Explain how that difference arose in embryonic development from the primary embryonic tissues. The earth worm is a coelomate and the Ascaris is a pseudo coelomate. As such, the earthworm has mesoderm in contact with the gut during development, the Ascaris does not. In order for the muscle to form, mesoderm must be present. The predator can eat all of a large meal reducing the number of times it must hunt allowing energy to go into reproduction and not survival 13.
Chordates have four shared derived characters.
One is the hollow dorsal nerve cord. Pharyngeal slits 2. Briefly outline in a series of steps, the formation of the dorsal hollow nerve cord. 1. ridges develop in the ectoderm 2. Any three 1.