HOW EVOLUTION NATURALLY SELECTED ME
If you’re anything like me you think Radiohead is the greatest band on the planet; that the Rolling Stones are important, but overrated; Natalie Portman is the greatest actress of her generation (and hot, even with short hair); the most disgusting noise is the noise of someone eating with their mouth open; and you read—a lot. But no fiction, only non-fiction. Not even James Frey non-fiction. A lot of it is news, some of it is commentary, and sometimes life experience. I read a lot about Intelligent Design (ID) these days. It’s not something that I’m particularly proud of, it’s just hard not to. It’s like a train wreck. Can’t…look…away…
The truth is I find it difficult to read about ID because of my background. It makes me question whether what I have been taught is truth. I am very skeptical. This doesn’t help me scoff at arguments easily, as so many others do. I have to analyze and spend hours considering the truth. In this day and age, it isn’t easy. Truthiness surrounds us.
Recently, I was at a party in which an old friend of mine informed me that she didn’t believe in evolution. My first thought was, how is that possible? I have known her since high school, in fact, we were in biology together. We both grew up in Calgary, and although there are many similarities between Alberta and certain American states, I did not figure that she could not believe. We were both in the Alberta Catholic school system, which, I informed her, actively believes in evolution (a statement direct from the Pope). She wanted to know what I thought about evolution and how I could be so certain that it was correct. I began to panic a little. The ID people had gotten to her. It’s like a secret organization. They are mocked and ridiculed by the mainstream, yet secretly they are among us. How could this be? She was a normal everyday engineer. Really that’s a lie. There are no normal engineers. But she had a basic background in biology. By not believing in evolution, does that mean she doesn’t believe in biology as a science? What if she’s on to something? Wait. Don’t jump ship yet.
I accept evolution because if I don’t, a lot of biology doesn’t make sense when you’re studying for it. But evolution is really challenging because it isn’t easily visualized, nor is it easy to accept unless you know a lot about it. I sometimes feel this to be the problem with ID proponents. They haven’t seen the evidence, often have no desire to see the evidence, and therefore, cannot believe in evolution. I read anti-evolution websites to see what these people are all about. They are very technical and full of evidence. After a little while, it makes me question what I know. I had to look back and examine the evidence and my own uncertainty.
Most people think of Charles Darwin when they hear the word evolution, however, the term has a complex scientific history as many different fields have used it with different meanings. In fact, Charles Darwin’s pivotal Origin of Species (1859) does not use the term evolution. In the 1850s the term began to take on its modern meaning as the “theory of transmutation of species.” Sort of. Geologist Charles Lyell is often attributed as one of the first to use evolution in its modern sense. But at this time the term was defined by a sense of progress, which is a big no-no in evolutionary theory. Eventually, evolution came to represent a process by which novel traits are inherited by future generations, and over time new species are formed. That’s pretty straightforward, but in the context of the nineteenth century Judeo-Christian world this was earth-shattering. Not in a Red Sox win the World Series kind of way, but in a much bigger, question your God kind of way (although for Sox fans, there is no bigger). It was a tough hundred years or so for God (and his followers). First, the French and their crazy deistic ideas, then geologists like James Hutton and Lyell claimed that the earth was much older than a few thousand years and that life was subject to uniformitarianism, and finally, a guy with mutton chops and in a desperate need for an eyebrow grooming, claims that species are created by random, non-progressive events.
Uniformitarianism is an important concept to biology, because it claims that natural processes occurring presently, also occurred in the past. This allows scientists to assume that processes like continental drift, and more importantly to Darwin, evolution, have been occurring since the beginning of the earth. Darwin is important to biology for theorizing on the mechanism of evolution⎯natural selection. His theory states that traits that allow individuals to survive and reproduce will be passed along to future generations. Over time, this process can lead to new species. One stipulation of Darwin’s theory is that natural selection is not progressive. It is random. Mindless. Animals don’t just become more intelligent or more complex, they can become stupider, slower, blinder, and less limb-y, as long as reproductive success is maintained (or enhanced).
Evidence for evolution is a hard sell. It’s like asking someone how they believe in sharks, if they have never seen one. Well, I infer. Besides the fact that monkeys really look like humans, and that birds, horses, fish, mice, bats, and humans all have equivalent bone configurations, medicine provides examples. Bacterial/viral resistance which is a great problem today, is an example of natural selection at work. But I guess there are people that don’t believe in medicine. Also, ID proponents would argue that adaptation may occur, but this does not give rise to new species. The problem with this argument lies in the uncertainty of biologists. The lack of a solid definition for the term species makes this a difficult argument. Some would consider new bacterial strains different species. But with an obscure definition for species, when is a species no longer the same species as it once was? In modern biology we can use DNA analysis to provide insight. But to look further into the past requires fossils.
ID websites like to use the lack of fossils as support for the impossibility of evolution. First it is important to note that not everything is fossilized. Fossilization requires special conditions. For example, a dying dinosaur needs to be somehow saved from decomposition. Dying at the bottom of a lake or a tar pit can help this. Over time the remains are mineralized, and later in time dug up by a grad student. Maybe a summer student. Digging is hard work. And another important note is that hard tissues have a better chance of fossilization. Boney animals can often be tracked in the fossil record, but animals like sharks or squid, have a hazier history.
The fossil record also indicates a punctuated type of speciation. Stephan Jay Gould and Niles Eldredge, proposed a theory of punctuated equilibrium to explain this. The theory more or less states that for long periods of time little happens, then there are bursts of new species. The formation of new species likely occurs from smaller isolated populations, while any changes in large populations are diluted and less likely to form new species. These new species are less likely to be found in the fossil record unless their populations increase in number. Isolated speciation like this can explain how certain species seem to change quickly (e.g. among the human lineage) while others take more time. Because of isolation, adaptations can occur quickly, thus, evolution often occurs faster than people give it credit for.
