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Our bodies teem with other remnants of primate ancestry. We have a vestigial tail: the coccyx, or the triangular end of our spine, that’s made of several fused vertebrae hanging below our pelvis. It’s what remains of the long, useful tail of our ancestors. It still has a function (some useful muscles attach to it)…
Indohyus was not the ancestor of whales, but was almost certainly its cousin. But if we go back four million more years, to fifty-two million years ago, we see what might well be that ancestor. It is a fossil skull from a wolf-sized creature called Pakicetus, which is a bit more whale-like than Indohyus, having…
good candidate is the hippopotamus, which, although closely related to terrestrial mammals, is about as aquatic as a land mammal can get. (There are two species, the pygmy hippo and the “regular” hippo, whose scientific name is, appropriately, Hippopotamus amphibius.) Hippos spend most of their time submerged in…
This is where the prediction comes in. If there were lobe-finned fishes but no terrestrial vertebrates 390 million years ago, and clearly terrestrial vertebrates 360 million years ago, where would you expect to find the transitional forms? Somewhere in between. Following this logic, Shubin predicted that if…
Because reptiles appear in the fossil record before birds, we can guess that the common ancestor of birds and reptiles was an ancient reptile, and would have looked like one. We now know that this common ancestor was a dinosaur. Its overall appearance would give few clues that it was indeed a “missing link”—that one…
It’s important to realize, though, that there’s a real difference in what you expect to see if organisms were consciously designed rather than if they evolved by natural selection. Natural selection is not a master engineer, but a tinkerer. It doesn’t produce the absolute perfection achievable by a designer starting…
By sequencing the DNA of various species and measuring how similar these sequences are, we can reconstruct their evolutionary relationships. This is done by making the entirely reasonable assumption that species having more similar DNA are more closely related—that is, their common ancestors lived more recently. These…
How have all those exquisite adaptations of one part of the organization to another part, and to the conditions of life, and of one distinct organic being, been perfected? We see these beautiful coadaptations most plainly in the woodpecker and missletoe; and only a little less plainly in the humblest parasite which…
A great deal of the universe does not need any explanation. Elephants, for instance. Once molecules have learnt to compete and to create other molecules in their own image, elephants, and things resembling elephants, will in due course be found roaming around the countryside ... Some of the things resembling elephants…
Nature proceeds little by little from things lifeless to animal life in such a way that it is impossible to determine the exact line of demarcation, nor on which side thereof an intermediate form should lie. Thus, next after lifeless things comes the plant, and of plants one will differ from another as to its amount…
If any person thinks the examination of the rest of the animal kingdom an unworthy task, he must hold in like disesteem the study of man. For no one can look at the elements of the human frame—blood, flesh, bones, vessels, and the like—without much repugnance. Moreover, when anyone of the parts or structures, be it…
The dog [in Pavlov's experiments] does not continue to salivate whenever it hears a bell unless sometimes at least an edible offering accompanies the bell. But there are innumerable instances in human life where a single association, never reinforced, results in the establishment of a life-long dynamic system. An…
The mortal enemies of man are not his fellows of another continent or race; they are the aspects of the physical world which limit or challenge his control, the disease germs that attack him and his domesticated plants and animals, and the insects that carry many of these germs as well as working notable direct…
An intelligent patient, private or otherwise, to whom you have taken the trouble to explain the nature of the investigation, makes the best laboratory animal.
Of course there were scientists who thought the evidence favoring DNA was inconclusive and preferred to believe that genes were protein molecules. Francis, however, did not worry about these skeptics. Many were cantankerous fools who unfailingly backed the wrong horses. One could not be a successful scientist without…
Psychologists have tested memory performance in people all over the world and found that those who have completed at least a few years of formal education score higher than those from the same culture and economic status who did not attend school; and the more years completed, the better the performance. Where formal…
Touch plays a very special role in the life of young babies. Because it is so well developed at birth, it provides these brand-new arrivals more detailed access to their fascinating new world than any other sense. Touch is obviously essential to babies' sensory-motor development, but it also has a surprisingly potent…
Initially children use just a few names, mostly for familiar things and people. But when they are still just beginning to talk, many babies will suddenly start naming everything and asking for the names of everything they see. In fact, what'sat? is itself often one of the earliest words. An eighteen-monthold baby will…
It turns out that, just by the nature of the grammar of their languages, Korean- and English-speaking parents talk about the world quite differently. Korean (like Latin or French) uses an elaborate system of different verb endings to convey different meanings. As a consequence, Korean-speaking parents can, and often…
From an evolutionary point of view, it would seem that last-feeding should be one of the more instinctual behaviors, like eating or sleeping or sex. In most mammals, if mothers don't know how to offer their milk or babies don't know how to suckle, the infant dies. If die purpose of reproduction is to pass on genes, it…