Ernst Heinrich Philipp August Haeckel (February 16, 1834 – August 9, 1919), also written von Haeckel, was an eminent German biologist, naturalist, philosopher, physician, professor and artist who discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms, and coined many terms in biology, including anthropogeny, ecology, phylum, phylogeny, and the kingdom Protista. 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' entire evolutionary development, or phylogeny.
The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures (see: Kunstformen der Natur, "Artforms of Nature"). As a philosopher, Ernst Haeckel wrote Die Welträtsel (1895–1899, in English, The Riddle of the Universe, 1901), the genesis for the term "world riddle" (Welträtsel); and Freedom in Science and Teaching to support teaching evolution.
"First World War"
Haeckel was the first person known to use the term "First World War". Shortly after the start of the war Haeckel wrote:
“ There is no doubt that the course and character of the feared "European War"...will become the first world war in the full sense of the word. ”
Indianapolis Star, September 20, 1914
The "European War" became known as "The Great War", and it was not until 1931, with the beginning realization that another global war might be possible, that there is any other recorded use of the term "First World War".
Haeckel was a zoologist, an accomplished artist and illustrator, and later a professor of comparative anatomy. Although Haeckel's ideas are important to the history of evolutionary theory, and he was a competent invertebrate anatomist most famous for his work on radiolaria, many speculative concepts that he championed are now considered incorrect. For example, Haeckel described and named hypothetical ancestral microorganisms that have never been found.
He was one of the first to consider psychology as a branch of physiology. He also proposed many now ubiquitous terms including "anthropogeny", "phylum", "phylogeny", "ecology" ("oekologie"), and proposed the kingdom Protista in 1866. His chief interests lay in evolution and life development processes in general, including development of nonrandom form, which culminated in the beautifully illustrated Kunstformen der Natur (Art forms of nature). Haeckel did not support natural selection, rather believing in a Lamarckian inheritance of acquired characteristics (Lamarckism). 
Haeckel advanced a version of the earlier "recapitulation theory", previously set out by Étienne Serres in the 1820s and supported by followers of Geoffroy including Robert Edmond Grant, which proposed a link between ontogeny (development of form) and phylogeny (evolutionary descent), summed up by Haeckel in the phrase "ontogeny recapitulates phylogeny". His concept of recapitulation has been refuted in the form he gave it (now called "strong recapitulation"), in favour of the ideas first advanced by Karl Ernst von Baer. "Strong" recapitulation hypothesis views ontogeny as repeating forms of the ancestors, while "weak" recapitulation means that what is repeated (and built upon) is the ancestral embryonic development process. He supported the theory with embryo drawings that have since been shown to be oversimplified and in part inaccurate, and the theory is now considered an oversimplification of quite complicated relationships. Haeckel introduced the concept of "heterochrony", which is the change in timing of embryonic development over the course of evolution.
Haeckel was a flamboyant figure. He sometimes took great (and non-scientific) leaps from available evidence. For example, at the time that Darwin first published On the Origin of Species by Means of Natural Selection (1859), no remains of human ancestors had yet been found. Haeckel postulated that evidence of human evolution would be found in the Dutch East Indies (now Indonesia), and described these theoretical remains in great detail. He even named the as-of-yet unfound species, Pithecanthropus alalus, and charged his students to go find it. (Richard and Oskar Hertwig were two of Haeckel's many important students.)
One student did find the remains: a young Dutchman named Eugene Dubois went to the East Indies and dug up the remains of Java Man, the first human ancestral remains ever found. These remains originally carried Haeckel's Pithecanthropus label, though they were later reclassified as Homo erectus.
ACTINAE: Seeanemonen (Cnidaria: Anthozoa)
This species of animal, closely related to the corals, is sometimes called Pedifoggers or Suckers. They are most often found clinging to the bottom of the sea floor. Haeckel's illustration heightens their coloration while retaining their natural forms in meticulous detail. By setting the anemones within a three-dimensional habitat, Haeckel draws on his expertise as a landscape painter.
Sea anemones from Ernst Haeckel's Kunstformen der Natur (Artforms of Nature) of 1904.
BLASTOIDEA: Knospensterne (Echinodermata: Crinoidea)
"Nature exhibits a unity underlying an ever astonishing variety. There is an inherent geometry and symmetry in nature."
The specimens shown here, extinct relatives of starfish, exemplify Haeckel's observation. Moreover, the organization of the images on the page further accentuate the inherent symmetry and geometric formation of the organisms.
ECHINIDEA: Igelsterne (Echinodermata: Echinoidea)
This plate shows the life cycle of sea urchins from larva to adult. The two month-old urchin stage center with its long, symmetrical, kinetic projections is only a millimeter long. Haeckel's detailed depiction of the intricate forms and of the process of cell division is a credit to advances in design of the microscope, especially the apochromatic lens system, developed in 1868 by Ernst Abbe.
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More plates can be found here....