A month ago, two letters appeared in the Tracy Press criticizing evolution and defending intelligent design.
One asked the rhetorical question, “Where’s the proof?” Another suggested that, “It all boils down to what is it that you believe?”
Philosophy comes down to what you believe. Science boils down to empirically verifiable facts and repeatable experiments.
The theory of evolution incorporates two fundamental assumptions. First, populations of plants and animals have changed slowly over time. The second is that the motor behind change is the tendency of plants and animals to randomly mutate, allowing the process of the survival of the fittest to naturally select the best traits.
The idea of intelligent design is shorn of the biblical references that used to be part of “creationism.” There are various versions of this argument, which include all, or part of the following: Earth is 6,000 to 10,000 years old, all species were created suddenly and simultaneously, and a catastrophic flood caused mass extinctions. There is no scientifically verifiable evidence for any of these conclusions. There is only the “default argument” that says, “Anything in nature that cannot be explained must have supernatural causes.”
Proof of evolution can be found throughout the various sciences. One example is in the fossils uncovered in sedimentary rock. Sedimentary rock usually results from solidified sediment deposited on river, lake and ocean bottoms over millions of years. When such areas are uplifted, due to geologic action, rivers cut through the rock forming gorges. The walls of those canyons form a kind of timeline, with the oldest deposits near the bottom and the more recent sediment layered above. Fossils found in the lower strata are the ancestors of the creatures found above them. We have numerous sequential fossil records of how various species have developed over time. Two weeks ago, the Chinese announced that they had discovered the oldest ancestor yet of Tyrannosaurus rex. It lived 90 million years before the T. rex of “Jurassic Park” fame, was about a third the size of its descendants and had relatively longer arms. The new specimen joins a dozen others on the fossil road to the final version. The fossil record illustrates the process of evolution.
Another source of proof is the presence of vestigial organs in modern creatures, useless leftovers from a previous era. Whales have finger bones in their fins, indicating that they have evolved from land mammals.
Flightless kiwi birds have vestigial functionless wings. Fetal birds develop and lose teeth before they are hatched. Cave dwelling animals and fish have rudimentary sightless eyes and humans have a useless second stomach (the appendix). Studies of the human genome, which tell us about our genetic design, show that at one time humans were able to synthesize (manufacture) vitamin C. Then we discovered fruit! Snakes have an unutilized gene for legs on their genome. All of these examples demonstrate evolution from earlier creatures that had use for such organs and abilities.
Field biologists, like Charles Darwin, have another take on evolution. Darwin concluded that the Galapagos Islands had at one time been a single land mass. As the oceans rose, the peaks became 19 islands.
Landlocked creatures like the iguana and the land tortoise began to change and adapt to slightly different environmental challenges on the various islands. Darwin noted the differences wrought by natural selection.
Field biologists all over the world have corroborated what Darwin observed 170 years ago. Isolated sea islands have a curious similarity. While many have freshwater lakes, none have freshwater fish. Such islands have no mammals other than bats. They tend to have few species of plants that come in many varieties. The logic of evolution easily explains the unique flora and fauna of isolated ocean islands.
Scientists who study microbiology and insects find other examples of natural selection. Diseases like staphylococcus and tuberculosis have become resistant to our best medicines. Many insects have also developed resistance to modern insecticides. Random mutations have allowed them to adapt to these man-made chemical formulations, many of which never existed previously in nature. Microbes and insects are so numerous and multiply so quickly that they are able to evolve in years instead of millennia.
Lake Nicaragua was, at one time, a body of water like San Francisco Bay. A volcanic eruption closed off the connection to the sea. After years of rainfall the new lake gradually turned from saltwater to fresh. While many sea creatures likely perished, some saltwater fish, including sharks, were able to gradually adapt to become freshwater copies of their sea going cousins a few miles away. This is one more “proof” of evolution.
Some say that we should “teach the controversy.” But there is no controversy among practicing scientists.
Supporters of intelligent design have published no empirical studies based on data. There is no controversy about Zeus launching lightening bolts or about Neptune causing hurricanes. These stories belong in an English class until they can meet the same criteria of other theories found in scientific textbooks.
• Mickey McGuire, a retired high school social studies teacher, is among a select group of local residents rotating their columns in the Saturday Tracy Press.
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