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symmetry in which the animal has a top and bottom side, but no front, back, left or right; symmetry in which similar parts branch out in all directions from a central line
symmetry in which an animal has two similar halves on either side of a central plane
the concentration of sensory and brain structures in the anterior end of the animal; animal has a head which proceds the rest of the body
animals that have a notochord, dorsal nerve chord, pharyngeal pouches, and a postanal tail in some stage of development
consists of muscle tissue and lies behind the posterior opening of the digestive tract
a rigid outer covering that protects the soft tissue of many animals (eg arthropods); limits the size and impedes the movement of the organism, and does not grow (has to be shed)
system that moves blood or a similar fluid through the body to supply oxygen and nutrients to the cells
open circulatory system
circulatory system in which blood like fluid is pumped from vessels in the body into the body cavity
closed circulatory system
circulatory system in which blood circulates through the body in tubular vessels
an organism that is born or hatched with the same appearance and way of life as it will when it is an adult; no larva stage
describing development of the mouth before development of the anus in arthropods, annelids, and mollusks
cleavage in which the cell divisions are parallel to or at right angles to the axis from one pole of the blastula to another
A type of embryonic development in protostomes that rigidly casts the developmental fate of each embryonic cell very early.
A type of embryonic development in deuterostomes, in which each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.
in protosomes; process in which cells divide rapidly in the blastocoel to form the mesoderm
in deuterosomes; process in which cells in the archenteron divide rapidly and roll outward into the blastocoel to form the mesoderm
body cavity in which the mesoderm lines the interior of the coelom but does not surround the exterior of the endodermic gut
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