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Biology Class - Phylum Project

Topic: phylum Loricifera

Notes: Anatomy and Morphology (What are the major physical characteristics?):

They have a head, mouth, and digestive system as well as a lorcia. (armour-like lorcia - having a protective external shell or case of encircling plicae.) No circulatory system & no endocrine system. Many of the larvae are acoelomate, (acoelomate: Lacking a fluid filled body cavity) with some adults being pseudocoelomate, and some remaining acoelomate. '''Very complex and plastic life cycles of pliciloricids include also paedogenetic stages with different forms of parthenogenetic reproduction. The animals have two sexes as adults.''' Development is generally direct, though there are so called Higgins-larvae, which differ from adults in several respects.

Characteristics: 1)Bilaterally symmetrical. 2)Body has more than two cell layers and includes tissues and organs. 3)Has a body cavity, and a straight through gut. 4)Body has three distinct regions, a head a neck and a trunk. 5)Has one pair of gonads = gonochoristic. 6)Has a well developed nervous system with a brain and nerve ganglia. 7)Has a distinct larval stage. 8)Lives in marine environments.

Ecology and habitat (Where are members of the phylum found? What do they eat? Do things eat them?): Three species of Loricifera have been found in the sediments at the bottom of the L'Atalante basin in Mediterranean Sea. (more than 3,000 meters down) The first multicellular organisms known to spend their entire lives in an oxygen-free environment. They are able to do this because they rely on hydrogenosomes (or similar organelles) instead of on mitochondria for energy. The newly reported animals complete their life cycle in the total absence of light and oxygen, and they are less than a millimeter in size. Where they inhabit a nearly salt-saturated brine that, because of its density (> 1.2 g/cm³), does not mix with the waters above. Despite such harsh conditions, this anoxic and sulphidic environment is teeming with microbial life, both chemosynthetic prokaryotes that are primary producers, and a broad diversity of eukaryotic heterotrophs at the next trophic level.

Interesting facts about members of the Phylum:

Examples of species with the phylum with pictues: Armorloricus, Australoricus, Nanaloricus, Phoeniciloricus, Pliciloricus, Rugiloricus, and Titaniloricus.

Source list: At easybib.com