-if it had a very slight flap of skin, or a slightly increased bushiness of the tail. So natural selection favours individuals with slightly pouchy skin around the arm or leg joints, and this becomes the norm. The normal leaping distance of an average member of the population has thereby been increased by a few inches. Now, any individual with an even larger skin web can leap a few inches further. So in later generations this extension of skin becomes the norm, and so on. … After many generations, species like the marsupial gliders and the flying squirrels have evolved, capable of gliding hundreds of feet, and capable of steering themselves into a controlled landing. 4 [emphasis supplied]|
Notice how “it could leap a few inches farther” turned into “flying squirrels have evolved.” Somewhere along the line, speculation turned into fact. There is no proof, or even evidence, that squirrels gradually grew bushier tails and “pouchier” skin. There are no fossils showing this happened. Gradual development of skin flaps wasn’t noted by Aristotle or later intellectuals. Dawkins just thought that it was reasonable that it could have happened. Then, he convinced himself that it actually happened. It is entirely a matter of opinion. It is his personal belief that it happened. That strikes us as being closer to religion than science.
The only reason for believing that Death Valley plants became more tolerant of heat is an a priori belief in evolution. If you believe that all life started out from pond scum, then pond scum had to turn into something else, which turned into something else, which eventually turned into the plants we see today. According to evolution, they were better able to survive the harsh environment of Death Valley than their inferior siblings.
We didn’t just make that up. Environmental changes are often cited as the driving force behind evolution. It isn’t just park rangers that say it. It is the frequent refrain of those evolutionists who favor the “punctuated equilibrium” model of evolution. They think that rapid changes in climate spur on evolution. Here is one example.
|[Yale paleontologist Elisabeth Vrba] concluded that [particular shifts in fauna corresponding to particular shifts in climate] were simply part of a pattern that had repeated itself over hominid history. For example, it was about 5 myr [million years] ago that today’s familiar antelope species began to proliferate on the African landscape, an event that also coincided with an episode of dramatic cooling and drying, with a world-wide contraction of forests and expansion of savannas. And, of course, it quite possibly coincided with the emergence of the first hominid bipeds out onto the savanna. For Vrba, then, climate shifts have dramatically affected the evolution of the human family, but as part of a much larger picture: she sees periodic changes of this kind as the cause of general “pulses” of speciations and extinctions in which our own ancestors, as well as those of a vast variety of other organisms, were inextricably caught up. 5|
According to the evolutionary myth, our ancestors used to live in trees. On those rare occasions when they left the trees and walked on the ground, they walked on all fours. But then the climate changed, and the forests turned into grasslands. Those apes that were able to walk on two legs could see over the tall grass. They were better able to see danger, and find food. Therefore, they were better able to survive. Our inferior ancestors, who couldn’t stand on two legs, were less able to survive long enough to reproduce. Those genes that produced stooped-over creatures (which failed to reproduce before they died) were purged from the gene pool. Therefore, the combination of genes that produced a body better able to stand on two legs became dominant in the hominid gene pool.
|You also fall into the creationist habit of referring to life that is better suited to its environment than some other form of life as "superior." To quote: "If it really were true that environmental pressure stimulates evolution of new, superior life forms, then there would be nothing to worry about. More advanced creatures would simply evolve that would be better suited to the environment." Pond scum isn't more "advanced" than say, a bird. But if the earth were entirely composed of stagnant water it would be better suited to the environment. A tapeworm isn't more "advanced" than a person but it is certainly superior when it comes to existence inside an animal's intestine. Get with it! Scientists haven't equated evolution with the creation of "superior" creatures for many, many years. And in fact, the good ones agree that there is no objective measure by which we can gauge which form of life is more "advanced" than another.|
We don’t think some forms of life are “more advanced” than others. The notion of more advanced creatures is purely an evolutionary concept. People like us, who don’t believe in evolution, don’t believe that some species have evolved farther from the first, simple, life-form than others.
But evolutionists think in those terms. The current evolutionary story is that birds have evolved from dinosaurs. That makes birds more advanced than dinosaurs. They say that humans are more highly evolved, or more advanced, than apes. When they talk about “the ascent of man” (which was the title of a PBS series many years ago), they talk about how man has ascended from the “lower creatures.”
David claimed, “there is no objective measure by which we can gauge which form of life is more ‘advanced’ than another.” We agree. Since we don’t think living things have changed from simple life forms to more advanced life forms over millions of years, we certainly don’t believe there is any way to measure how much advancement has taken place. But evolutionary biologists do make comparisons of DNA, and based on those comparisons they try (often unsuccessfully) to draw the “tree of life” with the less advanced forms at the base of the trunk, and the highly evolved ones at the tips of the branches.
Although we don’t believe that any creatures are more advanced than other, it is possible that some creatures might be more complex than others. For example, bats may be more complex than bacteria. It is hard to rank creatures on a scale of complexity because it is difficult to come up with quantitative measurements of complexity.
Fortunately, it is unimportant to us. We don’t believe that simple creatures evolved into complex ones, so we don’t have a need (or even a mild interest) in sorting creatures according to complexity to try to infer their evolutionary history.
