ENVI 21 Life in the Ocean

1
Fig 7.48
2

• Chordata
• Urochordata - Tunicates
• Thaliacea Salps
• Planktonic
• Transparent body with radial bands of muscle for
  locomotion
  
• Water enters through anterior incurrent siphon
  and is forced out through posterior excurrent
  siphon
  
• Solitary or colonial
• Larvacea Appendicularians
• Planktonic
• Superficially similar to tadpole larva
• Secrete mucus house for protection and feeding

3
Feeding Link
Fig 15.9
4

• Chordata
• Cephalocordata - Lancelets
• Possess all chordate characteristics throughout
  life (no backbone)
  
• Inhabit soft bottoms
• Suspension feeders (filter feeders)
• Gill slits used to filter particles out of water

5
Fig 7.49
Female Male
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• Vertebrata
• Share four chordate characteristics vertebral
  column (spine, backbone)
  
• Spine encloses and protects nerve cord (spinal
  cord)
  
• Anterior end of spinal cord brain protected by
  skull made of bone or cartilage

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• Fishes - Overview
• Oldest group of vertebrates (530 mya)
• 27,000 species (15,600 marine spp.)
• Three major groups
• Agnatha (Jawless fishes)
• Hagfishes, Lampreys
• Chondrichthyes (Cartilaginous fishes)
• Sharks, Rays, Skates, Ratfishes
• Osteichthyes (Bony fishes)
• Most familiar fish species

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Fig. 8.1
9

• Fishes - Overview
• Agnatha (Jawless fishes)
• Unpaired fins
• Lack jaws
• Round, muscular mouth with rows of teeth
• Hagfishes
• Scavengers (max length 80 cm) How do they
  feed?
  
• Dig burrows in areas with mud bottoms, usually
  cold water
  
• Attack hooked or trapped fish
• Capable of producing slime!!
• Very flexible (can tie selves into knots) Why?
• Exploited commercially Eelskin wallets
• Lampreys
• Most live in fresh water
• Attach to other fishes, rasp away sides and suck
  blood
  
• Also feed on benthic invertebrates

10
Fig. 8.2
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• Fishes - Overview
• Agnatha (Jawless fishes)
• Unpaired fins
• Lack jaws
• Round, muscular mouth with rows of teeth
• Hagfishes
• Scavengers (max length 80 cm) How do they
  feed?
  
• Dig burrows in areas with mud bottoms, usually
  cold water
  
• Attack hooked or trapped fish
• Capable of producing slime!!
• Very flexible (can tie selves into knots) Why?
• Exploited commercially Eelskin wallets
• Lampreys
• Most live in fresh water
• Attach to other fishes, rasp away sides and suck
  blood
  
• Also feed on benthic invertebrates

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• Fishes - Overview
• Chondrichthyes (Cartilaginous fishes)
• Skeleton of cartilage (more flexible than bone)
• Movable jaws
• Often contain well-developed teeth
• Mouth usually ventral
• Paired and unpaired fins
• Unpaired
• Dorsal
• Caudal
• Anal
• Paired
• Pectoral
• Pelvic
• Placoid scales
• Made of same material as teeth

Fig. 8.8
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• Fishes - Overview
• Chondrichthyes (Cartilaginous fishes)
• Sharks
• Fusiform body
• Heterocercal tail
• Typically two dorsal fins
• Pectoral fins usually large and pointed
• Five to seven gill slits
• Most sharks swim continuously to ventilate gills
• Whale shark Largest fish species (to 60 ft)
• Plankton feeder
• Most prevalent in tropical coastal waters
• Exploited and often overfished
• Fins for soup
• Meat
• Oil
• Skin ? Abrasive, Shagreen
• Cartilage ? Therapeutic

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Fig. 8.4