Romanes ' 1892 copy of Ernst Haeckel's allegedly fraudulent embryo drawings ( this version of the figure is often attributed incorrectly to Haeckel ).

Some version of Haeckel ’ s drawings can be found in many modern biology textbooks in discussions of the history of embryology, with clarification that these are no longer considered valid.

Romanes's 1892 copy of Ernst Haeckel's controversial embryo drawings ( this version of the figure is often attributed incorrectly to Haeckel ).

In 1866, following earlier proposals by Richard Owen and John Hogg, Ernst Haeckel proposed a third kingdom of life.

Haeckel promoted and popularized Charles Darwin's work in Germany and developed the controversial recapitulation theory (" ontogeny recapitulates phylogeny ") claiming that an individual organism's biological development, or ontogeny, parallels and summarizes its species ' evolutionary development, or phylogeny.

Haeckel ’ s illustrations show vertebrate embryos at different stages of development, which exhibit embryonic resemblance as support for evolution, recapitulation as evidence of the Biogenetic Law, and phenotypic divergence as evidence of von Baer ’ s laws.

Similarities can be seen along the first two rows ; the appearance of specialized characters in each species can be seen in the columns and a diagonal interpretation leads one to Haeckel ’ s idea of recapitulation.

The term, ‘ recapitulation ,’ has come to embody Haeckel ’ s Biogenetic Law, for embryonic development is a recapitulation of evolution.

As a response to Haeckel ’ s theory of recapitulation, von Baer enunciates his most notorious laws of development.

He compactly expressed the basis for a cultural recapitulation theory of education in the following claim, published in 1861, five years before Haeckel first published on the subject:

Haeckel used embryology extensively in his recapitulation theory, which embodied a progressive, almost linear model of evolution.

The concept of a biotope was first advocated by Ernst Haeckel ( 1834-1919 ): a German zoologist famous for the recapitulation theory.

Ernst Haeckel ( 1834 – 1919 ) became famous for his " recapitulation theory ", according to which each individual mirrors the evolution of the whole species during his life.

Early twentieth-century biologists like Ernst Haeckel viewed embryology as a recapitulation of evolution, which implies a kind of organising memory, and a few modern biologists, such as Rupert Sheldrake, influenced by Jungian ideas and by vitalism, have posited organising fields of life consisting of memories and drives.

This is the idea propagated by Ernst Haeckel as a source of evolutionary evidence ( recapitulation theory ).

Although the early embryos of different species exhibit similarities, Haeckel apparently exaggerated these similarities in support of his Recapitulation theory, sometimes known as the Biogenetic Law or " Ontogeny recapitulates phylogeny ".

Haeckel ’ s embryo drawings are primarily intended to express his idiosyncratic theory of embryonic development, the Biogenetic Law, which in turn assumes ( but is not crucial to ) the evolutionary concept of common descent.

Haeckel portrays a concrete demonstration of his Biogenetic Law through his ‘ Gastrea ’ theory, in which he argues that the early cup-shaped gastrula stage of development is a universal feature of multi-celled animals.

While often seen as rejecting Darwin's theory of branching evolution for a more linear Lamarckian " biogenic law " of progressive evolution, this is not accurate: Haeckel used the Lamarckian picture to describe the ontogenic and phylogenic history of the individual species, but agreed with Darwin about the branching nature of all species from one, or a few, original ancestors.

Haeckel formulated his theory as " Ontogeny recapitulates phylogeny ".

Historians write that most such political and economic commentators had only a superficial understanding of Darwin's scientific theory, and were as strongly influenced by other concepts about social progress and evolution, such as the Lamarckian ideas of Spencer and Haeckel, as they were by Darwin's work.

Ernst Haeckel ( 1866 ), in his endeavour to produce a synthesis of Darwin's theory with Lamarckism and Naturphilosophie, proposed that " ontogeny recapitulates phylogeny ," that is, the development of the embryo of every species ( ontogeny ) fully repeats the evolutionary development of that species ( phylogeny ), in Geoffroy's linear model rather than Darwin's idea of branching evolution.

