Invertebrates

Octopus Video

Phylum Echinodermata

1. Asteroidea (Sea Stars) – Keystone Species

Phylum Echinodermata2. Ophiuroidea (Brittle Stars, Serpent Stars)

Phylum Echinodermata3. Echinoidea (Sea Urchins, Sand Dollars, Sea Biscuts)

• Endoskeleton has a round, rigid test• Moveable spines and pedicellarie• Have 5 rows of ambulacral grooves• Herbivores – eat attached or drifting seaweed and seagrasses

Phylum Echinodermata3. Echinoidea (Sea Urchins, Sand Dollars, Sea Biscuts)

Phylum Echinodermata4. Holothuroidea (Sea Cucumbers)

• Lack spines and obvious radial symmetry• Endoskeleton reduced to small spicules in skin• Have a respiratory tree• Deposit and filter feeders• Evisceration

Phylum Echinodermata4. Holothuroidea (Sea Cucumbers)

Phylum Echinodermata4. Holothuroidea (Sea Cucumbers)

Enypniastes eximia

Phylum Echinodermata5. Crinoidea (Sea Feathers and Lilies)

• Suspension feeders

• Capture food with tube feet and mucus

• Ciliated ambulacral grooves mood food to mouth

Video Clip

Phylum Echinodermata5. Crinoidea (Sea Feathers and Lilies)

• Feather stars – Unstalked• Cosmopolitan, but especially abundant in warm water

• Capable of swimming

• Sea lilies – Stalked• Uncommon, restricted to deep water

Phylum Hemichordata

Phylum Hemichordata• Hemichordates

• Mainly Acorn Worms• Deposit feeders• Live in U-shaped burrow – process lots of sediment• Get organic matter from mucus secreting proboscis

Phylum Hemichordata• Hemichordates

• Mainly Acorn Worms• Deposit feeders• Live in U-shaped burrow – process lots of sediment• Get organic matter from mucus secreting proboscis

Phylum Chordata

Phylum Chordata• Four Major Characteristics

• Three Subphyla1. Urochordata – Tunicates

2. Cephalochordata – Lancelets

3. Vertebrata – Vertebrates

Phylum Chordata

1. Urochordata - TunicatesA. Ascidiacea (Class) – Sea squirts

• Only sessile chordates• Body covered by tunic (gelatinous outer covering)• Active suspension feeders (filter feeders)

• Water pumped in through incurrent siphon and out through excurrent siphon

• Particles filtered out by feeding basket (pharynx)• Planktonic tadpole larva

• Possesses all four chordate characteristics• Doesn’t feed – resorbs notochord and tail at settlement

Phylum Chordata

Phylum Chordata1. Urochordata - Tunicates

B. Thaliacea – Salps• Planktonic

• Transparent body with radial bands of muscle for locomotion

• Solitary or colonial

Phylum Chordata

1. Urochordata - TunicatesC. Larvacea – