Evolution seems, at least in America, to have become one of the most controversial parts of science. It is a lightening rod for arguments surrounding religion. It is often a source for contempt for science, scientists, and the scientific method in general. For some people of religion, evolution is an important concept to refute. If evolution were accepted, then there may have to be a gradual realization that their god was not actually as much in control as they thought. Or at least some might have to admit to themselves that the Bible is not quite as literally true as they thought. This inevitably leads, at the very least, to a reassessment of one's faith or perhaps to an unraveling of the entire affair. These are understandably frightening thoughts for someone who has never known anything else. Sadly, many students are not exposed to proper science instruction, including evolution, in schools for fear of the very things mentioned above.
If you already understand and accept evolution, then this page is unlikely to be of much use to you. If, on the other hand, you have been brought up in a religious environment that has been distrusting of scientists and evolution, or if you believe that humans, animals, and plants are the way they are because God created them that way, then you may find this page helpful. Even if you reject evolution after having learned about it, at least do learn about it. This page may help as a very basic level of introduction to understanding evolution.
When conversing with religious people, usually Christians but sometimes people of other religions, it has been my observation that there are two unfortunate constants in their view of evolution. Firstly, the conclusions are drawn before the evidence is examined. The conclusion that the earth is young, and that God created it is not negotiable. Therefore, any evidence found to question that conclusion must be explained away. (Here we get into the issues often raised by evolution-deniers ranging from the inaccuracies of carbon dating and the Piltdown Man hoax to the notion that all scientists are in on a vast conspiracy to disprove God). Secondly, I find an astonishing level of ignorance and lack of education about evolution. On occasion in discussion with someone who denies evolution I have asked them to simply give me a very brief overview of what evolution is. Almost without fail the person in question either denies the request or fails to properly answer it. Often, in attempt to explain evolution, there is reference to the notion that humans are descended from monkeys or that, since humans now exist, if evolution were true then monkeys should not also continue to exist. This astonishing level of ignorance about evolution is a shame, and it also partly explains why there is such persistent mistrust of evolution. With such an interpretation of evolution, I would likely reject it too.
If you don't believe in evolution but are an open minded person who actually cares about the truth, consider reading on and learn a bit more about evolution. Understand the basics of it. Go and read about it elsewhere with an open and critical mind. No scientist ever wants someone to accept their work uncritically. Education should be a never-ending process in life, and it is amazing how your world view can change once you realize where we humans came from. But, if you are are going to undertake this educational process honestly, then you must have an open mind to the possibilities. You must learn to examine the evidence in an unbiased way before you form any conclusions. Evidence is easy to explain away if you have already made up your mind about something. Try to resist doing that.
Charles Darwin
Darwin was an English naturalist who lived from 1809 - 1882. His life spanned a time when the British held massive influence and power in the world and covered most of the globe with their empire. In particular, the British were a very strong seafaring nation. Darwin's most famous voyage was taken on a ship called the Beagle starting in 1831 for almost five years. The Beagle circumnavigated the globe charting coastlines and Darwin spent a good deal of that time on land in various parts of the world observing nature.His most famous stop was in the Galapagos Islands on the West coast of South America.
Upon his return to England, Darwin eventually published his observations and his interpretations of his observations. His scientific method was quite different from today's laboratory-based scientists, but his finding was almost certainly the greatest biological discovery ever and perhaps the greatest discovery in all of science. For, eventually Darwin managed to begin to answer some fundamental questions that almost every human must have asked at some point. Questions such as: "Where do we come from?"; and "Why are we here?"; and even "What purpose do we humans have?"
There were others that were critical to the development of evolutionary theory but, as often seems to happen in history, one individual gets all the glory and in this case Darwin seems to typically get all the glory (or demonizing!).
