Get This Book Boundaries of Evolution describes the unlikelihood of evolutionary theory to explain how it is supposed to scale three major biological cliffs. The first cliff is the need for a logical explanation of how random chemical reactions could produce the first living cell from the primordial soup. The second is the problem of explaining how the first single-celled eukaryote evolved from a prokaryote. Mathematical improbabilities of evolutionary theory to scale the first two cliffs, in the time available, are demonstrated.
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What is Science? Is the contemporary theory of evolution an example of good science? What constitutes a good scientific theory? Good scientific theories have the capacity to make sense of a wide range of data that made less sense before the introduction of the theory. In order to be called a scientific theory, it must have been successfully tested and retested many times.
The theory has to live constantly at risk from new data. These are not the only characteristics of a scientific theory, but they probably represent the most important features for practitioners of science. If we hold contemporary evolutionary theory to these standards, how well does it do? These past species lived in populations that underwent gradual transformation so that the individuals in these populations changed their appearance, behaviors, metabolisms, and life histories over long spans of time.
This continual splitting of organismal lineages leads to a nested genealogy of species. This nested genealogy forms a veritable tree of life, whose root represents the first species to arise and whose twigs represent the millions of species living today. If you trace back any pair of twigs from the modern species you will find that their histories merge at some node on the tree where the two species share a common ancestor.
Those individuals with variations better suited to the current environment leave more offspring, thus changing the average appearance of the population over time and making it a better fit to the environment.
This improving fit between organisms and their environment gives the appearance of organisms having been well designed for their milieu. The evidence is actually immense, but I will restrict this discussion to just a few items. First there is the fossil record. If life results from a natural process such as biological evolution, then we should observe a progression of fossil organisms that proceed from relatively simple, single-celled organisms in the oldest rocks to more complex, multicellular organisms in younger rocks.
However, the fossil story gets even better, because scientists can trace evolutionary trends throughout the fossil record. How did this gamble turn out? Bird and anteater embryos show tooth buds that are later absorbed and never erupt.
Baleen whale embryos even develop teeth that are later resorbed. These are relics of their toothed ancestors. Many cave-dwelling animals have rudimentary eyes that cannot see, even though eye development initiates in many of these species, but is later aborted. Such remnants are also found in our genomes. Humans, unlike most mammals, cannot synthesize make our own vitamin C, but we carry the genes for synthesizing vitamin C.
While some of these sequences have been co-opted for particular functions, many of them have no known function. The very presence of these genomic and anatomical flotsam and jetsam only makes sense if evolution has occurred. Hawaii, for example, has no native mammals, reptiles, or amphibians, but a profusion of fruit flies and silversword plants.
These islands were never connected to the continents and arose as a result of volcanic activity and were, at least initially, completely uncolonized. The colonization of these islands occurred by means of occasional introduction of creatures from the mainland that then rapidly speciated on these islands to fill every available ecological niche. Thus, the organisms most closely related to island species come from the closest mainland areas, and often include those creatures most likely to find their way to islands, such as birds and flying insects.
Therefore, he originally listed the warbler finch Certhidea olivacea as a wren and listed the small cactus finch Geospiza scandens as a member of the Icteridae or the family of meadowlarks and orioles. This meeting showed Darwin that the immutable barrier between kinds of species did not exist. A scientific theory also allows scientists to make predictions, and good theories provide accurate predictions.
Can the theory of evolution allow accurate predictions? The answer, once again, is yes. Darwin himself predicted that the earth must be very old for evolution to occur. He did not know the age of the earth, but further research has shown that the earth is 4. Darwin also predicted that since plants on islands were most closely related to certain mainland plant species, the seeds of these plants should be able to withstand immersion in seawater for long periods of time, and again, Darwin was shown to be right.
It has been repeatedly tested for over years since its inception, and it has passed those tests successfully. The theory has been modified in response to new data, but the outlines of the theory have remained largely intact.
It has existed at risk from new data. During the molecular biology revolution that began with the discovery of the structure of DNA by Franklin, Watson and Crick in , the explosion of new data could have shown contemporary evolutionary theory to be wrong.
The ability of a theory to withstand such intense scrutiny is a clear sign it is robust and enduring. As shown, the theory of evolution has predictive power, and it also integrates and makes sense of data from several fields of science, including ecology, paleontology, genetics, historical geology, paleoclimatology, and comparative anatomy and biochemistry.
The highly integrative nature of evolutionary theory makes it a fine theory by any measure. When measured against the standards of a good scientific theory, modern evolutionary biology clearly qualifies as good science. Ongoing debates within evolutionary biology exist about mechanism, rates, and causes, but not over whether evolution occurred.
The future certainly looks bright for this field of science and I cannot imagine a more exciting topic to study. Ratzsch, Del. Kitcher, Philip. Ibid, 42— Hall, Brian K. Burlington, MA: Jones and Bartlett, New York: Oxford University Press, Futuyma, Douglas J.
Sundbury, MA: Sinauer Associates, Valentine, James W. On the Origin of Phyla. Chicago: University of Chicago Press, Carroll, Robert L. Vertebrate Paleontology and Evolution. New York: W. Freeman and Company, Schoch, eds. The Evolution of Perissodactyls. New York: Clarendon Press, Fossil Horses.
Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge, Cambridge University Press, McNamara, Kenneth J. Litchman, E.
Klausmeier, and K. Tattersall, Ian. Darwin, Charles. London: Penguin Books, Hunt, Gene. Clack, Jennifer A. Shubin, and Farish A. Jenkins, Jr. Daeschler, and Farish A. Daeschler, Farish A. Jenkins, and Neil H. Shipman, Pat. New York: Touchstone, Prothero, Donald R. New York: Columbia University Press, Tucker, and Jean-Yves Sire.
Tian, Natasha M. Bejder, L. Lachapelle, M. Avise, John C. Romano, C. Melo, M. Corsini, E. Homes, and P. Coyne, Jerry A. New York: Vintage, Kricher, John.
Biological Evolution: What Makes it Good Science?
Monroe W. Strickberger
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