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The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (), goes through stages resembling or representing successive adult stages in the evolution of the ...
Haeckel's aim was a reformed morphology with evolution as the organising principle of a cosmic synthesis unifying science, religion, and art. He was giving successful "popular lectures" on his ideas to students and townspeople in Jena , in an approach pioneered by his teacher Rudolf Virchow .
[15] Darwin's tree is not a tree of life, but rather a small portion created to show the principle of evolution. Because it shows relationships (phylogeny) and time (generations), it is a timetree. In contrast, Ernst Haeckel illustrated a phylogenetic tree (branching only) in 1866, not scaled to time, and of real species and higher taxa. In his ...
Gould laid to rest Haeckel's interpretation of evolutionary embryology, while Jacob set out an alternative theory. [10] This led to a second synthesis, [29] [30] at last including embryology as well as molecular genetics, phylogeny, and evolutionary biology to form evo-devo.
Haeckel and other German scientists would take the lead in launching an ambitious programme to reconstruct the evolutionary history of life based on morphology and embryology. [103] Darwin's theory succeeded in profoundly altering scientific opinion regarding the development of life and in producing a small philosophical revolution. [104]
Evolutionary progress as a tree of life. Ernst Haeckel, 1866 Lamarck's two-factor theory involves 1) a complexifying force that drives animal body plans towards higher levels (orthogenesis) creating a ladder of phyla, and 2) an adaptive force that causes animals with a given body plan to adapt to circumstances (use and disuse, inheritance of acquired characteristics), creating a diversity of ...
The discussions around Darwin's theory of evolution and Haeckel's monism gained prominence in the 1860s. Nonetheless, the question of a scientific worldview remained controversial, and Büchner's Kraft und Stoff remained a bestseller. The First World War and Haeckel's death in 1919 were
Evolution provides the field of biology with a solid scientific base. The significance of evolutionary theory is summarised by Theodosius Dobzhansky as "nothing in biology makes sense except in the light of evolution." [78] [79] Nevertheless, the theory of evolution is not static. There is much discussion within the scientific community ...