Teaching About Evolution and the Nature of Science (1998) / Chapter Skim
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Chapter 3: Evolution and the Nature of Science
Chapter 3: Evolution and the Nature of Science
Pages 27-46
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From page 27... ...
For our own phylum, the Chordata, this move away from the Id the Science nurturing sea led to the appearance of amphibians, reptiles, birds, and mammals—the latter including, of course, our own species, Homo sapiens. This chapter looks at how science works in the context of our overall understanding of how biological evolution occurred.
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From page 28... ...
led the way to a new understanding of the relationship between the earth and the sun and initiated an age of scientific progress that continues today. Illustration from the 18th century depicts the Ptolemaic system in the upper left corner and the Copernican system in other corners and i)
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From page 29... ...
Careful observations of the movements of the stars and planets greatly complicated the hypotheses used to account for those movements. This growing complexity stimulated some of the leading astronomers of the 16th and 17th centuries, including Copernicus, Kepler, and Galileo, to make even more precise observations of the movements of the heavenly bodies.
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From page 30... ...
Science Requires Careful Description What are the scientific methods that have led to our current understanding of the history of life over vast eons of time? They begin with careful descriptions of the material being studied.
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It is now believed that the number of different species of plants and animals in the world may be ten miTlion, or even more. The scientific methods used in classifying organisms have been greatly improved over time.
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From page 32... ...
S clence as Explanation In the quest for understanding, science involves a great deal of careful observation that eventually produces an elaborate written description of the natural world.
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From page 33... ...
Storms produce powerful waves that erode cliffs at the seashore. These phenomena have the common feature of moving solid materials, and the subsequent settling out of these materials makes possible the formation of a special form of rock that contains a record of the earth's past.
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From page 34... ...
Because these methods are based on the known rates of radioactive decay, they provide valuable measures of absolute time. The scientific study of fossils is called paleontology, and the methods used for their identification and classification are similar to those used for living species.
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From page 35... ...
In South America, the only continent where living armadillos were found, Darwin discovered fossil evidence for the prior Dating the Earth One of the greatest scientific triumphs of the last two centuries has been the discovery of the vast expanse of geologic time. Early methods of calculating the age of the earth relied on measures of the rate of sedimentation or the cooling of the earth from an initially molten state.
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From page 36... ...
While the estimated times of various evolutionary events continue to change as new fossils are discovered and dating methods are refined, the overall sequence demonstrates both the scope and grandeur of evolutionary change. A- Formation of earth and moon -- Likely origin of life I - Oldest known rocks and fossils Elm BE1 - 1
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From page 37... ...
Pigeon breeders, for example, had observed wide differences in colors, beaks, necks, feet, and tails of the offspring from a single mating pair. They routinely enhanced their stocks for desired traits—for example, selectively breeding those animals that shared a particular type of beak.
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From page 38... ...
By floating snails on salt-water for prolonged periods, Darwin convinced himself that, on rare occasions in the past, snails might in fact have "floated in chunks of ([rifted timber across moderately wide arms of the sea." This example shows how a hypothesis can ([rive a scientist to do experiments that would otherwise not be done. Prior to Darwin, the existence of lancl snails and bats, but not typical terrestrial mammals, on the oceanic islands was simply note(1 an(1 catalogued as a fact.
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From page 39... ...
For example, since DaIwin's time, paleontologists have discovered many ancient organisms that connect major groups such as Archaeopter~x between ancient reptiles and birds, and Ichthyostega between ancient fish and amphibians. By now, so much evidence has been found that supports the fundamental idea of biological evolution that its occurrence is no longer questioned in science.
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From page 40... ...
The hypothesis of continental drift was equivalent to the hypothesis of evolution in the decades before Darwin, when evolution lacked the idea of variation followed by natural selection as an explanatory mechanism. The argument essentially lay dormant until improved technologies allowed scientists to gather previously unobtainable data.
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From page 41... ...
On a time scale of millions of years, these plates shift about on the planet's surface, changing the relative positions of the continents. The plate tectonic model provides explanations that are widely accepted for the evolution of crustal features such as folded mountain chains, zones of active volcanoes and earthquakes, and deep ocean floor trenches.
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From page 42... ...
These fundamental characteristics of science have demonstrated remarkable power in allowing us to describe the natural world accurately and to identify the underlying causes of natural phenomena. This understanding has great practical value, in part because it allows us to better predict future events that rely on natural processes.
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From page 43... ...
When early humans tried to give explanations for natural phenomena, particularly for disasters, invariably they invoked supernatural beings and forces, and even today divine revelation is as legitimate a source of truth for many pious Christians as is science. Virtually all scientists known to me personally have religion in the best sense of this word, but scientists do not invoke supernatural causation or divine revelation.
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