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Re: please share your knowledge
>From: supercalafragilisticexpialadocious <email@example.com>
> BTW, what is the notochord in the Cambrian???
A notochord is a particular anatomical structure found in embryonic
vertebrates, tunicates, and a few other obscure groups. It is a
cartiligenous bar along the dorsal midline, immediately interior
to the nerve chord. In those animals that have one in a free-living
stage of life, it provides an elastic base against which locomotory
muscles can operate. (In vertebrates, it is *replaced* by the
centra of the vertebral column).
The earliest known fossils with clear evidence for a notochord
are from the Cambrian Period. The most spectacular of these fossils
closely resembles the living chordate _Amphioxus_. In addition,
it is now known that the conodont animal was a chordate.
[Chordate means "an animal with a notochord"].
The peace of God be with you.