The Phylum Porifera is made up of sea sponges which are stationary plant like organisms found in the sea and coral reefs, sponges are simple organisms that lack true tissue but have generalized type of cells, they lack a complex digestive, respiratory, circulatory and nervous system, they are generally sessile as adults and spend their lives attached to a fixed point.
Cnidarians where the first organisms of movement, which have a nervous system called nerve net but no brain, their bodies have two cell layers, Cnidarians are mostly epitheliomuscular, whereby the epithelia cells contain contractile fibers that act as muscles. All cnidarians have a hydrostatic skeleton, a fluid like cavity surrounded by muscles; the muscles of …show more content…
The notochord is a semi-flexible rod that extends most of the length of the body, it stiffens the body, and acts as a support during movement and locomotion. Chordata have a bilateral symmetry, a segmented body, and segmented muscles, the notochord acts like an anchor to support the animal’s large body muscles. Chordates have four appendages in the shapes of legs, arms, wings or fins. Their internal skeleton has muscles attached that allow for a greater range of movement and the development of the body size. Chordates that lack bones have muscles that work against the notochord for