. Evolution and animal life; an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animals . 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 p
. Evolution and animal life; an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animals . 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. 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 fertili
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