Basics of Evolutionary Theory: Survival of the Fittest
Essentially, Darwin's observations were the following. Life requires resources. Chief among these are typically food and energy. There are a limited number of resources available. Sometimes a population of species might seem like it has unlimited resources, but eventually they resources will run thin. When this happens, there is competition between individuals of the same species for the same resources. When there is competition, not all the individuals of a species will survive to sexual maturity. When individuals do not survive to sexual maturity then, by definition, they do not reproduce. Individuals that happen to possess traits that allow them to be more successful in competing for resources are more likely to survive to sexual maturity and reproduce. Since offspring typically resemble their parents, the offspring will then also be likely (but not necessarily) to possess the trait that gives them an advantage in competing for limited resources. (This is the infamous "survival of the fittest" part of evolution that is often misinterpreted to mean fitness in the specific human way. Fitness might be as simple as a plant possessing slightly more chlorophyll in its leaves).
A "Totally Random" Process
Other much better writers than I have covered this topic much better than I could. But, as a brief introduction to the topic, the random processes involved in evolution often seem to generate problems for people in accepting the whole theory. Although evolution involves some chance and random processes, it is not a random process that occurs by chance. This is another infamous sticking point for many people. The attempted analogies a "random evolution" are both numerous and inappropriate. A tornado going through a junkyard and assembling a Boeing 747 by chance; walking along the beach and finding a watch indicates that the watch must have been designed by someone. These are common analogies used as arguments against evolution by those who have already decided to reject evolution without understanding it. If you understood evolution, you could not make such analogies with intellectual integrity. Evolution, though it involves chance, is a very orderly process with somewhat predictable results. Though we cannot predict where evolution will take species in the future, we can make predictions about the process: it will continue to result in adaptations as a result of competition for resources; those with traits that make them more competitive for resources are more likely to survive to sexual maturity and reproduce.
So, what part of evolution involves chance? Reproduction is not perfect. Offspring are not perfect genetic photocopies of their parents. Sexual reproduction, of course, results in offspring that are not identical to either parent but which possess some traits of both parents (to simplify it a bit). Asexual reproduction more usually results in offspring that are genetically identical to the parent. But, in either case there are imperfections in the reproductive process. DNA is not always copied perfectly. Occasionally, random mistakes are made in the process of replicating DNA. Often these random mistakes have no effect whatsoever, or at least no effect on the phenotype (the displayed trait of the gene) off the individual. Sometimes they have negative effects resulting in a non-viable offspring that doesn't survive even to birth. Sometimes they have effects that are either "negative" or "positive" in life. Perhaps a genetic variation results in a slightly bigger nose. This may have no effect on a human, but it might slightly alter an elephant's chances of surviving to sexual maturity, reproducing, and helping its offspring in turn survive. Over massive amounts of time that are too long for the human mind to properly appreciate, these small random variations tend to make a difference in the traits represented in the particular species. For example, over many tens and hundreds of thousands of years, those elephants with slightly longer noses are going to be better suited to survival compared to those elephants with shorter noses, especially in times when resources are scarce. So, eventually, given that long-nosed elephants are more likely to survive and reproduce (thus giving birth to longer-nosed elephants themselves), the population of elephants may tend to have longer noses than they did in the past. To understand the evolutionary process, one needs to keep in mind that this process is constantly happening in all genes and that the changes take place over enormous stretches of time. We humans are probably virtually identical to humans that existed a handful of thousand years ago. But go back 150,000 years and you'll find a significant difference. Significant enough that they can no longer be called the same species. So, the process does involve some random chance, but the overall process of evolution is anything but random. Daniel Dennet has described the process as a very slow ratchet, gradually raising the traits of a species over many thousands of years.
