Page:The New International Encyclopædia 1st ed. v. 20.djvu/933

ZOOLOGY. 795 ZOQUE. inilcpondcntly by others, as Cope, Hyatt, Jack- son, Kiiiier, etc., proving that the Lamarckian factors of cliange of environment, use and disuse, even if we tlirow out use-inlieritance as applied to mutilations, etc., are the priniar.v ageneies in luodifyinj; organisms and in brinfiing about not ouly varieties and species, but also families, orders, classes, and even phyla. Natural selection also has its foundation in the struggle for existence and competition. And here it is interesting to observe that Darwin and Wallace, who independently thouglit out the selection idea, both acknowledge their indebt- edness to Malthus's "Essay on Population" (1798) for the idea which dominates their theory. It is not, perhaps, generally known that JIalthus on his part freely acknowledged in the open- ing pages of his essay his indebtedness to Benja- min Franklin for the motif of his work. In 1755, in his Obfcrvationfi Concerning the Increase of ilunkind and the PeopUntj of Countries, Franklin enunciated the principle of struggle for existence, and the evil effects of overcrowding if any single species were allowed to multiply unchecked by competition with other forms. "There is, in short," he says, "no bound to the prolific nature of plants and animals, but what is made by their crowding and interfering with each other's means of subsistence. Were the face of the earth vacant of other plants, it might be gradually sowed and overspread with one kind only, as, for instance, with fennel, and were it empty of other inhabitants, it might in a few ages be replenished from one nation only, as, for instance, with Englishmen." (Sparks's edition of the Works of B. Franklin, vol. ii., p. 319.) The theory of descent has aroused atten- tion and given a decided impulse to the study of bionomics, ethology, or the habits and instincts of animals and their relations to the world around them. The pioneers in this captivating phase of biology were Huber, Reaumur, Reimarus, Sie- bold, and Leuekart, and. to come down to later times, Lubbock, Romanes. W yman. Plateau, Forel, Fabre, iloggridge. Cook. G. ". and E. (}. Peckham, Loeb. Weismann, and Wheeler deserve special mention. One great ditl'erence between plants and ani- mals is that the latter move from one place to an()ther; and how animals orientate themselves and the means or sense-organs by which they move in reference to surrounding objects or organisms, find their food, or their mates, has engaged and is now engaging much attention. Here might be cited recent work on the otocysts of the inverte- brates, and the views now lield as to the origin of the vertebrate ear and the lateral sense-organs of fishes and salamanders from organs of orienta- tion in the worms. The mechanics of locomotion worked out by the older anatomists and physio- logists have, by the ingenious inventions and use of photography, been greatly extended by Marey. Finally, our knowledge of the physiology of nerves and ganglia, as well as of the brain, of the more specialized animals and of man, has had its bearings on comparative psychology, and under the influence of the experiments of Loeb, Bethe, and others we are coming into a position to dis- criminate between simple plwsiological or reflex acts and instinctive acts, and to compare them Vol. XX.— 61. with the acts of human reason. And here again we see that plants and animals approximate, in that the reflex acts of the lowest animals, those without nerves or ganglia, are akin to the re- stricted movements of certain plants. As is well known, Darwin's theory of selection is ba.sed on his assumption of the universal ten- dency to variation, a plicnomenon he did not at the outset attempt to explain. The Lamarckian factors of change of the conditions of life, of climate, and .soil, are what we rely on to account for variations, as indicated by Darwin later in life, strongly insisted on by Herl)ert Spencer, by Sachs, Semper, Kerner, and their successors. Within the past few years the study of varia- tion, from a general as well as statistical point of view, has already reached very considerable proportions. According to the results obtained by J. A. Allen, Wagner, Wallace, and others, a very large proportion of existing varieties and species are local, geographical, or climatic forms, due to migration, geographical changes, and re- sulting isolation. Bateson has collected in a thick volume all the known cases of discontinu- ous variations, and many species, as claimed by Gallon, also by De Vries, owe their origin to sports or aberrations. Statistical variations, consisting of the minute measurements of multi- tudes of individuals, studies initiated by Gould, Baird, Allen, Weldon, Pearson. Davenport, and otliers, all tend to show that the variations are due to local differences in climate, soil, tem])cra- ture. the nature of the medium, etc., with the result that tlie doctrine of the essential unfixity of species, the high degree of unstable equilib- • riimi of organisms, is a fundamental fact with which the biologist has more and more to deal. Consult: Geschichte dcr Zoologie (Munich, 1872) ; Packard, in Standard Nat-ural History (1885): Packer and Haswell. Zoologi/ (Xew York. 1S97). ZOOPHYTE (.Gk. fv6(ii;Toi', zoophiiton. zo- ophyte, animal-plant, from ^i^ov. zoon, animal + (t>VTbv, phyton, plant). A term employed by Cu- vier to designate the lowest primary division of the animal kingdom, which includes many ani- mal organisms that are fixed to a definite spot or rock, shell, etc., and have the form of plants. The group was a very artificial one, and the term gradually fell into disuse and is no longer employed except as a semi-popular term to de- scribe hydroids. corals, sea-anemones, and some other forms, which superficially bear some resem- blance to flowers. ZOOSPORE (from Gk. fvov, zoon, animal + (TTTopd, spora, seed), or 'swarm-spore.' The ciliated or motile asexual spores common among the alga^ and aquatic fungi. See Spore. ZOQUE, so'ka. A Jlexican tribe of low culture occupying portions of eastern Tabasco and the adjacent districts of Chiapas and Oaxaca, and, together with the neighboring Jlixe and one or two other tribes, constituting the Zoquean lin- guistic stock. They were formerly a numerous and formidable people, brave, savage, and ad- dicted to cannibalism, but are now reduced to less than 3000, described as agricultural and in- dustrious, but stupid, coarse featured, and great drimkards. Like other tribes of Mexico, they retain many of their ancient beliefs and customs under a thin veil of civilization. Consult: San-