On the Genesis of Species (1871)
by St George Jackson Mivart (9780217522984)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III. THE CO-EXISTENCE OF CLOSELY SIMILA.E STRUCTURES OF DIVERSE ORIGIN. Chances against concordant variations.?Examples of discordant ones.? Concordant variations not unlikely on a non-Darwinian evolutionary hypothesis.?Placental and implaccntal mammals.?Birds and reptiles. ? Independent origins of similar sense organs.?The ear.?The eye.? Other coincidences.?Causes besides "Natural Selection" produce concordant variations, in certain geographical regions.?Causes besides "Xatural Selection" produce concordant variations, in certain zoological and botanical groups.?There are homologous parts not genetically related.?Harmony in respect of the organic and inorganic worlds.? Summary and conclusion. The theory of " Natural Selection" supposes that the varied forms and structure of animals and plants have been built up merely by indefinite, fortuitous,1 minute variations in every part and in all directions?those variations only being preserved which are directly or indirectly useful to the individual possessing them, or necessarily correlated with such useful variations. On this theory the chances are almost infinitely great against the independent accidental occurrence and preservation of two similar series of minute variations resultingin the independent development of two closely similar forms. In all cases, no doubt (on this same theory), some adaptation to habit or need would gradually be evolved, but that adaptation would surely be arrived at by different roads. 1 By accidental variations Mr. Darwin does not, of course, mean to imily variations really due to "chance," but to utterly indeterminate antecedents. The organic world supplies us with multitudes of examples of similar functional results being attained by the most diverse means. Thus the body is s...

USD $22.97

   Dispatch: Immediate - In Stock