Word: fossilizing
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Dates: during 1960-1969
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...Cold-Blooded. Assuming that the variation had been similar in prehistoric animals, Ho turned to late Pleistocene epoch (10,000 to 200,000 years ago) fossil remains containing well-preserved collagen. Chemically analyzing the collagen in fossil specimens recovered from Los Angeles' famed La Brea tar pits, he applied his formula and calculated the temperatures of such extinct species as the browsing ground sloth, the dire wolf, the short-faced bear and the saber-toothed...
Without exception, he found that his estimates of body temperatures of the fossil animals were within 3% of the normal temperatures of their modern descendants. The estimated temperature of the browsing ground sloth, for example, was about 96° F., only two degrees above the temperature of its modern contemporary, the two-toed sloth...
...plans to turn his attention to cold-blooded fossil animals, whose temperatures, unlike those of warmblooded creatures, varied with climatic changes. By using his collagen method to take their body temperatures, he believes, he can determine the approximate temperature of the prehistoric climate in which they lived...
When was the earth formed? What are the ancient milestones in man's development? In recent years, scientists have tackled such mysteries by means of radioactive dating. By comparing the amount of radioactive carbon 14 in a fossil with the amount contained in a living counterpart, for example, paleontologists determine when the fossil was part of a functioning organism. Using similar methods, scientists date meaningful objects as old as 3.5 billion years...
...Evidence. Walker's most proven technique is based on the fact that most rocks and minerals contain a small impurity of uranium, which fissions (splits), leaving tiny scars or tracks inside the substance. Until recently, this phenomenon remained unobserved. Walker found that even with an electron microscope the fossil tracks were too tiny-.001 of an inch long and only ten atoms wide-to see in significant numbers...