Aquarium Essay


Organism 1,2,3,6,7,8,9 and 10 are from the phylum Chordata. All Chordates shared four
major characteristics; a notochord, which provides a skeletal support, a dorsal hollow
nerve cord, which develop into the central nerve system, pharyngeal slits, which are
openings in the pharynx that develop into gills, and a post-anal tail.

Organism 2,7 and 8 are the phylum Mollusca. The animals in this category share many
characteristics which are bilateral symmetry,two cell layers, tissues and organs, lack a
cavity, posses a through gut with a mouth and anus monomeric and highly variable bodies,
may posses shell and calcareous spicules, has a nervous system with a circum-oesophageal
ring, ganglia and paired nerve chords, open circulatory systems with a heart and an aorta,
has gaseous exchange organs called ctenidial gills, reproduce sexually, feed on a wide
variety of materials and live in most environments.

Organism 4 is an Arthropoda. Arthropods have a body covered in chitinous cuticle that
hardens into an exoskeleton, composed of somites (Metamerism), jointed appendages, ventral
nerve cord with ganglia at each segment, open circulatory system and a bilateral symmetric
body. Most Arthropods reproduce sexually; however some insects are parthenogenetic.

Organism 4 was Porifera. Poriferans are commonly sponges which are sedentary by nature,
most of them are marine sponges, cylindrical, have radial symmetry, have a body wall
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