On the Origin of Species integrated with a model of variation. This modern evolutionary synthesis had been dubbed Neo Darwinian Evolution because it encompasses Charles Darwin's theories of evolution with Gregor Mendel's theories of genetic inheritance. Chapter VI begins by saying the next three chapters will address possible objections to the theory, the first being that often no intermediate forms between closely related species are found, though the theory implies such forms must have existed. As Darwin noted, "Firstly, why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in
On the Origin of Species embryonic stages. These factors also supported his theory of descent with modification. The final chapter "Recapitulation and Conclusion" reviews points from earlier chapters, and Darwin concludes by hoping that his theory might produce revolutionary changes in many fields of natural history. He suggests that psychology will be put on a new foundation and implies the relevance of his theory to the first appearance of humanity with the sentence that "Light will be thrown on the origin of man and his history." Darwin ends with a passage that became well known and much quoted: It is interesting to contemplate an entangled