The process of evolution can, at first, seem unrealistic to the human mind. We deal with a minuscule lifespan on the evolutionary timescale. Our mind can comprehend and relate to a lifespan of 70 - 80 years, or even to a longer time span in history such as a few hundred or even thousand years. But the time scale of evolution is huge. Evolution takes place over millions of years, and across billions of individuals within a species. The adaptations in a species might seem so small and slow that the whole process seems unreasonable. But one has to remember the massive amount of time with which evolution has to work. An analogy might be looking at the odds of winning a raffle draw. If you pay to enter a raffle lottery with 5,000 tickets, you may think your odds of winning the grand prize are ridiculously small. If you picture yourself standing with 5,000 other people watching someone dip their hand into a big bowl of all the tickets. The chance of you winning is only 1 in 5,000. Pretty slim odds and you're very, very likely to walk away disappointed. But, now imagine that you are in the raffle draw every single day of your life. If you lived 70 years, you would be involved in over 25,000 raffles. Each time the raffle is drawn you still only have a 1 in 5,000 chance of winning, but you get those odds over 25,000 times. You may still not win, but the odds are pretty good. Evolution is a bit like that analogy. The odds of a genetic change that provides a competitive advantage in one generation is small. And, any change that does occur in one generation is almost immeasurably small. (I say "almost" because there would have to be some measurable competitive advantage in order to increase the odds that an individual survives to reproduce compared to its peers). But, over millions of years, the process becomes not only measurable and observable, but also inevitable. You may also be tempted to think that if there is almost no measurable difference in competitive advantage (or "fitness") of an individual, then any increase in their probability of surviving to reproduce as a result of that advantage would be overwhelmed by other factors. Indeed it would, in that individual. In the example of elephants with longer trunks being at an advantage in feeding, in a small population of elephants, those with longer trunks may not actually be measurably better at surviving to reproduce (because of other factors involved in the death of elephants such as disease or drought), but in a population of hundreds of millions of elephants stretching over a time span of millions of years the advantage of having a longer trunk becomes not only measurable but inevitable. Those elephants with longer trunks will inevitably be better at surviving than those without. This point is the crux of why evolution seems so unbelievable to some of us. When you forget about the time scale then it is unbelievable. But when you massively increase the odds by looking over millions or even hundreds of millions of years, then it does work.
Why Are There Still Monkeys?
Did we come from monkeys? No. Evolution does result in splits of species as well as adjustments within a species. Species can be found to have a common ancestor species back in time, and some species are more closely "related" than others in the sense that their common ancestor is relatively recent in time, such as chimpanzees and humans. Further back in time humans have a common ancestor with other primates such as gorillas and monkeys. But that is not to say that humans are descended from chimps, monkeys, or gorillas. Humans did not evolve from monkeys. Humans and monkeys are branches of a closely related part of the evolutionary tree. We each branched off from a common ancestor and went in different "directions" (in other words, through genetic variation started to show more and more different traits). And the common ancestor has long since gone extinct. So, humans and monkeys never were part of the same species directly competing for the same opportunity to reproduce. {And here we should mention another major factor in evolutionary drive which is that there are not only limited resources for a species, but there are limited opportunities for reproduction. Particularly in sexual reproduction, not every individual can find a mate to reproduce with. Therefore, those individuals who are at an advantage will not only be more likely to survive to sexual maturity, but will also be at an advantage to compete for a mate over other less competitive individuals). Because humans and monkeys are not directly competing for the opportunity to reproduce, their ability to reproduce and propagate the species is independent of each other. Therefore, asking the question: "If there are humans on earth then why are there still monkeys?" becomes nonsensical. The two are not in competition. A more relevant comparison might be to look at why Neanderthals and Cro-Magnons did not co-exist for very long (perhaps 10,000 years). These two hominid species were likely in competition with each other, and Neanderthals died out relatively quickly (in evolutionary time) when Cro-Magnans appeared.
Evolution Doesn't Happen Anymore, Does It?
Evolution is an ongoing process that seems to continue unabated. The rate of changes may alter, but the process in general doesn't seem to halt. There is debate amongst scientists about whether there are periods of vast change through evolution followed by periods of relative stagnation, or whether the rate is unchanging. The former seems plausible to me, given that there are likely to be catastophic events on our planet from time to time that dramatically alter the environment to which species are suited (e.g. large volcanic eruptions of meteorites such as the type of event that wiped out the dinosaurs). But, nevertheless, given the right conditions, evolution is an ongoing process. It is tempting, trapped as we are in the small human mind that considers time scales of 70 odd years rather than millions of years, to think that evolution happened and resulted in us. But, it will carry on. One day, assuming the planet itself and life continue, humans will not exist anymore and many other species that are not currently in existence will be.
