Biomedical Engineering Reference
In-Depth Information
hypothesis. Now, biophotonic research of growth and development
has a field theory to test against the biology.
5.1 Introduction
In
The Origin of Species by Means of Natural Selection, or the
Preservation of Favoured Races in the Struggle for Life
, Darwin
presented his work in 1858 to the Linnaean Society, causing an
explosion within the halls of science. Proving the pen is mightier
than the sword, Darwin created no less of a revolution
outside
the
scientificdomain.Antagonistswereleftreeling.Darwin'sdiscussion
of embryos thrust embryologists and histologists into the spotlight
at the turn of the 20th century (see Fig. 5.1a,b). Today epigenesis
and preformation are opposite views to explain the development
of the individual form. Science sees the recent debate between the
two camps in a wider perspective, going back to Aristotle and his
interest in chicken embryos. In this view 20th-century genetics
represents a new form of pre-determinism, while the 21st century
may be a new era of epigenesis, where the cosmos itself is seen
as the cradle of life. Stem cell research reveals the fate of cells is
not gene specific. Each stem cell can be harvested and cultured into
a number of adult cell types. Differentiation is normally specific
Figure 5.1
(a) Human embryo after six weeks and (b) histological film of
mouse embryo after 10 days (credit: Wikimedia). Resemblance of embryos
led Darwin to state that a 'community of embryonic structure reveals
community of descent.'