What of transitional forms, the proverbial missing links? There are many examples of transitional forms in the fossil record. Fish, fish with lungs, fish with leg-like parts, fish-like animals that are likely not fish but amphibians. This concept of missing links is tricky. Generally, missing links in the fossil record are present between larger groups, but missing at the species level. So we may not know who our direct ancestor was, but we do have evidence of many bipedal human-like animals. Transitional forms are kind of awkward. They have developed certain adaptations, usually to improve energy efficiency, but these adaptations don’t necessarily provide direct advantages in reproduction or feeding. So they are not seen in great numbers, and less likely to be fossilized. An example is the reptilian feather. Although they are useful for insulation, it isn’t until they can be used for flight that they become helpful for reproduction/feeding.
The most convincing observation in the fossil record to me, is that when there are changes in climate (for example when the earth heats up) new life explodes on to the scene. And for all the new plants that are born, there are a number of odd looking animals that join them. This often occurs when there are mass extinctions as it frees up niches. It’s like if all the polar bears in the world died (which may happen sooner than later…), all the fish, seals, and belugas that they eat would increase in number. Eventually, something would come along to exploit this food source. This brings up an interesting point, ever notice how everything has something that will eat it? To me this is a great example of evolution, the fact that things eat nuts, grass, carbon dioxide, poop, dead moths, bacteria, and any other biological by-product. Even urine is useful!
Another difficulty often cited is the process of examining fossils. How is it possible to tell how a dinosaur walks from one bone? Well, as a biomechanist, this question is particularly interesting to me. Important bones, like femurs or skulls, have attachment points that let us determine the size of muscles. This allows us to infer, for example, that a certain dinosaur had major jaw crunching power and was likely a carnivore. This can be further ascertained by the discovery of teeth.
Questioning bones brings up another important concern, what if you don’t look like your ancestors? If you didn’t have your grandfather’s nose how would people know that you were related? Crocodiles fall into this category. That’s because their ancestors likely lived in a terrestrial environment, unlike current, semi-aquatic crocodilians. Since crocodiles have a low body form and their ancestors may have been bipedal, their lineage can be determined by looking at features that don’t change much among reptiles. To this, scientists look at holes in the skull. These holes can tell them which reptiles are most closely related as these skull holes shift and change shape across reptile groups. By looking at these characteristics scientists (with the help of computers) can determine which bones are most closely related, and thus part of a lineage.
A problem often cited by ID websites is the nature of complex adaptations. They claim that there are adaptations that are just too complex for evolution and therefore, must be due to a Creator. But evolution is not always as it seems. For instance, a jaw is a complex adaptation that was initially used to increase ventilation and eventually led to more efficient feeding. Moving one adaptation at a time or through a system of co-adaptations, complex traits can be developed. Darwin was afraid of the eye as it was a true challenge of his theory. How could something as complex as an eye form through the random nature of selection? As long as a reproductive advantage is offered, anything that our DNA backbone allows is possible. This is evidenced by the many different eyes that have developed. Humans, insects, fish, octopi, and snakes all have different eyes. In fact there is a spectrum of animals that have ‘eyes’ that represent the stages that would be required for eyes to develop. The slightest form of an eye, a light-sensitive patch, would be helpful in determining the direction of the sun.
An important development in this research is that eyes seem to be created from a set of genes that are shared between all animals. So although they keep popping up independently, eyes may be constrained by the genetics of animals. So that means that they follow some intelligent design, right? This isn’t really new, since limbs and body segments are often similarly conserved. Interestingly, the variations in eyes seem to go against intelligent design. If you were an intelligent designer wouldn’t you want to create the most efficient eye possible? In this case the human eye is flawed, in the sense that light has to travel through a layer of non-light-sensitive cells to reach the light sensitive retina. The more efficient (and intelligent) arrangement would be to reverse the situation so that light is optimized. This type of eye is seen in squid and octopi.
In the end I believe in evolution because of what I know. But I guess people who don’t believe, don’t need to know. Ignorance is frustrating. The problem with ID is the same as the problem with truthiness in general: it’s truthy, not facty. There is no real debate here, just selective use of facts. For rational believers, it’s easy to believe that God created the driving force for evolution—natural selection. Science is a funny thing. It’s a little like math, where knowledge is built one step at a time. Simple followed by complex. But unlike math, science that you were once taught in the beginning may not be true. It’s like finding out later in life that two-plus-two does not equal four, or sometimes it’s not entirely four. Thus, students are taught the prevailing theories of the scientific community. This means that for a particular subject this is the best information that the scientific community currently has to offer. Theories can be wrong. That’s why they are called theories. And thanks to the handsome Austrian Karl Popper, we know that we can never prove a theory to be true. But uncertainty is always looming above it, because a single unexplainable observation can disprove a theory. But more often than not, it just changes a model and the theory is altered to make sense of the rogue observation. ID supporters like to say that ‘evolution is just a theory.’
As Stephen J. Gould wrote, “In American vernacular, ‘theory’ often means ‘imperfect fact’…” Gould was particularly bitter because his words were often cited as support for the lack of evidence for evolution, when the truth was that he was just uncertain. These arguments are annoying because they allow individuals to conclude that an expert like Gould is misinterpreting his own results. He claims to still believe in evolution despite the fact that he does not have sufficient evidence. So if you’re like me and you read things that go against what you know, don’t be a victim of your uncertainty. Uncertainty makes science possible. It’s a helpful check, so that scientists don’t blindly accept theories. Others can use your uncertainty against you, but it’s really because they don’t know the facts.