As I’ve posted about before, I am taking college courses online in my “free” time. As part of my current Biology course, I am participating in an online seminar hosted by the American Museum of Natural History. The Seminar is Evolution.
Every week participants are given various reading assignments and other resources to use. We are then expected to participate in a group discussion based on that week’s question. Here is this week’s question:
Theodosius Dobzhansky, the famous evolutionary geneticist, wrote in 1973 that “nothing in biology makes sense except in the light of evolution.” Why is evolution the fundamental concept that underlies all life science? If evolution is “true”â€”if life really has evolvedâ€”what would we expect to observe as a consequence? How could this lead to testable hypotheses?
See my answer on the jump …
When I talk with others about what evolution is and why is it important, I like to use a puzzle analogy. You have before you a table covered with jigsaw puzzle pieces, but you have no finished picture to look at and guide you. You simply have to work your way through it as best as you can. You need to look at the pieces and develop a few hypothesizes about how things fit together. Perhaps sorting out all the pieces with straight edges would be a good start. Then see if pieces with similar colors and patterns might match one another. Once a blob of the actual overall picture emerges, you can then see that the finished puzzle might be about furry animals near water of some type, maybe puppies or kittens checking out a pool. That can then guide the completion of the puzzle. Eventually, the final product emerges. It turns out it was a picture of a cute baby seal on the beach. But the puzzle has some holes in it where some pieces are missing. Some holes are small and some are huge. There are even a few pieces lying around that donâ€™t seem to have a home just yet. You still have yet to figure out where they go and what they represent in the overall picture.
Understanding why evolution is the fundamental concept that underlies all life science first necessitates an understanding of what the theory is meant to do. Evolution is not some odd idea pulled out of thin air. Evolution is not a dogmatic set of arbitrary rules that one must adhere to. Evolution takes a collection of known facts and observations and pieces it all together in a way that makes the most sense. Itâ€™s the blueprints of your house, or the outline of your college term paper. Without the blueprints or outline, you have a stack of wood or an incoherent rambling.
For the sake of argument, letâ€™s say that the theory of evolution isnâ€™t the best explanation for the facts we know. Fine. Take away evolutionâ€™s explanatory power and weâ€™re left with a jumble of bones, a massive pile of genetic research, apparent similarities in divergent species, changing disease-causing viruses, etc. Fine again. Weâ€™re back to a tabletop covered in puzzle pieces. What now? Taking away the theory doesnâ€™t erase the facts. One still has to figure out how it all properly fits together without sweeping some of the pieces you donâ€™t like off the table and taking a hammer to others you desperately want to fit together.
But evolution is presently the single best explanation for what we see and how it all fits together. As I said earlier, evolution is not dogmatism. Itâ€™s an idea thatâ€™s been tested again and again. If it failed the tests, it would have been discarded decades ago. Itâ€™s a waste of time and effort to prop up something that has no value to research. Robert T. Pennock put it this way in his essay in Evolutionary Science and Society: Educating a New Generation:
â€œThe ultimate test in science is pragmatic. That a claim is put in scientific-sounding language does not make it scientific; for something to be recognized as a scientific fact, it cannot just talk the talk; it must walk the walk. That is to say, it has to make an empirical difference. Put another way, there is good reason to conclude that we have got our hands on a real fact when using it works.â€
Pennock then goes on to list ways that evolution is useful: tracking diseases through the tree of life, prescribing medicines that bacteria are less likely to evolve resistance to, and learning more about our own bodiesâ€™ natural defenses. Evolution connects us humans to the vast array of life on this planet, past and present.
But how is evolution tested? Dr. Niles Eldredge, in his essay Evolution: A Paleontologist’s Perspective, outlines two such general tests:
1) If life has evolved, there should be nested patterns of resemblance linking up all life.
2) If life has evolved, we should observe a general sequence of primitive to more advanced forms in the history of life.
As Dr. Eldredge then goes on to show, evolution passes these tests without problem.
Furthermore, Pennock gives us some scope of what evolution is encompassing: â€œEvolution is the linking explanatory framework between internal (genetic) and external (environmental) factors and between efficient (historical) and functional (teleological) analyses of phenomena.â€
The bottom line is that the overall theory of evolution is an explanation that best fits the data. If it did a lousy job of piecing everything together, it would have been tossed on the garbage heap and some better scientific theory would be in its place right now. Not only does it do a great job of explaining, but it also has a myriad of useful, real-life applications.
That was my contribution to the group discussion. I welcome your input in the comments here, and I will share any interesting insight from other AMNH Seminar participants in the comments, too. Feel free to correct anything you think I got wrong, or add any points that would help better answer the original question.
Also, I find it funny that this week’s question relates directly to what one commenter here at FCS is has been complaining about lately: He doesn’t think evolution is the fundamental concept that underlies all life science.