. Cyclopedia of farm animals. Domestic animals; Animal products. Anterior Head turned on bocK. Sterno-oOdoinmal pres en tot/on. ripod and feet enooaed l( Fig. 34. Abnormal presenta- tions of foal. [Fii>s. 32-34 adapted from Special Rep., Jjur. Animal Ind., as the appearance of any characters not existing in the ancestors, has been a cornerstone in the development of the most valuable races and breeds of domestic animals. The next step has been the intelligent selection of those variations of peculiar value. Finally, heredity has been relied on to fix and p
. Cyclopedia of farm animals. Domestic animals; Animal products. Anterior Head turned on bocK. Sterno-oOdoinmal pres en tot/on. ripod and feet enooaed l( Fig. 34. Abnormal presenta- tions of foal. [Fii>s. 32-34 adapted from Special Rep., Jjur. Animal Ind., as the appearance of any characters not existing in the ancestors, has been a cornerstone in the development of the most valuable races and breeds of domestic animals. The next step has been the intelligent selection of those variations of peculiar value. Finally, heredity has been relied on to fix and perpetuate desirable variations which have been selected by man. Variation. The organization of all plants and animals is more or less elastic and permits of considerable variation from the established type; thus, all of our domestic animals are constantly tending to depart from the characters of their ancestors. This tendency to vary is retarded or accelerated by many causes. Among these we may mention changed conditions of life. Horses taken to the barren and cold islands of Shetland become grad- ually smaller and hardier, like ponies, and the hair becomes thicker and longer. Long continued exposure to such conditions ultimately results in the production of an animal like the Shetland pony, small in size, extremely hardy, able to withstand the most severe winter climate and to subsist on a minimum of food. Horses taken to the rich low- land pastures of middle Europe gradually become larger and more powerful, like the Percherons. Miles reports a case of an Englishman who intro- duced greyhounds on the high plateaus of Mexico for the purpose of hunting the swift hares. These greyhounds were unable, because of the rarefied air, to run down and capture the hares, but the offspring of these greyhounds could easily run down the hares without fatigue or exhaustion. Heredity is also a cause of variation. The union of two animals with diverse qualities must neces- sarily result in offs
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Keywords: ., bookauthorbaileylh, bookcentury1900, bookdecade1920, bookyear1922
