The world described by physics is a surprisingly strange world, somewhat distant from our regular experience. Many high school students likely suspect this fact, given the difficulty that they often experience when taking physics courses. However, they are rarely instructed in the explicit difference between the world expressed by their equations and the world that they experience. Many of the concepts used in physics are related to the figures, facts, and equations that are learned in mathematics. The world is recast into a form that looks more like a geometry problem than the world as experienced in day-to-day life. All of this at first seems strange to the budding young physics student. However, after performing a number of experiments, he or she soon sees that these mathematical formulas seem to “work.” That is, these equations really do predict the outcomes of experiments in the real world, not merely in mathematical equations on paper.

Still, it is interesting to notice some examples of how much is overlooked in these kinds of mathematical models. Most obviously, there are few (if any) objects in reality that perfectly match the form and shape of a pure geometric figure. Few physical triangles are exact triangles in the manner of the shapes used in geometric problems. Likewise, motion becomes merely something to be expressed in an equation that has time as a variable. Finally, all of the physical descriptions of light waves tell us about everything except for what it is like to experience color. This last reason is perhaps the most interesting reason of all. No matter how many equations and shapes are used to describe color, none of these will have anything to do with the experience of color itself. To speak of a “rectangular surface” or an “icosahedron-like body” does not tell us anything about colors. Rectangles and icosahedrons can be any color. That is, color does not enter into their definitions at all—a red rectangle is just as much a rectangle as is a green one.

Adapted from “Birds in Retreat” in “Animal Defences—Active Defence” in Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

Among the large running birds are forms, like the African ostrich, in which the absence of powers of flight is largely compensated by the specialization of the legs for the purpose of rapid movement on the ground. For straightforward retreat in open country nothing could be more effective; but another kind of adaptation is required in birds like rails, which are deficient in powers of flight, and yet are able to run through thickly-growing vegetation with such rapidity as to commonly elude their enemies. This is rendered possible by the shape of their bodies, which are relatively narrow and flattened from side to side, so as to easily slip between the stems of grasses, rushes, and similar plants. Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.

Certain birds, unfortunately for themselves, have lost the power of flight without correspondingly increased powers of running, and have paid the penalty of extinction. Such an arrangement, as might be anticipated, was the result of evolution in islands devoid of any predatory ground-animals, and a classic example of it is afforded by the dodo and its allies, birds related to the pigeons. The dodo itself was a large and clumsy-looking species that at one time abounded in the island of Mauritius, which, like oceanic islands generally, possessed no native mammals, while its indigenous reptiles were only represented by lizards. The ubiquitous sailor, however, and the animals (especially swine) which he introduced, brought about the extinction of this helpless bird in less than a century after its first discovery in 1598. Its memory is now only kept green by a few contemporary drawings and descriptions, certain museum remains, and the proverb "as extinct as a dodo.” A similar fate must overtake any organism suddenly exposed to new and unfavorable conditions, if devoid of sufficient plasticity to rapidly accommodate itself to the altered environment.