One of the better long-term experiments demonstrating evolution in a time scale that we can comprehend has been conducted by Dr. Richard Lenski. Dr. Lenski has studied evolution in the bacteria E. Coli since 1988. Over the past 23 years the experiment has observed over 10,000 generations of bacteria, allowing the obseration of evolutionary change in these organisms in a compressed time scale that we can appreciate and study. In humans, the same number of generations would take about 2,000 centuries (200,000 years) given a rate of reproduction of 5 generations per century (given an average age of reproduction of 20 years, which is reasonable enough if you were able to study humans either in a "controlled experiment" or throughout most of our primitive history). I won't go into Dr. Lenski's findings here, you can easily look him up if you are interested in the details, but suffice it to say that evolution is alive and well in the thousands of generations of E. Coli reproduction. Some startling changes were observed in the metabolism of these organisms over time.
Why Does Science Matter Anyway?
In North America in general these days, there seems to be a common culture that science really doesn't matter that much. Some view scientists as out of touch academics who don't really work in the real world. Science may have brought us some neat things in the past, such as flight, surgery, and insulin, but we don't really need science as a part of our society beyond knowing that somewhere in a lab men and women in white lab coats are slowly working away on things like finding the cure for cancer.
What is science? It is the process of discovery. In the infancy of our species, we clearly knew very little about the nature of the world around us. "Cavemen", so to speak, didn't know what lightening and earthquakes were, they didn't understand plant reproduction, they didn't know what caused disease. Even in relatively recent times people thought the earth was flat and the sun orbited the earth. Science, as a process, is responsible for ALL of the discoveries we've made as a species. Though primitive human societies may not have included professional scientists who spent their careers carefully uncovering the truth about the natural world, yet small discoveries that made life easier were all made through the process of discovery. Someone discovered that fire is a useful tool for cooking food. Someone discovered that putting a round object underneath a heavy object helps you to move it along the ground. These are all scientific discoveries. Other attempts at scientific explanations of the natural world included thinking that Poseidon was responsible for ocean behaviour, and that lightening was the will of Zeus or some other god. Though these turned out not to be true (because the process of science was not conducted very well), yet they were attempts at discovery and explanation of the world around us. So, attempts to explain the natural world sometimes lead to faulty conclusions. This is an inevitable part of the process of discovery, given our faulty biases as human beings combined with our limitations in technology and information gathering. The important part of the scientific process is knowing how to avoid drawing incorrect conclusions in the first place, and knowing how to recognize them when you do so. In this way the scientific process itself is responsible for self-correction. Yes, scientists make mistakes. Yes, they can be wrong. Yes, some scientists even deliberately misinterpret data and draw faulty conclusions. But the process of science, if adhered to properly, will eventually always uncover such errors. Fundamentally, that's all science is.
So, why is there such disdain for science and scientists in some parts of our culture? I don't have the answer to that, but I do think it has something to do with our current lifestyle which is very much cut off from the natural world. Consider one of the more rejected parts of science: ecology and climatology. One can barely bring up the term "climate change" in a social gathering without invoking some serious eye-rolling at the least and perhaps even a heated argument. Almost undoubtedly, someone will talk about how irrelevant that whole topic is to our lives. People are more concerned with gas prices, keeping the fridge stocked with food, running the kids to daycare, and saving up for a vacation to be worried about environmentalism. That is the perception but I believe it completely ignores an inescapable fact: we are an animal species that lives in the natural world. We are as much hostage to the rules of the biological world as any shrew, eagle, dolphin, or ant. Just as those species require a certain environment for survival, so do we. It just so happens that our environment has changed to the modern suburbia where we are so cut off from the natural world ("Mom, where does milk come from?") that people forget we are hostage to that natural world. Without water and food we all die. We think we have established a society in which water is accessible at the turn of a faucet, but is that a sustainable lifestyle? Maybe. Maybe not. We will see in the future. Certainly it is not sustainable if population growth continues unabated.
I have digressed a bit, and I don't want to turn this into an environmentalist rant. That is not my purpose. My purpose is to point out, as an example, how the science surrounding our environment (remember that every species has an environment with certain requirements) has been completely ignored, misunderstood, and even rejected.Why? Because people have not educated themselves on that science, to our peril as a species. I am not a doomsday theorist who says we have to radically change our lifestyles or the world as we know it will end. I am, however, a scientist who recognizes that there are consequences for every action, and that there are a limited number of resources in our world. It should seem obvious to anyone that we cannot sustain an indefinite growth of population. Eventually, something has got to give.
