File:The main currents of zoölogy (1918) (14782566512).jpg

Identifier: maincurrentsofzo00locy (find matches)
Title: The main currents of zoölogy
Year: 1918 (1910s)
Authors: Locy, William A. (William Albert), 1857-1924
Subjects: Zoology -- History
Publisher: New York, H. Holt and company
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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m, but,when the environment varies (or new needs arise),the new conditions of life impress themselves on theplastic organisms and they become altered to betteradapt themselves to these new conditions. Histheory as set forth was comprehensive and includedthe evolution of the human body as well as all other organisms. Adaptation of organisms to environment, in gen-eral and in detail, producing changes of structurethrough use and disuse of organs and the direct in-heritance of the modifications is a simplified state-ment of Lamarcks theory. Until Lamarck was fifty years of age he was abotanist and had secured a lasting reputation in thatfield, but, in 1894, when the Jar din des Plantes wasreorganized he was appointed to a position in Zoologyin charge of the invertebrates. Apparently, it wasthe observations he made in connection with thesenew duties that led to the formulation of his theory.At this time the belief was current that species areunalterable. The dogma of the fixity of species
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FIG. 29.—J. B. LAMARCK (1744-1829)From Thorntons British Plants, 1805 THEORIES OF EVOLUTION 147 prevailed. Linnaeus had announced himself in favorof the idea, and, so generally was his authority recog-nized, that scarcely anyone thought of bringing itinto question. But Lamarck saw that species varyin a state of nature to such an extent that they passbeyond the limits that can, in reason, be assigned tospecies. Lamarcks theory, although so definite, did notfind a foothold during his lifetime and the fifty yearsbetween 1809, when his book was published, and1859, when Darwins Origin of Species appeared, wascharacterized by the temporary disappearance ofthe theory of organic evolution. His ideas wereridiculed by Cuvier and were practically laughed outof court. Charles Danvin also paid little heed toLamarck as a predecessor. But, it is a significantcircumstance that, nearly a century after beingpromulgated, Lamarcks principle of use-inheritanceand the beginning of variations should have

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