Dinasaurs

Extinction of dinosaurs Evolutionary biologists argue that the group Dinosauria never in truth became extinct, because birds are descended from dinosaurs and hence a part of the Dinosauria lineage. This whitethorn be perfectly true, exclusively it only begs the original question. To take on their objection, we could repeat the question, Why did non-avian dinosaurs become extinct? The problem serene hasnt deceased a manner. 2. There is al moods some uncertainness as to the little timing of any defunctness, and the defunctness of the dinosaurs is sure enough no exception. Workers in Montana bring on disk all all overed dinosaur cadaver, mostly teeth, in the sediments of a stream phone line that is clearly 3rd in age. In places, this stream in reality eroded parts of the terminal cretaceous sediments in the area, and as well contains fossil remain of Early Tertiary mammals. It has been argued that this proves nothing, as the dinosaur remains could bugger off been washed out of in front (i.e. Cretaceous) sediments, and redeposited in the stream channel. The discoverers argue, however, that the remains are unabraded, the teeth are free sharp, and show none of the wear associated with stream redeposition.

The denudation of dinosaur remains above the terminal Cretaceous deposits not in a stream channel would undoubtedly resolve the issue, but so far such remains have not been discovered. punt 3. Percentage of extinction figures are for comparison only, and are free-base on the number of fossil species cognize. In no way does this actually reflect the actual nu mber of species that might have been extant ! before or after any extinction event. The vast majority of the 2 million or so species cognize on Earth today are insects, and over half of those known species are beetles. Insects have been found at least as far back as the carbonaceous Period, yet very few fossil insects are known for any geological period. It can only be phony that insects were vastly more common than the fossil record would indicate. As...If you take to get a full essay, order it on our website: OrderCustomPaper.com

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