* Konrad Körner: Linguistics and evolution theory ( Three essays by August Schleicher, Ernst Haeckel and Wilhelm Bleek ).

In the latter 19th century, the department of zoology taught evolutionary theory, with Carl Gegenbaur, Ernst Haeckel and others publishing detailed theories at the time of Darwin's " Origin of Species " ( 1858 ).

This important refutation of both preformation and the mosaic theory of Wilhelm Roux was to be subject to much discussion in the ensuing years, and caused friction among Driesch, Roux and Haeckel.

As a professor of anatomy at the University of Jena ( 1855 – 1873 ) and at the University of Heidelberg ( 1873 – 1903 ), Carl Gegenbaur was a strong supporter of Charles Darwin's theory of organic evolution, having taught and worked, beginning in 1858, with Ernst Haeckel, 8 years his junior.

Haeckel, in his book The History of Creation, devoted most of a chapter to the argument, and ended by proposing, perhaps with tongue slightly in cheek, to set up " a theory of the unsuitability of parts in organisms, as a counter-hypothesis to the old popular doctrine of the suitability of parts " (, p. 331 ).

Recent molecular and morphologic data add increasing evidence against this view, and the alternative colonial theory, also proposed by Haeckel in the 1870s is gaining widespread acceptance.

Haeckel introduced the concept of " heterochrony ", which is the change in timing of embryonic development over the course of evolution.

" He sometimes retorted sharply, " I am sorry to have to inform you that I do not believe in the Bible as a divine revelation, & therefore not in Jesus Christ as the Son of God ", and at other times was more guarded, telling a young count studying with Haeckel that " Science has nothing to do with Christ ; except in so far as the habit of scientific research makes a man cautious in admitting evidence.

Haeckel, the " indomitable worker ", quickly produced his History of Creation.

Ernst Haeckel | Haeckel's Paleontological Tree of Vertebrates ( c. 1879 ).</ br > The evolutionary history of species has been described as a " phylogenetic tree | tree ", with many branches arising from a single trunk.

His, in opposition to Haeckel, seeks to take human embryos out of the hands of Darwinist proponents.

Although Haeckel is proven right about the allantois, the utilization of Krause ’ s embryo as justification turns out to be problematic, for the embryo is that of a bird rather than a human.

Early phylogenetic tree by Ernst Haeckel | Haeckel, 1866

As a result of his letters and, no doubt, personal conversations, Huxley and Haeckel were convinced that, at the time he wrote Principles, he believed new species had arisen by natural methods.

These ( Nassellaria and Spumellaria ) were reported in the Report on Radiolaria ( 1887 ) written by Ernst Haeckel.

The word " ecology " (" Ökologie ") was coined in 1866 by the German scientist Ernst Haeckel ( 1834 – 1919 ).

The term " ecology " () is of a more recent origin and was first coined by the German biologist Ernst Haeckel in his book Generelle Morphologie der Organismen ( 1866 ).

The debate between Haeckel and His ultimately becomes fueled by the description of an embryo that Wilhelm Krause propels directly into the ongoing feud between Haeckel and His.

In response to Haeckel ’ s evolutionary claim that all vertebrates are essentially identical in the first month of embryonic life as proof of common descent, His responds by insisting that a more skilled observer would recognize even sooner that early embryos can be distinguished.

His completes his denunciation of Haeckel by pronouncing that Haeckel had “‘ relinquished the right to count as an equal in the company of serious researchers .’”

The first suggestion of fakery against Haeckel was made in late 1868 by Ludwig Rutimeyer in the Archiv fur Anthropogenie.

In a March 2000 issue of Natural History, Stephen Jay Gould argued that Haeckel “ exaggerated the similarities by idealizations and omissions .” As well, Gould argued that Haeckel ’ s drawings are simply inaccurate and falsified.

Phylogenetic tree suggested by Haeckel ( 1866 )

In 1866, Haeckel demonstrated that vertebrates could be divided based on their reproductive strategies, and that reptiles, birds and mammals were united by the amniotic egg.