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274 pages, Hardcover
First published June 12, 1987
Animals [] deal with phenomenal appearances, not with what things are. They do not distinguish between sense qualities of a thing and what the thing is. Consequently, they are incapable of understanding causes.
the birth rate or the age of first reproduction depends on population density in many large mammals, including white-tailed deer, elk, bison, moose, bighorn sheep, Dall’s sheep, ibex, wildebeest, Himalayan tahr, hippopotamus, lion, grizzly bear, dugong, harp seals, southern elephant seal, spotted porpoise, striped dolphin, blue whale, and sperm whale. Increases in population density alter birth rates in small mammals also. (pp. 125-126)
Between 1800 and 1878, crossbreeding increased the sugar content of sugar beets from 6 percent to 17 percent. But fifty years of subsequent experiments produced no further increases. All experienced breeders recognize the constraints. Luther Burbank: "I know from my experience that I can develop a plum half an inch long or one two and a half inches long, with every possible length in between, but I am willing to admit that it is hopeless to try to get a plum the size of a small pea, or one as big as a grapefruit."