Invertebrates/Description of Crayfish/Clam/Starfish/Squid

Complete a virtual dissection of a crayfish, clam, starfish and squid.

1. Detailed drawing of the organism and its organs/systems/parts with labels.
   2. Written description of the following system including level of complexity, organs, and function.
   a. digestive system
   b. circulatory system (indicate if it has one)
   c. nervous system
   d. excretory system
   e. reproductive system
   f. integumentary system (structure ie skin, exoskeleton, shell, etc.)
   g. body plan
   3. Description of its unique habitat, diet and what distinguishes it as a mollusk, echinoderm, or arthropod.

-Cray Fish-

Crayfish are found in streams, rivers, lakes and ponds where the water contains adequate amounts of calcium salts. They are primarily nocturnal, hiding in crevices and under rocks during the day and emerging to feed at night. They will eat almost anything organic - plant or animal, living or dead. Crayfish are arthropod because, it has invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitin.

-Clam-

Hard clams inhabit the subtidal regions of bays and estuaries to approximately 15 meters in depth. They are generally found in mud flats and firm bottom areas consisting of sand or shell fragments. They can tolerate a wide range of salinities and live in brackish to saltwater conditions. Hard clams are extremely efficient filter feeders, and large hard clams can filter about a gallon of water per hour. As a result, they benefit water quality in coastal estuaries. Hard clams are also an important fisheries species.

-Starfish-

Starfish or sea stars are found in most of temperate and tropical oceans of the world. They are exclusively common and are bottom dwellers. Sea stars are found in a variety of habitats from the intertidal zone down to the bottom of deep seas but they are mainly found in shallow marine environments. They are found in sand, amongst rubble and on coral reefs and rocky bottoms below low tide as well as in estuaries and under the sand on beaches.

-Squid-

The squid is a member of the cephalopod family and is related to the octopus. Squid and other members of the cephalod family are actually mollusks that unlike clams or scallops lost most of their hard shells, although the squid does have the remnant of its shell which is called a cuttlebone. Squid are arrow shaped and have eight tentacles. They have the ability when excited to change their color, though they generally have a whitish hue.