CEPHALON-A trilobite's head

THORAX-A trilobite's body

PYGIDIUM-A trilobite's tail section

INVERTEBRATE-Animals lacking a spinal column

ARTHROPOD-Invertebrate animals having a jointed body and limbs

PLANKTON-Minute animals and plant life in a body of water

PLANKTONIC-Passively floating or weakly swimming thru the water,like plankton

PHOTOSYNTHESIS-A biochemical process in which plants, algae, and some bacteria harness the energy of light to produce food.

SYNTHESIS-The production of a substance by the union of chemical elements

CEPHALOPOD-Any members of a group of mollusks that have a tubular siphon under the head which are usually furnished with suckers,highly developed eyes,and usually a bag of inky fluid which can be ejected for defense or concealment

MOLLUSK-Invertebrate animals having a soft unsegmented body usually enclosed in a calcareous shell,such as snails and clams

CALCAREOUS-Resembling calcite or calcium,especially in hardness

ECHINODERM-Radically symmetrical marine animals,such as starfish and sea urchins

CRUSTACEAN-Any member of a large class of mostly aquatic arthropods that have a hard exoskeleton,or shell,a pair of often much modified appendages on each segment,and two pairs of antennae and that include lobsters,crabs,shrimp,wood lice,water fleas,and barnacles

SUTURES-Lines on a trilobite's cephalon (head) which separate the various sections of the cephalon,allowing the trilobite to molt (shed it's exoskeleton,or shell)

MERRIAM-WEBSTER'S DICTIONARY

Encyclopedia Britannica





STUDY QUESTIONS:
(See how many you can answer)
Answers are at the bottom of this page
DON'T PEEK!
1. Name 2 types of mollusks
2.What's another name for a trilobite's shell?
3.What does an invertebrate lack?
4.Name 3 types of crustaceans



"Trilobites were the first creatures with eyes? There were also many trilobites that didn't have eyes and were blind.The two types of trilobite eyes were: the schizochroal or compound eye,which had a number of closely packed lens units that were entirely covered by a single large cornea,and the holochroal,or aggregate eye, which consisted of separately encased lenses that were each covered by it's own cornea."

Schizochroal eye (Phacops)


Schizochroal eye (Coltraneia)


Holochroal eye (Asaphus)


Thanks to Ken LeBlanc and Steve Hess for the great looking trilobite eye photos

ANSWERS:
1.Snails,clams
2.Exoskeleton
3.A spinal column
4.Lobsters,crabs,shrimp,wood lice,
water fleas,barnacles