PSEUDOCOELOMATE PHYLA

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PSEUDOCOELOMATE PHYLA
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CHARACTERISTICS

• Pseudocoelom
• space between gut and mesoderm parts of body wall
• space filled with fluid
• for differentiation of systems
• storage of waste products
• used as hydrostatic skeleton

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CHARACTERISTICS

• Cuticle
• acellular outer covering, over epidermis
• for protection against water loss or gain
• resistant to environmental chemicals

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CHARACTERISTICS

• Systems
• Dont have
• circulatory system
• respiratory system
• true skeletal system
• Do have
• Reproduction usually dioecious
• excretion protonephridia
• digestive complete
• muscles longitudinal only
• nerve ladder like with cerebral ganglia
• hydrostatic skeleton for movement

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PSEUDOCOELOMATE PHYLA

• Major
• Nematoda
• Rotifera
• Gastrotricha
• Nematomorpha
• Acanthocephala

• Minor (see text)
• Kinorhyncha
• Loricifera
• Priapulida
• Entoprocta

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Nematoda(roundworms)

• numerous, slender, cylindrical
• Unsegmented
• found in all types of habitats, terrestrial,
  marine, freshwater
• dioecious

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Nematodes - Characteristics

• Sense organs Bristles for Chemoreception
• Amphids unique
• Digestive system Complete
• Excretion
• Free living Marine species Renette gland
• Freshwater and Terrestrial - Tubular

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Ascaris lumbricoides(intestinal roundworm)

• - 64 of SE is infected
• may produce 200,000
• eggs/day
• life cycle
• ingested by humans as eggs
• intestinal larvae get into blood
• carried to lungs
• get coughed up and swallowed
• adult develops in small intestine
• eggs released through feces

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Ascaris
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Necatur americanus(hookworm)

• 1910 40 of SE infected
• 1963 4 infected
• life cycle
• penetrates skin on bottom of feet
• gets into blood and goes to lungs
• coughed up and swallowed
• attached to intestine
• produce anticoagulant and feed on blood

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Trichinella spiralis(trichinosis)

• very bad to contract
• get it from eating undercooked pork
• humans not in natural cycle
• in humans encysts in muscles, causes aching
• life cycle
• one host
• larvae feed in intestine
• adults live in intestine

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Enterobius vermicularis(pin worm)

• in 46 of population
• most common parasite in humans in world
• life cycle
• adults in folds of anus
• female emerges at night to lay eggs
• eggs get under nails, are also airborne
• larvae develop in digestive tract
• not very serious, more of a nuisance

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Filariasis
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Dog Heartworm
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Phylum Rotifera(rotifers)

• have a corona with cilia, like norelco shaver
  head
• no cilia elsewhere
• with forked foot with cement glands for
  attachment
• complex digestive structures such as mastax

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Rotifer Reproductiondioecious

• Parthenogenesis

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Phylum Gastrotricha(Gastrotrichs)

• ventrally flattened with bands of cilia
• also have adhesive glands on foot
• with spiny, scaly or warty cuticle
• no corona or mastax, etc.
• hermaphroditic, male system in some reduced
• reproduction similar to that of rotifers

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Phylum Nematomorpha(horse hair worms)

• larvae parasitic in insects like grasshoppers
• adults aquatic, but do not feed
• life cycle
• eggs ingested by grasshopper
• larva develops in gut
• emerges when host near water
• develops into adult
• dioecious

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Phylum Acanthacephala(spiny headed worms)

• have characteristic spiny proboscis
• have no digestive tract
• life cycle
• larvae found in arthropod, such as insect
• all adults endoparasites in guts of vertebrates
• Dioecious
• Acanthor Larva