Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 15, 2025
Within the vertebrate stem there is, as we have already seen, so complete an agreement in structure and embryology that it is impossible to doubt their phylogenetic unity. In this case the evidence is much clearer and more abundant. The first three features are shared by the Vertebrates with the ascidia-larvae and the Prochordonia; the fourth is peculiar to them.
Each of us has, in the forty weeks properly speaking, in the first four weeks of his development in the womb, passed through the same series of transformations that our animal ancestors underwent in the course of millions of years. It is impossible to determine even approximately, in hundreds or even thousands of years, the real and absolute duration of the phylogenetic period.
This makes, for instance, baseball racially familiar, because it represents activities that were once and for a long time necessary for survival. We inherit tendencies of muscular cooerdination that have been of great racial utility. The best athletic sports and games a composed of these racially old elements, so that phylogenetic muscular history is of great importance.
Some forms have diverged more, and some less, from the original stem-form. This easily demonstrable fact illustrates very well the analogous case of the origin of the vertebrate species. Phylogenetic comparative philology here yields a strong support to phylogenetic comparative zoology.
The gradual acquirement of the erect position by the human infant admirably repeats this long phylogenetic evolution. At first the limbs are of almost no use in locomotion, but the fundamental trunk muscles with those that move the large joints are more or less spasmodically active. Then comes creeping, with use of the hip muscles, while all below the knee is useless, as also are the fingers.
Far more intricate are the processes of human embryology; in these are condensed and comprised thousands of the phylogenetic processes.
We must try to piece together a fairly complete picture of the series of our ancestors from the various phylogenetic fragments that we find in the different groups of the animal kingdom.
Prognosis will become definite in proportion to the physician's knowledge not only of the ontogenetic history of the individual patient, but also of the phylogenetic history of the race.
When we formulated "the law of the ontogenetic connection of systematically related forms," and determined the relative age of organs, we saw how it was possible to draw phylogenetic conclusions from the ontogenetic succession of systems of organs.
And just as the geological hypotheses that were ridiculed as dreams at the beginning of the nineteenth century are now universally admitted, so our phylogenetic hypotheses, which are still regarded as fantastic in certain quarters, will sooner or later be generally received. It is true that, as will soon appear, our task is not so simple as that of the geologist.
Word Of The Day
Others Looking