They are the most familiar echinoderms.
They are the most important predators in many marine ecosystems.
They have a pigmented epidermis.
They are the only echinoderms that are fully sessile.
DNA studies can be used to make all of the following conclusions except that A. the gibbon ape line diverged about 15 million years ago. B. orangutans split off about 10 million years ago. C. gorilla lineage diverged about 8 million years ago. D. chimpanzee line diverged less than 6 million years ago. modern man remained changeless for the last 1 million years.
Breaking into parts and regenerating new animals from them.
Breaking into equal parts which become two whole animals.
Developing from trochophore larvae.
External sexual reproduction produces fertilized eggs.
Fertilized eggs develop into free-swimming, bilaterally symmetrical larvae.
Madreporite --> stone canal --> lateral canal --> ring canal --> radial canal --> tube foot
Madreporite --> lateral canal --> ring canal --> radial canal --> stone canal --> tube foot
Madreporite --> stone canal --> ring canal --> lateral canal --> radial canal --> tube foot
Madreporite --> stone canal --> ring canal --> radial canal --> tube foot
Madreporite --> stone canal --> radial canal --> ring canal --> tube foot
Bilateral symmetrical larvae.
Radial symmetrical adults.
Regeneration of a lost body part.
Pentamerous body plan
Larvae are sedentary, adults are plantonic.
Ctenidia—secretion of the shell (when present)
Visceral mass—houses organs of digestion, excretion, reproduction
Nephrostome—collection of nitrogenous wastes
Nudibranchs—extensive gills in mantle cavity
Bivalvia—reduced head and no radula
Polyplacophora—eight calcareous plates
Cephalopoda—closed circulatory system
Circular muscles contract—segment becomes thin and long
Longitudinal muscles contract—segment becomes thick and short
Fluid in coelom—provides a hydrostatic skeleton
Chaetae—provides gas exchange surface for body muscles
Brachiopods are often misidentified as bivalves.
Brachiopods were much more diverse in the past.
As in bivalves, the valves in brachiopods are lateral (left and right) to the body axis.
Most brachiopods are sessile (attached).
The lophophore resides within the brachiopod's shells.
Offers some protection
Reduces water loss
Allows for muscle attachment sites inside the skeleton
Does not impose limitations on body size
Provides a strong, flexible framework
Malpighian tubules—adult insects
Book lungs—larval insects
A flexible rod to which muscles are attached which allowed moving their backs laterally
An internal endoskeleton development
A skin covering the entire body to prevent desiccation
A hard shell encasing the body
A nerve cord.
A postanal tail.
Adult forms are sessile and filter feeding.
Adult forms secrete a tunic composed mainly of cellulose.
Adult forms are not segmented.
Larval forms show all chordate characteristics.
Larval forms feed actively.
A distinctive head or skull.
An open circulatory system.
Sharks and bony fish.
Skates and rays.