Epigenesis (biology)

Epigenesis or epigenesis (Greek epigenesis " subsequent emergence " ) term used in biology for the first time already advocated by Aristotle believes that emerge in the development of an organism new structures that were not already represented in the egg or the sperm. In contrast, temporarily stood the preformation, which was represented in ancient times by Anaxagoras and appeared again in the modern era in the 17th century.

History

Aristotle asked: " Why does an organism develops from a fertilized egg to the perfect adult form? " He assumed that the embryo can be seen from a shapeless mass, but argued that the raw material lacks the ability to make a complex organism produce. To the order of nature to explain their tendency to complexity and their targeted development, would be a greater formative principle, which he called eidos. Intermediary of medieval scholasticism, there was this view before until modern times.

In the 17th century, the Enlightenment endeavor argued to overcome such old dogmas and to understand the world by means of its own reason. A metaphysical Eidos had no place there. Instead, the preformation established as the only plausible view. The few advocates of epigenesis as René Descartes and William Harvey in the 17th century, Caspar Friedrich Wolff in the 18th century, therefore quickly came to the sidelines. Although Harvey ( 1651) and Wolff (1759 and 1768/69 ) report detailed embryological studies, however, failed to convince their contemporaries.

Not until the 19th century that the embryologists Christian Heinrich Pander (1817 ) and Karl Ernst von Baer ( 1828), to overcome the preformation and the epigenetic character of the embryonic to gain general recognition.

Definition of " epigenetics "

A linguistically related biological term that was only coined in the 20th century, is epigenetics. The adjective " epigenetic " can refer to both nouns depending on the context.