Chapter

The Egg

Jan Sapp

in Genesis

Published in print September 2003 | ISBN: 9780195156195
Published online September 2007 | e-ISBN: 9780199790340 | DOI: http://dx.doi.org/10.1093/acprof:oso/9780195156195.003.0010
 The Egg

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This chapter discusses the diverging views of embryologists and geneticists about heredity and evolution. The two main reasons for this stemmed from research started in the 19th century. First, experimental embryologists were not concerned with adaptive changes to adult organisms. They were not concerned with the differences between individual varieties and species, but rather with the larger similarities and differences in the structural plans underlying different organismic types. They were interested in the form of the embryo and in the orderly changes during development — in how the parts of the organisms come together in space and time. Second, while geneticists and neo-Darwinian evolutionists maintained that changes in the nuclear chromosomal genes of eggs and sperm were the basis of evolution, many embryologists insisted that the cytoplasm of the egg played the primary role in heredity and development.

Keywords: embryologists; geneticists; egg cytoplasm; maternal inheritance; cellular differentiation; cytoplasmic evolution; heredity

Chapter.  5755 words. 

Subjects: Evolutionary Biology

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