There is also a problem with telling good from bad.
Near the end of the Vietnam War, I heard a (supposedly humorous) story about two Vietnamese farmers. I forgot about it until I ran across a variation of it in a popular book 6. That author apparently heard the story differently than I did, and therefore used it to make a different point that isn’t relevant to evolution. The way I remember it, the story went like this:
First Farmer: I haven’t seen you in a long time. How are things going?
Second Farmer: My ox died.
First Farmer: Oh, that’s bad!
Second Farmer: No, that’s good because it forced me to catch a wild horse that is much stronger than my tired old ox was.
First Farmer: Oh, that’s good!
Second Farmer: No, that’s bad because my son tried to ride the horse and fell off, breaking his leg. Now he can’t help me with the crops.
First Farmer: Oh, that’s bad.
Second Farmer: No, that’s good because when the war broke out, all the able-bodied young men in our village were drafted into the army. Every one of them was killed in battle. But since my son had a broken leg, he didn’t have to go, and is still alive.
First Farmer: Oh, that’s good!
Second Farmer: Yes.
This story is relevant to our discussion of evolution because it addresses the question of whether or not there are good mutations. On our home page, we used to talk about “beneficial mutations.” Now it talks about "Creative Mutations".
The problem with that is that, like the first farmer, we can’t always tell good from bad (beneficial from harmful). Who would have thought that the death of the farmer’s ox would save his son’s life?
The issue isn't really "good" or "bad". It is more accurate to say that the issue is really whether there are “creative mutations” or not. Can mutations create a new body structure or a new capability that the parent creature did not have? For example, can an eyeless creature ever have a mutant baby that has eyes? We haven’t seen any scientific evidence that it can happen. Furthermore, what we are learning about genetics and information theory makes it so improbable that it is impossible.
Richard Dawkins tries to address this in his book, Climbing Mount Improbable, which we reviewed in the March 1997 newsletter. Dawkins’ problem is that every mutation must be immediately beneficial, or else natural selection won’t select it. Remember that natural selection has no long-range goal in mind, so it won’t keep mutations that aren’t beneficial now, but will be helpful in the long run.
In Dawkins’ example of the flying squirrel, each increase in skin area improves gliding, and presumably doesn’t hinder climbing. So, every mutation that increases skin area is immediately beneficial and would be favored by natural selection. Dawkins has picked an example where it isn’t impossible that all mutations could be beneficial. Even in this example, however, the mutations aren’t creative. The squirrel had skin already. It just became “pouchier” (to use Dawkins’ technical term ).
Trefil’s example of the lengthening of a giraffe’s neck also seems to show a series of immediately beneficial mutations, but it overlooks the negative aspect of a long neck.
|Due to the great distance between the animal’s heart and head, its vascular system is equipped with valves so that sufficient blood reaches the brain. 7|
If a giraffe did not have these valves, it would faint if it lifted its head too quickly. A long neck would be a disadvantage unless the valves evolved first. But since the valves don’t impart any immediate survival advantage for animals with short necks, there is no reason for natural selection to select them. Furthermore, these valves are new structures that didn’t previously exist, not modifications of existing ones. So, the evolution of the giraffe’s neck requires the evolution of novel valves, which serve no useful purpose before the lengthened neck requires them.
Evolutionists sometimes try to argue that there are neutral mutations that later turn out to be beneficial. It is true, a reptile with nipples could survive just as well as one without nipples, even if they didn’t have mammary glands. So, nipples might have evolved even though they served no useful purpose (and even though they impart no survival advantage). But natural selection would not favor non-functional nipples.
Someone might say, "Perhaps when the nipples evolved originally, they served some other, unknown, useful purpose. Then, when mammary glands developed later, the non-functional nipples just happened to be there, and in the right place, to conduct the milk outside the body." That argument is so silly that we feel uncomfortable just repeating it.
Yet that is really what evolutionists are saying when they claim that some neutral mutation later “adapted itself” to some useful, even necessary, function. It is a generally unspoken principle of the theory of evolution that neutral, creative mutations occur. These creative mutations have no immediate purpose, but will be useful (and necessary) to support some future mutation, or some future change in the environment. At least, that’s what they claim.
Evolution is not a guided process that has some ultimate goal in mind. It isn’t trying to create “superior” (that is fancier, more advanced, more important, or more noble) creatures. It isn’t trying to produce flying squirrels or long-necked giraffes. Therefore, it isn’t inclined to accumulate neutral mutations that can later be combined to create better creatures.
Evolution depends more on wishful thinking than science.
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Audesirk & Audesirk, Biology 4th edition (1996), p 311
2 James Trefil, Sharks Have No Bones, 1993 page 49 (Ev)
3 Ibid. page 55
2 Dawkins, Climbing Mount Improbable, 1996, pages 119-120 (Ev)
5 Tattersall, The Fossil Trail, 1995, pages 197-198 (Ev)
6 Carlson, Don’t Sweat The Small Stuff … and its all small stuff, 1997, pages 185-186 (Ev)
7 "Giraffe," Encarta 98. (Ev)