Voices for Evolution
Geological Society of America (2009) *
Teaching of Evolution
The Geological Society of America strongly supports teaching evolution and the directly related concept of deep time as part of science curricula. GSA opposes teaching creationism alongside evolution in any science classroom. The evolution of life on Earth stands as one of the central concepts of modern science. During the past two centuries, research in geology, paleontology, and biology has produced an increasingly detailed and consistent picture of how life on Earth has evolved.
Science, by definition, is a method of learning about the natural universe by asking questions in such a way that they can be answered empirically and verifiably. If a question cannot be framed so that the answer can be tested, and the test results can be reproduced by others, then it is not science. Creationism, whether in its earlier form as creation "science" or its more recent guise of intelligent design, attempts to explain complicated phenomena of the natural world by invoking a creator or designer. Creationism is not science because it invokes supernatural phenomena that cannot be tested. It therefore has no place in a science curriculum. Because science is limited to explaining natural phenomena through the use of empirical evidence, it cannot provide religious or ultimate explanations. Science teachers should not advocate any religions interpretations of nature and should be nonjudgmental about the personal beliefs of students.
This position statement (1) summarizes GSA's views regarding the teaching of evolution; (2) defines evolution and discusses the physical and biological evidence for evolution; (3) describes the concepts of intelligent design and creation science, and why they are not science; and (4) provides a communications tool for GSA member use.
The rock record provides a treasure trove of fossils, and by the early 1800s, geologists had used physical relationships among rocks to establish the basis for the geologic time scale. They understood that the fossil record shows major changes in life forms over time. In 1859, Darwin's On the Origin of Species showed that these changes can be explained by natural selection operating on random variations in organisms — the process we now know as biological evolution. Since then, we have continued to uncover details of life's history, and biologists have elucidated the genetic and molecular basis for evolution. Evolution is not a static idea but a growing concept added to by scientific observation, testing, and debate. Scientific discoveries in these fields and related disciplines have progressively sharpened our understanding of evolution, which is now well established as a well-tested fact. Evolution is accepted by the scientific community because all available evidence supports the central conclusions of evolutionary science: that life on Earth has evolved and species share common ancestors and genomes.
The discovery of radioactivity in the twentieth century and its use for measuring ages of rocks has made it possible to quantify the age of Earth and to estimate rates of many geologic processes. Many rocks of over a billion years in age can now be dated with great precision. The ages of many rocks have been confirmed by repeated tests in multiple laboratories, often using different isotopic decay schemes. The results are consistent with the processes that uplift the land and cause the erosion and deposition of sediments. Geologists can now identify rocks that record hundreds of millions of years of sedimentation by the slow layer-by-layer accumulation of mud, the rhythmic rise and fall of tides on ancient continental margins, or the slow back-and-forth meandering of rivers in ancient valleys. Organisms that grow only a few millimeters each year have formed reefs hundreds of meters thick. Additionally, techniques that date more recent deposits have been repeatedly and accurately compared to known historical events.
Studies of Earth's history, including the evolution of life on Earth, aid not only in the search for natural resources, but also in the quest to understand how the Earth-life system functions. The geologic record reveals how forms of life have responded to past environmental change, sometimes migrating, sometimes evolving, and sometimes becoming extinct. Understanding evolution has made possible many of the medical advances that save human lives and has furthered agricultural developments that feed the world.
The short-term adaptive evolution demonstrated by the ability of viruses to evolve and adapt to new vaccines, or simply to new environmental conditions, is readily comparable to longer-termed evolution of more advanced species.
From before the time of Darwin, some people have objected to and challenged those findings of science that were considered to conflict with certain traditional religious beliefs about creation. Creation "science" and intelligent design have emerged from religious thought, and because they invoke supernatural phenomena, they cannot frame questions that can be tested scientifically. Therefore, by definition, the notions of creation "science" and intelligent design are not science. The immensity of geologic time and the evolutionary origin of species are concepts that pervade modern geology, biology, and other sciences that support human life. These concepts must therefore be treated as central themes of science courses. Without an adequate knowledge of geologic time and the evolutionary origin of species, students will not understand the processes that shape the natural environment in which they live. As a result, they will lack the understanding that is essential for making wise decisions regarding the environment upon which our survival depends.
Adopted in May 2001; Revised in October 2006; Revised July 2009