richw9090

The StarChild Skull was a hoax when it first showed up, and it is still a hoax. Or, more accurately, it is simply a child's skull from an archeological site. There is nothing unusual or out of the ordinary about it. It is being hyped, but it is nothing. Rich

To my way of thinking, a theory differs from a hypothesis only in that a theory has been tested by so many different sets of data, generated by different researchers, and always supported, that it becomes folly not to accept it as provisionally true. In addition, a theory is a hypothesis which has productively suggested other additional hypotheses which hve also been tested and found to be supported by the data. As the hypothesis reaches some sort of threshold, it passes into being a theory - which is the highest degree of certainty we can assign to any scientific explanation. Note that it never attains absolute certainty. Absolute Truth (or at least the claim to it) is the domain of religion, not of science. Sometimes a scientific hypothesis is, as soon as it is proposed, recognized to explain such a wide variety of phenomena that it is almost instantly referred to as a theory. The theory of evolution was such an explanation. Its wide applicability, such that everything in biology makes sense when considered in the light of evolution, and the grandeur of its view of life, rendered it a theory almost from the begining. Rich

Looking forward to the two remaining characteristics of hypotheses, Blike. But I'll state what I think characterizes a valid hypothesis in science: It is based on some set of observations (facts) It is an attempt to explain or relate those facts in a systematic way. It is framed in such a way as to be testable - that is, an observation can be imagined which, if obtained, would contradict the hypothesis. It is productive - that is, it suggests further hypotheses (explanations) which can in turn be tested; each one that is confirmed lends further support to the originating hypothesis. Rich

You might try noodling around on www.darwiniana.org

Most of the megafauna became truly extinct at the end of the Ice Age; they were not replaced by new animals, either evolved or immigrants, so today's fauna is a depauperate one. The Mountain Lion, or Puma, was present in Pleistocene times. We are not certain of its immediate ancestor; it may be that the Pliocene Felis lacustris is the ancestor of the modern puma, and may have been the ancestor of the American Cheetah, Miracinonyx, as well. There is still a lot to be discovered about those cats. The sabertoothed cats were an entirely different clade, with no close living relatives. The one Pleistocene fossil cat we do know something about is the American Lion, Panthera atrox, as it used to be named, and Panthera leo atrox as it is currently designated. A close relative of the African Lion and the European Cave Lion, it was an immense animal, and the apex predator of the North American Pleistocene. Two good books, both rather out of date, but written for both a professional and a lay audience, which might help you are: Kurten, Bjorn and Elaine Anderson, 1980, Pleistocene Mammals of North America, Columbia University Press. Kurten, Bjorn, 1968, Pleistocene Mammals of Europe, Aldine Publishing Company Rich

Members of the genus Rattus (the true rats) are very different from members of the genus Neotoma (the packrats). Note that in the time of Linnaeus, almost everything which looked vaguely like a rat was put into the genus Rattus, but it has since been broken into several dozen different genera, on the basis of unique shared derived characters (that is, unique at the subfamily level, shared at the generic level). The common ancestor of Rattus and Neotoma is, by definition, equally far back in the past. Both are in the family Muridae, but are placed in different subfamilies (according to the classification I favor, McKenna and Bell, 1997). The differences between the two genera are may be subtle to the layperson, but they are quite distictive to those who study the critters. Rich