Identifier: evolutionanimall00jord (find matches)
Title: Evolution and animal life; an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animals
Year: 1907 (1900s)
Authors: Jordan, David Starr, 1851-1931 Kellogg, Vernon L. (Vernon Lyman), 1867-1937
Subjects: Evolution
Publisher: New York, D. Appleton and Company
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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:
that where a certain char-acter in the mother is represented in the father by one of oppo-site condition, as where the mother is very short, the father verytall, the mother a brunette, the father light-haired, a given childcan inherit the character in only one condition. That is, in allcases of biparental reproduction, and they compose the majorityof cases in both animal and plant kingdoms, the inherited char-acters cannot be all those possessed by both parents, but mustbe either those of one or the other, or a mosaic of them, or ablend or fusion of them. And this introduces us to that phase HEREDITY 183 of the study of the results of heredity which to-day is being mostinvestigated, the determination of the laws of inheritanceof characteristics. The similarity or dissimilarity of the two mating parents is amatter of much importance in regard to the results of inherit-ance. To produce a fertile mating the two parents have atleast to be nearly allied. We are accustomed to take this for
Text Appearing After Image:
FIG. 115.—Romulus, the striped colt of a horse mother and zebra father. (After Ewart.) granted, but the actual degree of phyletic relationship necessaryin fertile mating is a point of much biologic interest. In mostcases both parents must belong to the same species or kind, butamong animals and plants there have been noted exceptionsto this rule, these exceptions constituting the facts of hybridi-zation. Hybridism is practically limited to mating of differentspecies of the same genera. Only in a few recorded cases haveorganisms of different genera mated in nature with the produc-tion of offspring. In zoological gardens and menageries the 184 ETOLUTION AND ANIMAL LIFE race feeling of the confined animals seems to break down, andunusual cases of hybridism are occasionally noted. Also men-tion must be made of the artificial induction of the fertilizationof sea-urchin eggs by the sperm cells of starfishes (animals notonly of different genera but of different families), and a few othersi

Note About Images