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In a quick review, I would like to discuss the website by Lin and Don Donn, http://earlyhumans.mrdonn.org/evolution.html.
This website is part of a much larger website that is filled with a lot of information on all sorts of history. As Mr. Donn states, they do not claim to be experts in anything, so do not claim everything on the site is correct, although they do try. It is clear they have put a great deal of time and effort into making a substantial site with the honest intention of providing accurate and useful information to teachers. They have won awards for an impressive site. However, in the evolution of humans, they seriously fall down.
The early humans website has several links to good resources. Unfortunately, it has two things that destroy the science educational credibility of the site completely. The first is a link to a presentation teaching Biblical creationism, a subject that has no place in a public school as it is both scientifically invalid and pushes one specific religious view, which is illegal in the United States. Regardless of whether one believes in creationism or not, it is not legal to teach a specific religion in public schools and it is especially not valid to teach that religious view in a science class. The only way to make this legal would be to teach the creationism stories of every other religion equally, without comment as to which one the teacher believed, which would be impossible. Even then, it would have to be in a religious studies class, not a science class. If we are to preserve everyone’s First Amendment rights to freedom of religion, we simply cannot have government-run public schools teach one religious view and we certainly cannot teach that view as a scientifically valid theory. I am hitting this point especially hard because it is a serious point of controversy in the United States, but it should not be. Keeping creationism out of the schools is not an attempt to suppress anyone’s views. It is an attempt to preserve everyone’s right to make their own religious choices without government interference.
That leads me into the second problem, one which is stated boldly right up front. One of the big problems we have in science literacy is that many people do not understand the difference between the colloquial use of the term “theory” and the scientific meaning of the term. To quote the website: “A theory is a guess based on some facts. Remember a theory is not proven. One of the great controversies of our time has been the theory of evolution.” This is massively wrong in two areas.
The term they have defined is NOT a theory. What they defined was SPECULATION. Anyone can come up with an idea, but that does not make it a scientific theory. First, one must have a hypothesis, which is a testable idea, based on observation, that explains a relationship between two or more measurable things. There are two critical parts to this. The observations, so it must be an attempt to explain something we actually see in the real world. Second, that explanation must be testable. If there is no conceivable way to test it, the idea remains in the realm of speculation and can never be taken as a scientific theory, or even a valid hypothesis.
Once one has a series of hypotheses that have been tested by many people, none of whom have been able to disprove the hypotheses, one can formulate a scientific theory. That theory ties the hypotheses together, explaining numerous detailed observations into an explanatory framework that applies broadly. An example of this is the Theory of Gravity. Numerous observations were made showing gravity exists, there is no doubt about that. Many observations showed precisely how it worked and the relationship of different masses to each other, both on earth and in the universe as a whole. However, to make a theory, we needed more than these observations, we needed a way to accurately describe and predict these relationships. Isaac Newton discovered a mathematical equation that could be used to predict the motions of the planets. That equation was then tested many times and found to be valid everywhere, at least at the speeds attained by most things in the universe. Einstein went further with his Theory of Relativity, which extended our understanding of gravity into realms beyond the experience of everyday existence. Even here, these started out as hypotheses, requiring many people to test over and over gain. Not only has no one been able to prove them wrong, but no one has come up with an explanation that better fits the data. Therein lies the key, testing and testing and basing the acceptance of the theory on data, evidence that either supports or disproves the theory. Without that, it is not a theory.
As such, there is no Law of Gravity. We know it exists, it is fact that is undeniable. The Theory of Gravity provides a framework in which gravity works that has been put to the test. In a similar fashion, there is no Law of Evolution. We know it exists, it is a fact that is undeniable. Why? Because the idea that biological life forms change over time is something that cannot be argued against. All one has to do is acknowledge we are not clones of our parents, or look at the diversity of changes brought about by dog and cat breeders, sheep and cow breeders. We see biological change all around us. Evolution is therefore a fact, just like gravity. The Theory of Evolution put forth by Darwin is more properly called the Theory of Natural Selection, which explained this change through the aforementioned natural selection. It has been tested numerous times and shown to work. Is natural selection the only way in which species change? No, but it is a major mechanism. But the point here is that it has been tested and retested. Like all scientific theories, it is not simply a guess based on a few facts. It is permissible to argue about specific mechanisms, but trying to argue whether or not evolution occurs is like arguing whether or not the earth is flat or that we need air to survive.
Time. My day job has kept me extraordinarily busy and away from paleoaerie for a while, thus the lack of new posts here recently, so I thought now would be a good time to discuss temporal issues. Fortunately, things have calmed down a bit and I can get back to working on evolving the website. Speaking of which, it is time I got started.
Time is a subject about which much has been written, especially about our perceptions of time. One of the difficulties some people have with evolution is they don’t see how small changes in a population could lead to the diversity of life we see. They read about small changes in bacteria or they hear about how the average height and longevity of people have changed in the past few decades. They understand that a wide variety of dogs have been created through artificial breeding. But, the dog is still a dog, the bacterium is still a bacterium, people have not changed in their personal experience.
Unfortunately, they do not see how their personal experience misleads them. To them, the world is essentially unchanging. While human culture may change, the mountains do not move and species do not change. It is a common human tendency to assume that whatever is now has been and will always be. However, while we may think of hundreds of years as ancient history and thousands of years as vast swaths of time, they are a tiny speck of how long evolution has been altering life on this planet.
So how does one get people to comprehend the incomprehensibly vast time frames we are talking about? People have tried several ways. One could always simply show them the geologic time scale.
This is the standard geologic time scale used by professionals the world over, put out by the Geological Society of America. But to most people, this doesn’t really help. It is words and numbers and humans are just not that good at really getting a gut level understanding of figures like this. So many people have come up with a variety of metaphors. A common metaphor is compressing the age of the universe into a single year, a la the Cosmic Calendar, as popularized by Carl Sagan and expanded upon nicely by Arif Babul at the University of Victoria.
The idea of condensing all of time into a calendar can be re-envisioned as a clock. If we extend the circular motif to three dimensions, we find another popular image in that of a great spiral of life.
We could also think of time as distance. If, for instance, we decided to get in our car at the Jacksonville, FL airport and drive west and we thought of each mile being 1,000,000 years, we would have to drive to Fairbanks, AL to reach the whole age of the earth. All of human history would be passed by in less than two standard car lengths. An hour into your drive you would pass the asteroid marking the end of the Cretaceous Period and the demise of the non-avian dinosaurs. You would barely be into Tennessee before you passed the Cambrian Explosion over 500,000,000 years ago. By the time you got back to the origins of life, you would be entering the Yukon territories in Canada.
Perhaps you would prefer an interactive in which time was expressed in terms of size.
These are just a few of the ways that time spans can be visualized. Are you looking for something you can bring into a classroom that the students can touch and experiment with? Try having them build a timeline of their own. What is your favorite? Do you have other ideas?