World of Scientific Discovery on Ernst Heinrich Haeckel
Ernst Haeckel was a naturalist who spent much of his career examining the relationship between evolutionary development (phylogeny) and the development of the embryo (ontogeny). Although the pursuit of this relationship often led Haeckel to advance some rather extreme theories, the environment of controversy and debate that surrounded him produced a number of genuine advances in the field of biology.
Haeckel was born in Potsdam, Prussia (now Germany), in 1834. His father, a lawyer and government official, decided early on that young Ernst would be a physician. Haeckel himself displayed little interest in medicine, preferring the biological sciences; he chose, however, to honor his father's wishes, enrolling at the University of Berlin's college of medicine. While a student, he took part in an expedition to the North Sea to study tiny sea creatures and, though he continued his medical coursework, his passion for biology was reignited. He obtained his M.D. in 1857 but practiced medicine for just one year before accepting a position at the University of Jena as lecturer (and eventually professor) of zoology.
Haeckel subscribed to the philosophical school of thought known as monism, which viewed the world as being a unified whole, and this philosophy formed the basis for much of his work. For example, one of Haeckel's earliest theories claimed that tiny one-celled animals called Radiolaria were created from inorganic matter through a kind of spontaneous crystallization, thus bridging the gap between organic and inorganic matter.
It was in 1859, the year he read Charles Darwin's The Origin of Species , that Haeckel turned his full attention toward the burgeoning science of evolution. He became a staunch advocate of Darwinism, the first such supporter in Germany and one of the first in Europe, using Darwin's findings as a springboard to launch his own hypotheses. He wrote a number of popular articles further describing organic and inorganic nature as being interconnected; these articles, though almost universally disputed, were widely read and soon earned Haeckel the reputation as an "expert" in his field.
Probably Haeckel's most famous theory was that of the relationship between embryonic and evolutionary development, a hypothesis first suggested by Karl von Beer. This theory, summarized in Haeckel's famous phrase "ontogeny recapitulates phylogeny," claimed that the stages an embryo went through during its development were representative of the stages of evolution; that is, that each embryonic stage represented the final stage of an evolutionary predecessor. This theory is based upon the knowledge that the earliest embryonic stages of many animals--such as turtles, chickens, and humans--resemble each other. With this theory as a starting point, Haeckel constructed a number of "ancestral trees" showing man's evolution from inorganic matter to lower animals to present day.
Although many of Haeckel's "unifying" theories were questionable, he was responsible for several important advances in his field. His suggestion that all life stemmed from a hypothetical two-layered creature called a Gastrea led to extensive research into the nature of many marine invertebrates, such as jellyfish, sponges, and medusae. His 1876 publication Die Perigenesis der Plasidule contained the first attempt to place heredity on a molecular level within the cell nucleus. He was the first to divide life into protozoan (one-celled) and metazoan (multi-celled) categories, and he was the first scientist to use the word "ecology" to describe the relationship between living organisms and the environment that surrounds them. On the other hand, another of Haeckel's quotable phrases, "politics is applied biology," was later adopted by Nazi propagandists. In fact, his theories were used by the Nazis as a justification for racism, nationalism, and social darwinism.
Haeckel retired from the University of Jena in 1909. He died in Jena on August 8, 1919. Haeckel left behind the Phyletic Museum at Jena, which he founded, and the Ernst Haeckel Haus, containing the bulk of his books and research as well as a number of mementos from his many expeditions.
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