Evolution of Sea Turtle Migrations

Each year around Christmas time, green turtles (Chelonia mydas) leave their shallow feeding grounds along the coast of Brazil and embark upon a 2000 km journey to their nesting grounds, the beaches of Ascension Island, in the mid-Atlantic. The journey takes a little more than 2 months in both directions, and is a miracle of navigation. Biologists have long wondered how the turtles manage the feat, and also why they bother to do it at all. Fifteen years ago two researchers, Archie Carr and Pa...

 Reasons the Dinosaurs Went Extinct

Why Become Extinct? Authors with varying competence have suggested that dinosaurs disappeared because the climate deteriorated (became suddenly or slowly too hot or cold or dry or wet), or that the diet did (with too much food or not enough of such substances as fern oil; from poisons in water or plants or ingested minerals; by bankruptcy of calcium or other necessary elements). Other writers have put the blame on disease, parasites, wars, anatomical or metabolic disorders (slipped vertebral ...

 The Impossibility of Continental Drift

Even more difficult to explain, than the breaking-up of a single mass into fragments, and the drifting apart of these blocks to form the foundations of the present-day continents, is the explanation of the original production of the single mass, or PANGAEA, by the concentration of the former holosphere of granitic sial into a hemisphere of compressed and crushed gneisses and schists. Creep and the effects of compression, due to shrinking or other causes, have been appealed to but this is hard...

 Many Hypotheses Become Theories

The distinction between the two dictionary meanings of 'theory' is not an unbridgeable chasm, as many historical examples show. In the history of science, theorums often start off as 'mere' hypotheses. Like the theory of continental drift, an idea may even begin its career mired in ridicule, before progressing by painful steps to the status of a theorum or undisputed fact. This is not a philosophically difficult point. The fact that some widely held past beliefs have been conclusively proved ...