So, ignorance of the scientific process seems like a common theme in our culture. "It just doesn't concern me." seems to be a common attitude. Granted, not everyone needs to be a scientist, nor even have a large understanding of science. But, in my opinion, everyone needs to have a healthy respect for the fact that the scientific process is critical to our species. We would quite literally still be living in caves (if we as a species actually ever did so - it seems much more likely we lived on the Savannah than in caves) if it weren't for science. It may be tempting to think that that is all in the past. We now have modern medicine, automobiles, aircraft, computers. Science has done a good job, thanks, now let's move on. But, the reality is that we are still very ignorant of our natural world. We may have made huge increases in knowledge in the past few thousand years, but what we do know is still minuscule compared to what is left to discover. The week that I am writing this I noticed two news stories in the science and technology section of a news web page. The first was about the discovery of a pulsar with an orbiting planet made out of diamond. The second was the discovery of a huge underground river several thousand feet below the Amazon. Both of these struck me as small examples of how much is left to discover about the natural world. Why do we care about these discoveries? Well, the underground river discovery is an example of how we don't yet really understand our place in the global ecosystem. We think we know where our water comes from and where it goes when we're done with it, but we really don't. That there could be a huge underground river moving similar amounts of water as the vast Amazon River that, until now, we were completely unaware of, is astounding.
So, ultimately, science is very important to all of us. Without science we would completely stagnate, or even drift backwards. Some people seem to have the attitude that "good science" is worthwhile but that there is a lot of wasted money and time on science that doesn't help anyone. Some think that things like cancer research should be funded publicly, but the study of small worms that inhabit ocean floors is not. I think many non-scientists think that much scientific work is esoteric and ultimately useless. The fundamental problem with this attitude is that you are not able to pick and choose what you're going to find when you go no a voyage of discovery. Many of the greatest scientific discoveries in history were made by accident, or at least with the scientist involved not planning on finding what they found. (Indeed, when you go on a voyage of discovery, how can you know what you expect to find?). Cutting out some science as "useless" is to miss the whole point of scientific discovery. If we don't study ocean floor worms, we may never discover that the cure to cancer lies within their cellular metabolism It likely doesn't, of course, but it is possible and without pursuing discovery of ALL of nature then we risk missing the biggest and most valuable discoveries of all. An example of this is the discovery of penicillin, quite by accident by Alexander Fleming. If Fleming had been ordered by society to pursue only "worthy" scientific discovery, we would likely still have no means to fight bacterial infection. Science, by its very nature, comes as a complete package. All or none.
Why is Evolultion Often Seen as a Debated Topic?
Why even have this page? Why the need to explain evolution at all? That's a good question, and in an ideal world scientists would not need to spend any more time discussing and explaining evolution than they would with any other scientificaly accepted reality. Evolution is as accepted in science as pretty well any other issue. Amongst bona fide scientists, there is simply no more debate over whether evolution happens or not because all the evidence supports it. It is in the same class of issues as the fact that our solar system is heliocentric, or that gravity exists. So, why the need to keep discussing evolution? Why do I devote an entire separate page on this blog to the topic? Because there is a concerted and organized effort to discredit evolution and to bring debate to the issue, and therefore scientists find themselves in the position of having to waste time defending hte basics of evolution, which has been scientifically established for over 150 years. Why is there this organized effort to discredit evolution? Because evolution threatens the existence of God, simple as that. Almost everyone who challenges the basics of evolution has an agenda or a religious position that is threatened by the facts of evolution, and they need to try to discredit it in order to preserve their position. This is exactly analogous to what happened between scientists and the Catholic church as we discovered that our earth is round and orbits the sun. The Catholic church and its perception of God were challenged by this scientific discovery, and so they rejected the evidence, discredited the science behind it, and persecuted the scientists who were making the discoveries. This is exactly what is happening in modern times with evolution. The evidence is being ignored, the science is being discredited, and the scientists who are responsible for the discoveries are discredited and persecuted (think of how much Darwin has been demonized in creationist circles in America).
