Posted by
Jochen Fromm-3 on
URL: http://friam.383.s1.nabble.com/Cambrian-Explosion-tp521557p521563.html
There is no doubt that environmental changes and
chemical/physical stress are among the causes for the
Cambrian explosion (Snowball Earth, glaciation, etc.).
Certainly there is a connection between "emergence"
and "extinction", between complexity and catastrophes.
My question was more about the "how" (how does the
underlying code define the development of individuals?
is there such a code for the body plan?) and
less about the "why".
The form or "architecture" of plants for example can
be described well by fractals, IFS and L-Systems. Skeletons
and animal bodies have a certain amount of self-similarity,
too: a typical modern animal body has a certain amount of limbs
(2-6 legs or arms), and each limb has further sub-limbs
(2-6 toes or fingers). Therefore it must be possible to
describe bodies and their development with simple iterative
rules. I wonder what kind of rule set or code is really used?
The "three-lobed" trilobite for example, one of the first
animals that appeared in the Cambrian period has a very
simple repetitive head-body/thorax-tail structure, where the
body is composed of many similar repetitive segments.
http://en.wikipedia.org/wiki/Trilobite-J.