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Crustacea. By: Zackery Zwicker , Benjamin O’Toole, Katey Murphy, Katie Gallant . Evolutionary origin .
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Crustacea By: ZackeryZwicker, Benjamin O’Toole, Katey Murphy, Katie Gallant
Evolutionary origin • Attempts have been made to construct a single hypothetical crustacean ancestor. Such an organism would have to possess: “elongated body, two pairs of appendages in front of the mouth, a pair of mandibles behind the mouth, and numerous trunk segments with appendages that form a continuous series of similar structure” • Cephalocaridais proposed as having a body plan from which all crustacean features could emerge Cephalocarida
The earliest crustacean fossils are ostrocods. • There is evidence from the Burgess shales that many crustacean features had already evolved during the Cambrian Period (542 million to 488.3 million years ago) Ostrocod fossil
Anatomy • Haemocoel: The body cavity in which blood flows • Sensory Organs: Compound eyes, statocysts (fluid filled cysts that sense direction of gravity), tactile hairs that respond to pressure or touch • Respiration: Diffusion or gills • Central nervous system: Brain and ventral nerve cord
Reproduction • Crustacea produce from eggs which have been fertilized by sperm • Most of the species are dioecious, there is a male and a female. • Most species brood their eggs, meaning they have many eggs that hatch at the same time.
Habitat Crustacea live in: • Oceans • Fresh water • Land • Many crustaceans are nocturnal • They spend their days hidden in a burrow, buried in the sand or sleeping in a crevice.
Diet • carnivores or scavengers • some are herbivores and detritivores • few classify as parasites • eat plants while some eat fish and other feed from the bottom of the ocean
Species of Crustacea • There are many species of Crustacea known, 67000, many of these are used for human consumption
Semibalanusbalanoides (Acorn Barnacle) • Grow up to 15 mm • Can produce up to 10,000 eggs • Sessile • No abdomen • Feed using Cirri
Talitrussaltator (Sand Hopper) • Compressed laterally • “Beach Fleas” • 8.2-6.5 mm long • Known for hopping patterns
Homarusamericanus (Atlantic Lobster) • 20-61 cm • .45-4.1 kg • Lives in cold shallow water • Same Order as crabs • Culinary Delicacy
Euphausiasuperba (Antarctic Krill) • Grows to 6 cm in length • Weigh up to 2 grams • Most abundant species • Bioluminescent
Bibliography • http://www.reefed.edu.au/home/explorer/animals/marine_invertebrates/crustaceans • http://www.britannica.com/EBchecked/topic/144848/crustacean/33813/Evolution-and-paleontology • http://whyevolutionistrue.files.wordpress.com/2010/03/cephalocarida.jpg • http://www.nhm.ac.uk/resources-rx/images/1017/silurian-silicified-ostracod-fossil_71605_1.jpg • http://www.britannica.com/EBchecked/topic/144848/crustacean/33813/Evolution-and-paleontology