Crustaceans

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Crustaceans

• By Mrs. Hendrie

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Crustaceans

• Crustaceans are members of a large class of
  animals with segmented bodies
• Crustaceans belong to the same major division, or
  phylum, of the animal kingdom as insects and
  spiders
• Included among them are lobsters, shrimp, crabs,
  wood lice, barnacles, water fleas, and many other
  animals

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Lobsters

• Lobsters have teeth-like structures in their
  stomach, which grind partially digested food.
  This structure is called the gastric mill.
• It thrives in cold, shallow waters where there
  are many rocks and other places to hide from
  predators
• It feeds on fish, small crustaceans, and mollusks

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Lobsters continued

• They range from 8 to 24 in n length and 1 to 9 lb
  in weight, but have been known to reach lengths
  of well over 1 yd and weigh as much as 44 lb,
  making this the heaviest marine crustacean in the
  world.
• An average adult is about 9 inches long and
  weighs 1.5 to 2 lb
• Main natural predator is the codfish, but other
  enemies include haddock, certain species of
  seals, flounder, and other lobsters
• American lobsters molt two to three times per
  year while young, but only once a year or less
  often when fully mature, which is about four to
  seven years old
• The old shell is often eaten for calcium recovery
  and the leftovers are sometimes buried
• More info http//www.clearwater.ca/media/documents
  /qa_hardshelllobster.pdf

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Diagram of a Lobster

• Many Lobsters have eight walking legs and two
  large claws (hence the name Decapod-10)
• Their swimmerets and tail fin are used for
  swimming in the ocean
• The larger claw, crusher claw, is used for
  crushing its food
• Antenna have hairs that are covered with multiple
  nerve cells that can detect odors
• The larger, thicker hairs are found along the
  edges . These hairs control the flow of water,
  containing odor molecules, to the inner sensory
  hairs
• The mouth is also used to push gravel and sand,
  and to carry small rocks away
• A lobster actually chews its food in its stomach,
  rather than its mouth

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Crabs

• Male fiddler crabs have one large claw, which
  they wave in the air to impress females and
  intimidate other males
• If you use some imagination, it looks like the
  male is playing a fiddle, or violin
• They feed on a diet comprising of algae,
  mollusks, worms, other crustaceans, fungi,
  bacteria and detritus (cord grass)
• The teeth of a crab are in its stomach.

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Crabs continued

• The biggest crab till date was found in Maryland.
  It was a male and measured nine inches
• After losing its claw, a crab can grow it back
• Crabs are also arthropods i.e. they have
  segmented appendages, just like a cockroach,
  butterfly, housefly, etc.
• The male crabs have narrow abdomens, while the
  female crabs have broader abdomens (for carrying
  eggs)

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Diagram of a Crab

• All crabs have eight walking legs
• As you can see the fiddler crab has one small
  claw and one large claw
• The large claw is for attracting females and
  crushing its food
• The center of its body is called the carapace

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Shrimp

• Shrimp differ from their close relatives, the
  lobsters and crabs, in that they are primarily
  swimmers rather than crawlers
• The body is covered with a smooth exoskeleton
  that must be shed as it grows
• The shrimp's exoskeleton tends to be thinner than
  most of the other crustaceans it is grayish and
  almost transparent
• They may grow as long as 9 inches, but most are
  smaller

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Shrimp continued

• Shrimp swim forward by paddling their abdominal
  swimmerets and can move backward with swift
  strokes of their fanlike tails.
• A shrimps heart is in its head
• They feed on algae and zooplankton

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Diagram of Shrimp

• Decapod with ten jointed legs on the thorax
• Well-developed swimmerets on the abdominal
  segments
• Pair of antenna
• 2 Uropods for swimming
• 1 Telson to steer them in the water
• Carapace which protects their head

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Facts about Crustaceans

• The largest kind of crustacean, the giant spider
  crab of Japan, measures up to 12 feet across
  between its outstretched claws.
• The smallest crustaceans are water fleas they are
  as small as 1/125 inch long
• The horseshoe crab is not a true crab, it is
  more closely related to scorpions than crabs
• Another interesting fact is that you can eat
  horseshoe crabs! (there isnt much meat)
• Barnacles are a delicacy in parts of Europe and
  South America. Crayfish are a centerpiece of
  spicy Creole and Cajun cuisines of Louisiana.
• Other fun facts go to http//www.hightechscience.o
  rg/funfacts.htm

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Comparing Crustaceans
Lobster Crab Shrimp
Large claw to crush their prey Large claw to crush their prey and attract females No claws
crawler crawler swimmer
Heart in abdomen Heart in carapace Heart in its head (carapace)
Molt antenna Decapod swimmerets Molt antenna Decapod swimmerets Molt antenna Decapod swimmerets
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Work Cited

• http//www.buzzle.com/articles/what-do-shrimp-eat.
  html
• http//www.clearwater.ca/media/documents/qa_hardsh
  elllobster.pdf
• http//www.dnr.sc.gov/marine/pub/seascience/images
  /shrimppartslg.gif
• http//education.yahoo.com/reference/encyclopedia/
  entry/shrimp
• http//www.enchantedlearning.com/subjects/inverteb
  rates/crustacean/label/fiddlercrab/answers.GIF
• http//www.gma.org/lobsters/lobsterbottomview.gif
• http//www.Howstuffworks.com
• http//lifestyle.iloveindia.com/lounge/facts-about
  -crab-1884.html

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Work Cited continued

• http//www.nefsc.noaa.gov/faq/
• http//www.planetinverts.com/cardinal_shrimp/cardi
  nal_shrimp_web3.jpg
• http//thesociallens.files.wordpress.com/2009/05/f
  ull-size_blue-crab.jpg
• http//www.science.unsw.edu.au/media/pics/site/ima
  gecache/CF835EA7C3B6CA4EB835093D23ED7F55.jpg
• http//www.windvd.org/resources.php?artid227