Whoever does not just look like a savage, the phenomena of nature as if they were free of any bond of coherence can no longer believe that man is the work of a separate act of creation. He will be forced to admit that the close resemblance of the human embryo with that, for example, a dog - the con-struction of his skull, its members and its ossa-ture following the same plane as that of other mammals, independently of the uses to which the parties may be affected - the occasional reappearance of various structures, such as muscles that man does not normally, but which are common to quadrupeds - and a crowd of analogous facts - all this leads to the most obvious conclusion that man is with other mammals, the co-descendant of a common ancestor.
We have seen that man continues to make indi-vidual differences in all parts of his body and his intellectual faculties. These differences or variations seem to be induced by the same general causes, and obey the same laws as in lower animals. In both cases predominate similar laws of inheritance. Man tends to increase at a rate greater than its livelihoods and, accordingly, it is subjected to a severe struggle for existence and natural selection had to exert its effects on any
what was found in his range. A succession of strongly marked variations of a similar nature is not necessary; slight fluctuating differences in the individual sufficient work of natural selection, and we have not the slightest reason to suppose that, in the same species all parts of the organization tend to vary in the same degree. We can be assured that the inherited effects of use or non-use extended parts will have done much in the same direction as natural selection. Formerly important changes, though no longer of any use special long to transmit. When a part is modified, other parts change under the principle of correlation [... ]. Something can be attributed to direct action and denies challenge-living conditions surrounding such a food abundant, heat or humidity, and, lastly, many characters of little importance physiological, and some who have a considera-ble, have been acquired through sexual selection. [... ] Thanks
his means that we have just explained, aided perhaps by others who have not
been discovered yet, the man rose to his present condition. But since reaching the quality of man, it has diversified into distinct races, or as they might call a more appropriate sub-species. [... ] All races agree on so many structural details of no importance and so many mental peculiarities, they can not be explained by inheritance from a common ancestor, an ancestor and thus characterized should probably be ranked among the men. Do not assume that the divergence of each race com-pared with other races, and all from a common core can be traced back to one in any pair of ancestors. Instead, at each stage of change, all individuals who were in one way or another better suited to their living conditions, albeit to different degrees, had to survive in greater numbers than the less well adapted . [... ]
If we consider the embryological structure of man - the homologies he presents with the lower animals - it retains primitive traits and Returns which it is subject, we can recall in imagination a part of the former condition of our very first ancestors-and we can approximately place them in their proper place in the zoological series. We thus learn that man descends from a hairy quadruped and fitted with a tail, probably arbori-school in his habits, and resident of the Old World. This creature, though a naturalist
had reviewed its entire structure would have been classified as safe quadumanous-ment that even older ancestor of apes from Old World and New. The Quadrum-ties and all mammals superiors probably derived from a archaic marsupial, and the latter through a long series of forms diversified, derived from a creature type
amphibian, and this in turn an animal resembling a fish. In the dark confusion of the past, we can see that the Premiere ancestor of all vertebrates must have been an aquatic animal, provided with gills, the two sexes on the same individual, and possessing the most important organs of the body ( such as brain and heart) imperfectly developed ment or not. This animal seems to have resembled the larvae of existing marine ascidians more than any other known form.
The top level of our brains and our moral disposition is the greatest difficulty that arises after we have been led to this conclusion on the origin of man. But those who accept the principle of evolution must see that the mental capacity of higher animals, which are similar in nature to those rights, though so different in degree, are capable of progress. Thus, the interval between the mental abilities of one of the higher apes and those of a fish, or those of an ant and an insect scales, is immense. How-ing their development makes no special difference, because in our domestic animals, the mental faculties are certainly variable, and the variations are inherited. Nobody doubts their extreme importance for the animals to the state of nature. The conditions, therefore, are favorable to their development through natural selection. We can extend the same conclusion at the man's intelligence must have been for him of paramount importance, even at a very early period, making it able to invent and use language, to make weapons , of tools, traps, etc.. through which, with the help of his social habits, he long ago became the most dominant of all living creatures. [... ]
The main conclusion I have reached in this book, namely that man is descended from some lower form of organization, will, I regret to think, highly unpleasant for many. But there can be little doubt that we descended from barbarians. The astonishment which I felt at seeing for the first time a group of Fuegians on a wild coast so rough, I'll never forget it as soon as I suddenly came to mind this thought: such were our ancestors. [... ]
Man may be excused for feeling some pride at having risen, although this is not due to his own efforts, to the very summit of the organic scale, and the fact that he be so high, instead of being placed at the origin, can give hope for a still higher destiny in the distant future. However we are not here concerned with hopes or fears, but only the truth, as far as our reason allows us to discover it, and I did my best to produce the evidence. We must recognized, however, that it me sem-ble, that man with all his noble qualities, with sympathy he feels towards the most deprived, with the goodwill it extends not only to other men, but to the humblest of creatures Vivan-thy, with his divine intelligence that has penetrated the movements and constitution of the solar system - with all these capabilities sublime - the man still bears in his bodily construction footprint indelible his lowly origin.
