Transcript ENVI 21 Life in the Ocean

I.
Nematoda
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Free living and parasitic forms
Cosmopolitan/Ubiquitous
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Mostly in sediments (free living) or hosts (parasitic)
Common in fine muds
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Organic rich areas
Described species – 12,000+
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May be up to 500,000 species total!
Extremely abundant!!
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Up to hundreds of individuals per ml of sediment
90,000 in one rotting apple (not marine)
Hydrostatic skeleton
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Longitudinal muscles only
Move by whipping back and forth
II. Other Worms
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Sipuncula (Peanut worms)
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Exclusively marine (250+ species)
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Most common in shallow water
Unsegmented bodies up to 35 cm long
Studded introvert used for locomotion
Cryptic
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Burrow in sediments or hide in shelters
Deposit feeders
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Consume detritus and microbes
II. Other Worms
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Sipuncula (Peanut worms)
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Exclusively marine (250+ species)
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Most common in shallow water
Unsegmented bodies up to 35 cm long
Studded introvert used for locomotion
Cryptic
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Burrow in sediments or hide in shelters
Deposit feeders
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Consume detritus and microbes
Fig. 7.3
II. Other Worms
B.
Echiura (Spoon worms)
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Exclusively marine (~150 species)
Deposit feeders
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Live in burrows
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Feed with non-retractable proboscis
U-shaped or L-shaped
Typically small but may get large in deep sea
II. Other Worms
C.
Pogonophora (Beard worms)
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Long, thin worms (~135 species)
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Most common in deep sea
No mouth or gut
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Not parasitic
Anterior end of body is tuft of up to several
thousand tentacles
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Tentacles absorb dissolved nutrients
Symbiotic bacteria utilize nutrients to manufacture
food
Vestimentifera
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Large deep-sea animals
Found at many hydrothermal vents
Fig. 7.17
II. Other Worms
C.
Pogonophora (Beard worms)
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Long, thin worms (~135 species)
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Most common in deep sea
No mouth or gut
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Not parasitic
Anterior end of body is tuft of up to several
thousand tentacles
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Tentacles absorb dissolved nutrients
Symbiotic bacteria utilize nutrients to manufacture
food
Vestimentifera
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Large deep-sea animals
Found at many hydrothermal vents
III. Annelida
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Segmented worms
Body composed of repeated segments
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Gut runs through all segments in body cavity
(coelom)**
Coelom filled with fluid – hydrostatic skeleton
Longitudinal and radial muscles
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Efficient locomotion and burrowing
More than 15,000 species
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Cosmopolitan
III. Annelida
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Polychaeta
10,000+ species (mostly marine)
Body segments bear pairs of parapodia
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Parapodia used for locomotion, feeding
Often tipped with setae
Closed circulatory system**
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Efficient transport of blood, gases
Gas exchange
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Small species exchange gases across body wall
Large species have gills for gas exchange
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Highly vascularized with capillaries and thin body walls
Fig. 7.15
III. Annelida
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Polychaeta
Spawning – Palolo worm
Larva = Trochophore
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Band of cilia around body; tuft on apex
Same larval stage in Mollusca, Echiura, Sipuncula
Diverse lifestyles
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Free-living predators
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Often well-developed eyes and sense organs, jaws
Burrowing deposit feeders
Burrowing suspension feeders
Tube building suspension feeders
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Tubes may be calcium carbonate, agglutinated or parchment
Solitary
Colonial
III. Annelida
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Polychaeta
Larva = Trochophore
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Band of cilia around body; tuft on apex
Same larval stage in Mollusca, Echiura, Sipuncula
Diverse lifestyles
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Free-living predators
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Often well-developed eyes and sense organs, jaws
Burrowing deposit feeders
Burrowing suspension feeders
Tube building suspension feeders
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Tubes may be calcium carbonate, agglutinated or parchment
Solitary
Colonial
III. Annelida
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Polychaeta
Larva = Trochophore
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Band of cilia around body; tuft on apex
Same larval stage in Mollusca, Echiura, Sipuncula
Diverse lifestyles
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Free-living predators
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Often well-developed eyes and sense organs, jaws
Burrowing deposit feeders
Burrowing suspension feeders
Tube building suspension feeders
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Tubes may be calcium carbonate, agglutinated or parchment
Solitary
Colonial