title: The "Biogenetic Law" in zoology: from Ernst Haeckel's formulation to current approaches.
abstract: 150 years ago, in 1866, Ernst Haeckel published a book in two volumes called "Generelle Morphologie der Organismen" (General Morphology of Organisms) in which he formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny. Here we describe Haeckel's original idea and follow its development in the thinking of two scientists inspired by Haeckel, Alexei Sewertzoff and Adolf Naef. Sewertzoff and Naef initially approached the problem of reformulating Haeckel's law in similar ways, and formulated comparable hypotheses at a purely descriptive level. But their theoretical viewpoints were crucially different. While Sewertzoff laid the foundations for a Darwinian evolutionary morphology and is regarded as a forerunner of the Modern Synthesis, Naef was one of the most important figures in 'idealistic morphology', usually seen as a type of anti-Darwinism. Both Naef and Sewertzoff aimed to revise Haeckel's biogenetic law and came to comparable conclusions at the empirical level. We end our review with a brief look at the present situation in which molecular data are used to test the "hour-glass model", which can be seen as a modern version of the biogenetic law.
authors.affiliation: Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität, Erbertstr. 1, 07743, Jena, Germany. Lennart.Olsson@uni-jena.de.
authors.forename: Lennart
authors.identifier: http://orcid.org/0000-0002-2696-6423
authors.initials: L
authors.lastname: Olsson
authors.affiliation: AG Biologiedidaktik, Friedrich-Schiller-Universität, Bienenhaus, Am Steiger 3, 07743, Jena, Germany.|University ITMO, Chaikovsky Str. 11/2, 191187, St. Petersburg, Russia.
authors.forename: Georgy S
authors.initials: GS
authors.lastname: Levit
authors.affiliation: AG Biologiedidaktik, Friedrich-Schiller-Universität, Bienenhaus, Am Steiger 3, 07743, Jena, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Hoßfeld
mesh_terms: D000818:Animals; D005075:Biological Evolution; D015509:Developmental Biology / Q000266:history*; D005858:Germany; D049672:History, 19th Century; D049673:History, 20th Century; D007858:Learning; D008954:Models, Biological; D010802:Phylogeny; D012641:Selection, Genetic; D015046:Zoology
keywords: Atavisms; Heterochrony; Homeobox; Ontogeny; Phylogeny