The Nature of Science
Students are often attracted to the vast body of knowledge our culture associates with science. Science teachers feel pressure to deliver the content of their curriculum within a time frame that is often inadequate. Preoccupations with science content may actually catalyze scientific illiteracy. Rather than being taught the ways that science arrives at its conclusions, students are often taught the conclusions at which science arrives. A deep and meaningful understanding of science does not come from learning its content alone, rather, one needs an awareness of how scientific knowledge is gathered and accepted. It is our hope that the following articles will help students and teachers explore how science works.
In 1796, William Smith (1769-1839), an English geologist, found he could identify individual layers of rock by the fossils unique to each layer (Winchester, 2002, pp 116-117). Smith was able to map out the succession of fossils found in different rock formations. His geologic maps showed that life forms appear and disappear through time.
Georges Cuvier (1769-1832), the great French anatomist set the standard for the new science of paleontology. In his historic lecture of 1796, Cuvier established extinction as a fact using evidence from fossil mammoths. Cuvier was also the first to note mass extinctions at what we now define as the end of the Paleozoic and Mesozoic Eras. George Cuvier and Alexandre Brongniart (1770-1847), a French naturalist and geologist mapped the Paris Basin. In reconstructing the changing sea levels of the Atlantic Ocean Brongnairt and Cuvier showed that fossils had been laid down during alternating fresh and salt-water conditions thus establishing the fact that there existed a succession of fossils in different formations representing different environments.
A History of Life on Earth
Cuvier noticed that the more ancient a fossil the less it resembled present day organisms. In ordering fossils chronologically Cuvier, like Smith, was constructing a history of life on Earth using geologic strata. Thus began the science of
biostratigraphy. Cuvier was opposed to early theories of evolution and viewed faunal succession as evidence for a cycle of creation and extinction known as the Theory of Catastrophism. Cuvier's vital contributions to our understanding of geologic time are ironic. As Michael Benton (2001), an English paleontologist, points out Cuvier was unable to "...make two vital connections: between extinction and evolution, and between geological change and time (p. 99)." Stephen J. Gould (1941-2002), an American evolutionary biologist, believed the geologic time table to be one of the greatest contributions to human understanding (2001).
"The establishment of a time scale, and the working out of a consistent and worldwide sequence of changes in fossils through the stratigraphic record, represents the major triumph of the developing science of geology during the first half of the nineteenth centruy....By 1850, geology had developed a coherent global chronology based on life's history. This discovery and construction of history itself must rank as the greatest contribution ever made--indeed, I would argue, ever makable--by geology to human understanding. (p.15)."
Changing Patterns of Life
Paleontologists continue to discover evolutionary patterns of life on Earth by correlating new fossil discoveries to the geologic time table. Students can discover changing life patterns though time as they explore the fossil record in our museum.
The dropdown menus above can be used to visit each time period. In each time period you will find an introduction along with fossil galleries. Introductions identify major life forms that existed during the geologic period. Fossil galleries provide visual examples of organisms from specific fossil deposits. Use our museum for time travel. Trace your journey keeping track of the appearance and persistence of life forms through deep time.
Topics related to geologic time and permineralized plant material can be found on the sidebar menu. The information and exercises provided in the sidebar menu can deepen your understanding of geologic time, how fossils form, and the history of life on Earth, a revelation from the fossil record.
Benton, M. (2001). Four Feet on the Ground. In Gould, S. [Ed]. The Book of Life: An Illustrated History of the Evolution of Life on Earth (pp. 79-126). New York: W.W. Norton & Company, Inc.
Gould, S. (2001). Reconstructing (and Deconstructing) the Past. In Gould, S. [Ed]. The Book of Life: An Illustrated History of the Evolution of Life on Earth (pp. 6-21). New York: W.W. Norton & Company, Inc.
Winchester, S. (2002). The Map That Changed the World: William Smith and the Birth of Modern Geology. New York: Harper Collins Publishers.