File:Biology in America ((c1922)) (20194102730).jpg

Title: Biology in America
Identifier: biologyinamerica00youn (find matches)
Year: (c1922) ((c10s)
Authors: Young, R. T. (Robert Thompson), b. 1874
Subjects: Biology
Publisher: Boston, R. G. Badger
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
The Story of the Roclcs 137 mens, which are therefore on exactly the same scale. The single dinosanrian tooth p-ceatly exceeds not only the tooth of the nianniial, but the (•ination conjure.-; it up. "2 As to the cause of mammalian development we can again only conjecture. Lull has suggested that increasing dryness of climate and corresponding desert conditions, necessitar- ing speed on the part of animals in search of food and water, or in flight from their enemies, coupled with the extensive glaciation in the Southern hemisphere in late Palaeozoic times,
Text Appearing After Image:
Tooth of a Dinosaur Compared with the Jaw of a Coxtempuraky Mammal From Lull's Organic Evolution. Courtesji of Professor Lull mid tlit' Miicmilhiii ComiJiniii. which glaciation would mean increasing cold and the nred of a furry covering, were the inciting causes. But apart from the fact that this explanation implies, if it does not state, an acceptance of Lamarck's doctrine, which at the present time is in the discard with most zoologists, is the further fact that the succeeding or Mesozoic era was one which witnessed the remarkable development of reptiles, which are distinctly types not adapted to aridity and cold- ness of climate. Perhaps the best we can do after all, when, as so frequently happens in pliilosophy and science, we find ^Lull, "Evolution of the Earth," pp. 133-134. By permission of the Yale University Press.

Note About Images