interrelationship of species, there is a tree on Mauritius whose seeds will not germinate unless the fruit has first passed through the digestive track of the dodo. The dodo's digestive juices scarify the seed and when it is finally deposited (with fertilizer) it sprouts. All the tree of this type on Mauritius are now at least 300 years old. No new ones will sprout and, eventually, the tree ...
years old, so it was swimming the ocean 10 million years after whales first evolved. And though 10 million years had passed, it still had hind legs. Not much to be sure, but the bones are there and cannot be mistaken. If they were stretched out in a straight line, they would be two feet long. They include a femur (the bone of the upper leg), a tibia and fibula (the two bones of the lower leg), ...
the discovery implied that at least some cancers were virus diseases.Other scientists were skeptical but as the years passed there were additional cases of the production of cancer in animals by injection, and in 1966, 55 years after the discovery, Rous (then 87 years old and still working) received a Nobel Prize for it.It was known that viruses contained nucleic acid. So do all living cells. ...
Earth.Can we be sure? After all, that rare fungus does form isovaline. Perhaps 65million years ago, some animals that passed into extinction happened to make copious quantities of these amino acids that are rare now, but weren't rare then.No, we can be sure that didn't happen. Amino acids, like many other substances important to life, have asymmetric molecules and can exist in either of two ...
and the news was given to Niels Bohr, who was on his way to the United States to attend a scientific conference. He passed it on to American physicists, who instantly repeated the experiments and confirmed the existence of nuclear fission. This time the wild and dramatic notion was true.Well, now which is it to be for cold fusion? After all, if cold fusion really exists and can be exploited, ...
actually passed Earth at a distance of only 30 miles above the surface of southern Montana and whizzed on. It had passed through our stratosphere.Some astronomers think there may be at least a hundred objects that are half a mile or more across and that have orbits that send them skimming by Earth. And there may be thousands that are a few dozen feet across. Obviously the chance that some ...
the newly created molecules on to daughter cells. Such sets also exist in sperm and egg cells, so that they can be passed on from parents to children. Every living species has its own set and there are also tiny differences in the sets of different individuals of the same species.The importance of DNA was first recognized in 1944, and scientists labored to find out how these molecules could ...
years ago and produced a disaster that destroyed much of life on Earth, including all the dinosaurs.As the years have passed, evidence in favor of such a strike has accumulated, and while there are still questions and disagreements, most scientists seem to have accepted this explanation of the dinosaurs' demise.Naturally, the question arose as to why such a strike, formidable though it may ...
their emergence had not been missed for one reason or other, the conclusion we must come to is that they had actually passed so deeply into the sun's atmosphere that their orbits degenerated and they spiralled into the sun itself.Presumably, this happens now and then, and even more frequently for still smaller objects such as those we call meteorites if they struck the Earth. Nevertheless, ...
circles over about a one-year period. The motion was too small for anyone to detect at the time, but as the decades passed, telescope and other instruments became more precise and delicate.Finally, in 1892, an American astronomer, Seth C. Chandler, was able to study the stars so accurately that he could detect very tiny shifts in their position that could best be explained by the shifting of ...