OCR Text |
Show 10 INTRODUCTION. on t1· tu t'1 0n and c11'm"n" te · Still more surpnsmg . was th. e fac.t that mo t of the inhabitant of each separate 1 land m tlns mall ur ·h ip ]acro w r pecifically diffi rent, ~hou~h :no t clo ely relat d to each thcr. The archipelago, w1th 1ts wnume~·a~le cratez ~and bare . tr am of laYa, appeared to be of recent ongm · and thu I fancied my ~ lf brought near to the Yery act of cr ation. I oft n a ked my ·elf how the e many peculiar animals and plant had been prodnced: the . imple t an wer seemed to b that the inhabitant of the - \'eral 1 land bad de c nd d from ea h other, undergoina modifictltion in the cour e of their de cent; and that all the inhabitant of the archipelago bad de -cellded from tho e of the n ar t Janel, namely Am rica, whence colond v;·ould naturally haYc been deriYed. But it long remained to me an inexplicable problem how the nece ·ary d •gree of modification conlJ. baY becu e.ffi ·ted, and it would have thu r 'mained for e>er had I n t tucliecl dome tic production , and tbu acquired a ju t idea of the power of Selection. A oon a I had fully r aliz d thi id a, I aw, on r eading l\Ialthu on Population that X at ural ele tion wa the inevitable r ult of the rapid incr n-e of all orcrauic beincr ; for I wa' prepared to appreciat the "truggle for xdence by having long tudied the habit~ of animal . fore •i-iting the GalapnO'o I had collected many animals whil t traY lliug from north to outh on both ide of .. .\.merica, and Y rywb r , und r condition· of l ife a· different a it is p s·ible to c nceive, _\mcrican form- were met with-~·pecic rep Iarin()' ,pec ie- of th ame peculiar genera. Tlm ~ it \Ya when th' on.lillera wer a- 'eml Ll or the thick tropical forest penetrnt d, or the fr sh wat r::. of America earched. ub·equently I Yi ·ited oth r couutrie-. \rhit:h in all the condition of life were incomparably m r like to part of outh America, than the different part- of that contin nt '" re to ach other; yet in the' ountrie , a in Australia or outhern Africa, the tru.Yeller cnnuot fail to be ·truck with the entire tlilferen e of their production . AO'ain the refle ·tiou wa- forced on me that community f de nt from th' early inhabitant" or coloni -t· of outh America would alone explain the wide preYalence of Americ~m type of tructur throuO']wut that imm u ·e ar a. To xhume with one' own hand- the bones of extinct and NATURAL SELECTION. 11 gigantic quadrupeds brings the whole question of the succession of species vividly before one's mind; and I had found in South America great pieces of t esselated armour exactly like, but on a magnificent scale, that covering the pigmy armadillo ; I had found great teeth like those of the living sloth, and bones like those of the cavy. An analogous succession of allied forms had been previou ly observed in Australia. Here then we see the prevalence, as if by descent, in time as in space, of the same types in the same areas ; and in neither case docs the similarity of the conditions by any means seem sufficient to account for the similarity of the forms of life. It is notorious that the fos il remains of closely consecutive formations are closely allied in structure, and we can at once understand the fact if they are likewise closely allied by descent. The succession of the many distinct species of the same genus throughout the long series of geological formations seems to have been unbroken or continuous. New species come in gradually one by one. Ancient and extinct forms of life often show combined or intermediate characters, like the words of a dead language with respect to its several o.ITI:lhoots or living tongues. All these and other such facts seemed to me to point to descent with modification as the method of production of new groups of species. The innumerable past and present inhabitants of the world are connected together by the most singular and complex affinities, and can be classed in groups under groups, in the same manner as varieties can be classed under species and sub-varieties under varieties, but with much higher grades of difference. It will be seen in my third work that these complex affinities and the rules for classification receive a ra~ional explanation on the principle of descent, together with modifications acquired through natural selection, entailing divergence of character and the extinction of intermediate forms. How inexplicable is the similar pattern of the hand of a man, the foot of a dog, the wing of a bat, the flipper of a seal, on the doctrine of independ ent acts of creation! how simply explained on the principle of the natural selection of successive slight variations in the diverging descendants from |