Crustaceans

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(First Left: a crab, Middle: Thai Durban Hinge Beak Shrips, Far Right: Nauplius larva of a Barnacle, Down Left: Hermit Crab, Down Middle: Amphipod,Bottom right is a picture of a Beached Horse Shoe Crab.)

A. Organized Body Made of One or More Cells (McKenna S)

Crustaceans usually have a body that include two pairs of antennas, three pairs of feeding appendages, and typically three main sections; a head, a thorax, and an abdomen. The head contains the brain, eyes, and mouth parts. Different crustacecans have different mouth parts. Some crush or bite their food, where as others just push the food into their mouth. The typical thorax of a crustacean contains the heart, stomach, and organs needed for reproduction. Just like insects, crustaceans do not have a bony skeleton in their body. Since they do not have a bony skeleton, they have an outer skeleton, which is called an exoskeleton, of a hard material. Their exoskeletons have three layers, and the upper two are hardened by calcium. In some cases, the crustaceans exoskeleton is very hard and thick, but sometimes it is so thin that it is transparent. The muscles of a crustaceans are attached to the inside of the exoskeleton.
(Left: a dorsal view of a Lobster, Right: a close up of a lobster face)
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B. Obtain and Use Energy (McKenna Smith)

Crustaceans eat a variety of things depending on their particular needs. Some eat dead animals and living plants, where as others eat parasites and dead skin. Tiny crustaceans usually feed on bacteria, molds, dead animals, and plants. Lobsters are scavengers and active predators. They use their large claws to catch fish and smaller lobsters, to crush clams, and mussels. Some crustaceans have certain appendages in their mouth to enable them to handle and shred food, or filter tiny organisms and bits of decayed material from the water. When the oxygen combines with substances inside the digestive system in cells, energy is released.
(In the video: Arrow Crab Eating Bristle Worm)


C. Reproduction (Hank B)

Crustaceans are sexual and must find a mate to reproduce. All babies are born in eggs, Crustaceans do not have live birth. For a female lobster to mate, she must shed her protective shell and travel to her mate's den to reproduce. After the mating process the female lobster stays with the mate untill her protective shell grows back. Then she carries on with her life, carrying her eggs with her everywhere she goes. When the lobsters eggs are ready to hatch she releases them into the ocean and lets them swim away. The baby lobsters (or larva) do not stay with the mom; instead they are taken by the current and are tossed around until they are strong enough to swim away from the current. From there they go make dens and live their lives.
(In Video: a lobster molting)
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(Left: Video of a crab molting,Right: Crabs Mating.)

D. Grow and Develop (Hank B)

Crustaceans start out as larva, zoea and decapods. Each group of crustacean babies are produced by a different type of crustacean. When crustaceans start to grow old they start to look more and more like there parents. Sooner or later they are mini look-alikes of their birth parents. Crustaceans don't stop growing no matter how old they get. Crustaceans grow by "molting." Molting is when a crustacean out grow its old shell so they molt into a bigger shell which allows them to grow bigger. Most new born crustaceans molt a lot more then older crustacean. The older the crustacean is, the less they molt. Most new born crustaceans molt at least 15 to 20 molts in a 14 month time period. By then they are adult size. Crabs molt until they are adults then they stop growing. Lobster never stop growing and older crustaceans molt every couple of years.
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( Top left is a picture of a Crab Molting. Right is a picture of a thousand baby crabs.)

E. Respond to Stimuli (Ben R)

Eyes are among the several sense organs on which crustaceans and most other animals rely to give them information about their surroundings. Crustaceans' eyes are extremely sensitive to movement. Crustaceans usually have two compound eyes. The crustacean doesn't see a single image; it sees a vast amount. If a crustacean is trying to escape, his eyes must pick up movement. After its eyes pick up movement, it passes the information to the nervous system, which is the communications channel and control center for the body. The nervous system then tells its legs to move. This means that crustaceans can't even move without using their eyes.
(Picture Below: a Crustaceans eye)
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F. Exchange Gases with the Environment (Ben R)

Respiration is the process in which a body gets oxygen, distributes it to the cells, and then combines it with chemical foods. During the process carbon dioxide is produced and eventually released from the body. Crustaceans respire using their gills. Gills, also present in fish, absorb oxygen dissolved in water. Gill walls are so thin that oxygen can pass through them into blood, which then carries it to cells. A crustacean's gills are usually located behind its head. Some crustaceans absorb oxygen through gills on flattened parts of their legs. Others, including land-living types, lack gills and absorb oxygen through their entire body.
(Picture Below: Crustaceans Gills)
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Resources:
Gilpin, Daniel. Lobsters, Crabs and other Crustaceans. Minneapolis, MN: Compass Point Books, 2006.
Ricciuti, Edward R. Crustaceans. Woodbridge, CT: Blackbirch Press, Inc., 1994.

ReefScavengersCom. "Arrow Crab Eating Bristle Worm." YouTube. Sept. 12, 2007. Feb. 28, 2012
< http://www.youtube.com/watch?v=mpJ2uyUHR-o >

MrPuppy07. "Giant Spider Crab Molting (time-lapse)." YouTube. Jun. 23,2010. Feb. 27,2012
<http://www.youtube.com/watch?v=4QIgW639Oog&feature=player_embedded>

ZabbyLand. "Fighting Crustaceans." YouTube. Mar. 17, 2010. Feb. 28, 2012
< http://www.youtube.com/watch?v=2thqJtA5ULk&feature=player >

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