Eventually, of course, the Catholic church had to accept the heliocentric nature of the solar system. We can have hope that the same may happen with evolution. Eventually, we can hope, religious groups may alter their point of view and accept the facts of evolution. Some religious groups have done this and fit their model of God into the facts of evolution. We have all heard of Christians who talk about God using evolution as a tool he used to create the world. This position is sort of a reluctant and unrealistic acceptance of the facts of evolution, and it makes the massive mistake of trying to fit the evidence into an agenda (a major flub that leads to massive errors in the scientific process), but at least this position reluctanctly accepts the facts of evolution. Unfortunately, however, it seems that more and more people are going in exactly the opposite direction in the United States especially. More and more people are trying to keep the science of evolution out of schools and "teach the controversy". Sadly, some people simply can't allow their preconceived notion of a deity to be threatened by the reality of the world we live in.
What Evolution is Not...Common Misconceptions
Evolution is Not Random
The most common misconception about evolution is that it is random and that it all just happened by chance. A little bit of knowledge, as they say, is often more dangerous than complete ignorance. In this case, a little bit of knowledge that the process of evolution does involve some random events is dangerous because, without a more complete understanding of how chance fits into evolution, one is likley to just reject the whole thing. As explained above, there are parts of the process of evolution that involve chance. As DNA replicates, and as species reproduce, different, random phenotypes appear. Which types of things change in offspring is somewhat random (maybe not in a specific case of reproduction, but overall in a population there is some randomness and chance involved). If you have brown eyes and your mate has blue eyes, you might have a brown eyed child or a blue eyed child. There is a certain amount of chance involved. You could figure out the odds if you knew your particular genetics. But, once you have a blue or brown eyed child, the effects of having blue or brown eyes on their chances for survival are not so random. If they live in an environment where having brown eyes is an advantage to survival, then they will be more likely to survive to adulthood (and reproduce themselves) if they do indeed have brown eyes. Therefore, in a large population of this case, brown eyes will tend to dominate and evolve. So, the process of whether an individual inherits that particular trait has some chance involved. You might be justified in saying that it is just chance that your child has brown eyes. But, the overall process of certain populations having brown eyes as completely dominant is NOT random.
There is a common theme among those that reject evolution to look at the end product and question how it could have just come about by chance. (How could a tornado go through a junkyard and assemble a Boeing 747...). But that position overstates the chance component of evolution. That question is the same as saying: "If there is a 50/50 chance of your kids having brown eyes, then it is not realistic that all the population, just by chance, has brown eyes." There may well be a 50/50 chance in the single reproductive event, but overall in the process of evolution, it is inevitable that all the population (in this particular example) would have brown eyes.
Evolution is Not a Tool That God Used to Create the World
Many more liberal Christians accept evolution as a process because the evidence so strongly supports it, but can't allow their acceptance of evolution to challenge their preconcieved belief in God. Many Christians fall into this category in which they accept that evolution happened and that the earth is billions of years old, but then they turn around and claim that it just shows how amazing God is for using evolution to creat the world. This is incorrect on a couple of counts. Firstly, evolution is a scientifically supported process. Suddenly, and without evidence, introducing a deity into the process is wrong. It is not scientific. You can't accept evolution because of the scientific evidence for it, and then step outside of science and just tack on a deity to the process because you are unable to let that deity go. Secondly, evolution does not, of course, explain the origins of the universe, the solar system, the earth itself, or even the very first orgins of life itself. There are other scientific theories about that, but evolution describes the process by which species develop and change. One might claim that God used evolution to end up with humanity from swamp bacteria. But, that ignores the facts of evolution which show that it does not inevitably lead to intelligent life or to a "super-species" such as humans. If the whole thing ran through again, humans would almost certainly not exist. A stray meteorte here, a plague there, and the evolutionary process would brought us to the modern world with a very different colleciton of species. (Or, more likely, lack of a stray meteorite would have resulted in a modern world still dominated by the great lizards).
So, evolution is not just a tool that God used in his wondrous plan for humanity. That idea elevates humans well beyond our importance in nature (as does religion in general), and disregards the parts of evolution that are random.
To be continued...
