Modern features
The Late Neoproterozoic embryos
from China are complex and display
some modern features:
‘Furthermore, the embryos are
relatively complex and resemble
those of modern bilaterians such as
annelids and mollusks, but existed
tens of millions of years before the
Cambrian explosion.’10
The embryos display polar
lobes, asymmetrical bulges that allow
bilaterian embryos to form different
tissues as adults; these are common
in many modern mollusks.4 The
observations rule out an inorganic
origin and suggest the embryos are
from the same organism.10 Cell
division is asynchronous, a feature
common in modern embryos:
‘Asynchronous cell division is
common in modern embryos,
implying that sophisticated
mechanisms for differential cell
division timing and embryonic
cell lineage differentiation evolved
before 551 million years ago.’11
These findings show that, from
an evolutionary viewpoint sophisticated
processes of cell division evolved well
before the Cambrian ‘explosion of
life’. This poses many problems for
an evolutionary framework.
However, this in turn causes problems for the Young Earthers, one of whom has claimed that the pre-Cambrian fossils are not actually fossils of living creatures.
“‘Asynchronous cell division is
common in modern embryos,
implying that sophisticated
mechanisms for differential cell
division timing and embryonic
cell lineage differentiation evolved
before 551 million years ago.’11”
Interesting.