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OBSERVER A: There was this big dinosaur bone, but not too big, which looked gray, like my grandmother's hair, and it was sticking out of the dirt.

OBSERVER B: The object had a linear trend and was 12.5 cm wide with an exposed length of 24.7 cm. It also had millimeter-wide parallel striations running the length of it, a light to medium gray overall color, and a noticeable but slight widening to its distal, rounded end. The host sediment was fine-grained sand mixed with hematitic clay, and the object was protruding at about a 20-degree angle with respect to the horizontal plane of the ground surface.

Observer A showed some promise and laudable enthusiasm, but did a poor job overall of collecting any meaningful data that could be classified or communicated readily to others who did not observe the bone. Observer B used a combination of verbal description and numbers in the data collection, and used a minimum of interpretation (the object was not even identified as a "dinosaur bone" or any other type of bone). Note that the fact of the dinosaur bone's existence does not change with either description. As the preceding example shows, however, the way the bone is described can differ considerably, and if done inadequately can inspire doubt in other potential observers about the factual existence of the bone.

The example also shows some methods of data collection and how data are classified. Data can be collected through either qualitative or quantitative methods. Qualitative methods typically include using oral or written descriptions of the observed phenomena, as well as illustrations. The latter can be diagrams, sketches, or photographs, which are particularly useful for summarizing a large amount of information without added verbosity. Quantitative methods involve the use of measurements and the recording of the numbers associated with them; such measurements may be then described further through statistics and equations. Qualitative and quantitative methods can reinforce one another, such as when a diagram depicts visually what otherwise may be complex mathematical relationships (Fig. 2.2). A cladogram (see Fig. 1.3) is an example of a diagram that combines the results of qualitative and quantitative methods. It is based on observations of anatomical traits, then statistical analyses of the data are used to hypothesize which organisms are the most closely related to one another (Chapter 5).

Once qualitative and quantitative data are carefully collected and communicated to other people, facts become clearer to observers. For example, people have repeatedly observed falling objects and have collected data from these observations, leading them to conclude that gravity is a fact. People have observed repeatedly nuclear reactions and collected data on them, thus they now realize that the effects of nuclear physics are factual. People have observed repeatedly the effects of the development of new species over time and have collected data on these effects, eventually resulting in the knowledge that biological evolution is a fact. Because people have observed repeatedly many bodily remains or traces of dinosaurs and collected much data on them, they also know that the former existence of dinosaurs is a fact. Because the explanations for these observations are equivocal, however, science does not stop with just the gathering of facts. In science, facts and how they occur as real phenomena require interpretations, not just acceptance of their existence.

FIGURE 2.2 Scientific assessment of the skull of Coelophysis baurii, a Late Triassic theropod. (A) Skull of adult Coelophysis, showing qualitative traits (two holes in rear right side of skull, prominent eye socket, sharp teeth); Denver Museum of Science and Nature. (B) Bar graph of skull lengths (n = 15) for Coelophysis bauri, arranged in order of increasing length. Based on data from Cope (1887) and summarized by Colbert (1990).

FIGURE 2.2 Scientific assessment of the skull of Coelophysis baurii, a Late Triassic theropod. (A) Skull of adult Coelophysis, showing qualitative traits (two holes in rear right side of skull, prominent eye socket, sharp teeth); Denver Museum of Science and Nature. (B) Bar graph of skull lengths (n = 15) for Coelophysis bauri, arranged in order of increasing length. Based on data from Cope (1887) and summarized by Colbert (1990).

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