- C CLv 61 decade agoFavorite Answer
Two major theories on embryogenesis existed prior to the 18th century: the theory of preformation and the theory of epigenesis. The preformationists believe that the adult form originated from a miniature form contained within the original zygote. Using the human as an example, the fetus would gradually grow in size and eventually become a newborn infant; however the shape and form of the fetus did not alter significantly during the process. Under this theory, the fetus contains every matured organ that the developed form would have, including future fetuses within the current developing fetus, just like matryoshka dolls.
(I may not have used the best jargon in the translation... such as '成體' or '小型幼體'... it was a while ago when I took developmental biology...)Source(s): me
- 1 decade ago
18 centuries ago, Western biologists there were two foetal development process the theory are "first into theory" (preformation) and "new theory" (epigenesis). First into theory that adult is fertilized eggs from the small larva. The human as an example, small fetus will gradually become bigger in the end infant, the process in the fetus shape there was no major changes. But the fetus contains adult possession that everything, including the fetus fetus is like the Russian dolls.
我不太確定= =如果不是的話就是下面這個= = 開頭不太一樣=0=
Before 18th century, the Western biology educational world has two kind of embryonic development process the theory, respectively is “becomes theory (preformation) first” and “the epigenesis” (epigenesis).Cheng Lun thought first the adult is comes from in the fertilized egg small young animal.Take the human body as the example, the small embryo can increase gradually, finally becomes the baby, but in process embryo's shape not too sweeping change.Moreover these embryos include all which the adult has, including embryo's in embryo, likely is the Russian babies is same.Source(s): 自己