ENVI 21 Life in the Ocean

Download Report

Transcript ENVI 21 Life in the Ocean

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