Read The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919

The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919

Ernst Haeckel

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Description:Excerpt from the book...In turning from the embryology to the phylogeny of man--from thedevelopment of the individual to that of the species--we must bear inmind the direct causal connection that exists between these two mainbranches of the science of human evolution. This important causalnexus finds its simplest expression in "the fundamental law of organicdevelopment," the content and purport of which we have fullyconsidered in the first chapter. According to this biogenetic law,ontogeny is a brief and condensed recapitulation of phylogeny. If thiscompendious reproduction were complete in all cases, it would be veryeasy to construct the whole story of evolution on an embryonic basis.When we wanted to know the ancestors of any higher organism, and,therefore, of man--to know from what forms the race as a whole hasbeen evolved we should merely have to follow the series of forms inthe development of the individual from the ovum; we could then regardeach of the successive forms as the representative of an extinctancestral form. However, this direct application of ontogenetic factsto phylogenetic ideas is possible, without limitations, only in a verysmall section of the animal kingdom. There are, it is true, still anumber of lower invertebrates (for instance, some of the Zoophyta andVermalia) in which we are justified in recognising at once eachembryonic form as the historical reproduction, or silhouette, as itwere, of an extinct ancestor. But in the great majority of theanimals, and in the case of man, this is impossible, because theembryonic forms themselves have been modified through the change ofthe conditions of existence, and have lost their original character tosome extent. During the immeasurable course of organic history, themany millions of years during which life was developing on our planet,secondary changes of the embryonic forms have taken place in mostanimals. The young of animals (not only detached larvae, but also theembryos enclosed in the womb) may be modified by the influence of theenvironment, just as well as the mature organisms are by adaptation tothe conditions of life; even species are altered during the embryonicdevelopment. Moreover, it is an advantage for all higher organisms(and the advantage is greater the more advanced they are) to curtailand simplify the original course of development, and thus toobliterate the traces of their ancestors. The higher the individualorganism is in the animal kingdom, the less completely does itreproduce in its embryonic development the series of its ancestors,for reasons that are as yet only partly known to us. The fact iseasily proved by comparing the different developments of higher andlower animals in any single stem.We have made it easy for you to find a PDF Ebooks without any digging. And by having access to our ebooks online or by storing it on your computer, you have convenient answers with The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919. To get started finding The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919, you are right to find our website which has a comprehensive collection of manuals listed.
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Description: Excerpt from the book...In turning from the embryology to the phylogeny of man--from thedevelopment of the individual to that of the species--we must bear inmind the direct causal connection that exists between these two mainbranches of the science of human evolution. This important causalnexus finds its simplest expression in "the fundamental law of organicdevelopment," the content and purport of which we have fullyconsidered in the first chapter. According to this biogenetic law,ontogeny is a brief and condensed recapitulation of phylogeny. If thiscompendious reproduction were complete in all cases, it would be veryeasy to construct the whole story of evolution on an embryonic basis.When we wanted to know the ancestors of any higher organism, and,therefore, of man--to know from what forms the race as a whole hasbeen evolved we should merely have to follow the series of forms inthe development of the individual from the ovum; we could then regardeach of the successive forms as the representative of an extinctancestral form. However, this direct application of ontogenetic factsto phylogenetic ideas is possible, without limitations, only in a verysmall section of the animal kingdom. There are, it is true, still anumber of lower invertebrates (for instance, some of the Zoophyta andVermalia) in which we are justified in recognising at once eachembryonic form as the historical reproduction, or silhouette, as itwere, of an extinct ancestor. But in the great majority of theanimals, and in the case of man, this is impossible, because theembryonic forms themselves have been modified through the change ofthe conditions of existence, and have lost their original character tosome extent. During the immeasurable course of organic history, themany millions of years during which life was developing on our planet,secondary changes of the embryonic forms have taken place in mostanimals. The young of animals (not only detached larvae, but also theembryos enclosed in the womb) may be modified by the influence of theenvironment, just as well as the mature organisms are by adaptation tothe conditions of life; even species are altered during the embryonicdevelopment. Moreover, it is an advantage for all higher organisms(and the advantage is greater the more advanced they are) to curtailand simplify the original course of development, and thus toobliterate the traces of their ancestors. The higher the individualorganism is in the animal kingdom, the less completely does itreproduce in its embryonic development the series of its ancestors,for reasons that are as yet only partly known to us. The fact iseasily proved by comparing the different developments of higher andlower animals in any single stem.We have made it easy for you to find a PDF Ebooks without any digging. And by having access to our ebooks online or by storing it on your computer, you have convenient answers with The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919. To get started finding The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919, you are right to find our website which has a comprehensive collection of manuals listed.
Our library is the biggest of these that have literally hundreds of thousands of different products represented.

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The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919

The Evolution of Man — Volume 2 - Haeckel, Ernst Heinrich Philipp August, 1834-1919

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