Philosophy Annotated Bibliography

Only available on StudyMode
  • Download(s) : 227
  • Published : October 4, 2011
Open Document
Text Preview
Wallace, Alfred Russel. (1858). On the tendency of varieties to depart indefinitely from the original type. Zoology, 3, 61-64. The author of this article clearly states his purpose of writing within the first few paragraphs: “to show that (the assumption that varieties occurring in a state of nature are … analogous to or even identical with those of domestic animals, and are governed by the same laws as regards their permanence or further variation) is false, that there is a general principle in nature which will cause many varieties to survive the parent species, and to give rise to successive variations departing further and further from the original type, and which also produces, in domesticated animals, the tendency of varieties to return to the parent form” (62). Wallace continues with this argument (that varieties of species can survive outside of the parent form) with strong points including “that the animal population of a country is generally stationary, being kept down by a periodical deficiency of food and other checks” (62) and that “the comparative abundance or scarcity of the individuals of the several species is entirely due to their organization and resulting habits, which, rendering it more difficult to procure a regular supply of food and to provide for their personal safety in some cases than in others, can only be balanced by a difference in the population which have to exist in a given area” (62-63). He then gives a circumstance in which the variety would replace the original species, where that variety would not be able to return to the original form, which would then be inferior to the existing variety. When he finishes his article, Wallace successfully makes a valid argument: that the progression of classes of varieties further and further from the original species may “be followed out so as to agree with all the phenomena presented by organized beings, their extinction and succession in past ages, and all the extraordinary modifications...
tracking img