. Biology and man. Biology; Human beings. The differences between the species in one genus are often trivial as against the resemblances between two genera. Species must be "related" in the same sense as cousins are related. The only question is, How far back in the family tree can we find "common ancestors"? Our classifications suggest that if we go back far enough, we may find that ducks and geese are related; or that all birds are related; or that all fishes are related—that is, descended from the same ancestors. If we go back still farther, we may find that all backbone
. Biology and man. Biology; Human beings. The differences between the species in one genus are often trivial as against the resemblances between two genera. Species must be "related" in the same sense as cousins are related. The only question is, How far back in the family tree can we find "common ancestors"? Our classifications suggest that if we go back far enough, we may find that ducks and geese are related; or that all birds are related; or that all fishes are related—that is, descended from the same ancestors. If we go back still farther, we may find that all backboned animals are descended from the same ancestors. There is no reason in advance against assuming that each species has been separately created, or has otherwise arisen independently of all others, as have artificial objects. If that were true, however, we might reasonably expect to find, among the million or more distinguishable forms, at least an occasional species that stood out by itself. It would be like a special commemoration stamp, or some freak "gadget", which differs in its design from all its con- temporaries. However, we find no such unique cases among organic species. Even when we classify the extinct forms, we find that they fit logically into the same general branching arrangement of living forms. Measures of Resemblance If we compare various insects, for example, we shall find that most of the functions are carried on by corresponding organs in the different animals. Thus the locomotive organs in bees, butterflies, and grasshoppers are the legs and wings; and in every case the relative position. © British Museum. World copyright strictly reserved A LIVING ARGUMENT ABOUT FOSSILS In 1939, off the coast of Africa, a living, breathing, scrapping Coelocanth was brought up from the depths in a fishing net. He did not live very long, but long enough to indicate that certain fossils found in old rocks correspond closely to an armored fish that did actually li
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