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Some mathematicians are birds, others are frogs. Birds fly high in the air and survey broad vistas of mathematics out to the far horizon. They delight in concepts that unify our thinking and bring together diverse problems from different parts of the landscape. Frogs live in the mud below and see only the flowers that…
Much as the Drosophila melanogaster fruit fly became a model organism for geneticists, chess became a Drosophila of reasoning. In the late 19th century, Alfred Binet hoped that understanding why certain people excelled at chess would unlock secrets of human thought. Sixty years later, Alan Turing wondered if a…
Michael Dickmann: Here's what the story is. There was this little tadpole and a fish that grew up in a pond, and they were always intensely curious about life outside the pond. And then, eventually, the tadpole grows into a frog and discovers that, because he's an amphibian, he can go out and see what life is like. So…
"But the divine revenge overtook not long after those proud enterprises. For within less than the space of one hundred years, the great Atlantis was utterly lost and destroyed: not by a great earthquake, as your man saith; (for that whole tract is little subject to earthquakes;) but by a particular' deluge or…
This reversibility and this polyvalency endow analogy with a universal field of application. Through it, all the figures in the whole universe can be drawn together. There does exist, however, in this space, furrowed in every direction, one particularly privileged point: it is saturated with analogies (all analogies…
These sprays, dusts, and aerosols are now applied almost universally to farms, gardens, forests, and homes—non-selective chemicals that have the power to kill every insect, the "good" and the "bad," to still the song of birds and the leaping of fish in the streams, to coat the leaves with a deadly film, and to linger…
Now let us examine more closely what we know scientifically about extinction. At the annual Congress of the American Association for the Advancement of Science, as held approximately ten years ago in Philadelphia, two papers were presented in widely-separated parts of the Congress. One was presented in anthropology…
If people ask me about my worldview, I say that I am a naturalist. When most people hear that word, they think of someone who spends a lot of time outdoors watching birds and admiring landscapes—and I suppose that description applies to me. But I think of naturalism as a philosophy rather than a lifestyle. F a…
Let us suppose that we have laid on the table... [a] piece of glass... and let us homologize this glass to a whole order of plants or birds. Let us hit this glass a blow in such a manner as but to crack it up. The sectors circumscribed by cracks following the first blow may here be understood to represent families…
The difference between night and day is dramatic - so dramatic that most species of animal can thrive either in the day or in the night but not both. They usually sleep during their 'off' period. Humans and most birds sleep by night and work at the business of living during the day. Hedgehogs and jaguars and many…
Let us only imagine that birds had studied their own development and that it was they in turn who investigated the structure of the adult mammal and of man. Wouldn't their physiological textbooks teach the following? 'Those four and two-legged animals bear many resemblances to embryos, for their cranial bones are…
Native Missing Plants Land mammals Birds Reptiles Insects and other Amphibians arthropods (e.g., spiders) Freshwater fish [...] Further, when you look at the type of insects and plants native to oceanic islands, they are from groups that are the best colonizers. Most of the insects are small, precisely those that…
Some atavisms can be produced in the laboratory. The most amazing of these is that paragon of rarity, hen’s teeth. In 1980, E. J. Kollar and C. Fisher at the University of Connecticut combined the tissues of two species, grafting the tissue lining the mouth of a chicken embryo on top of tissue from the jaw of a…
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…
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…
Zoologists have traditionally divided the vertebrates into classes: major divisions with names like mammals, birds, reptiles and amphibians. Some zoologists, called 'cladists',* insist that a proper class must consist of animals all of whom share a common ancestor which belonged to that class and which has no…
If sex had no cost, hummingbirds would not exist. Hummingbirds eat nectar, which is produced by flowers to lure pollinating insects and birds. Nectar is a pure gift by the plant of its hard-won sugar to the hummingbird, a gift given only because the hummingbird will then carry pollen to another plant. To have sex with…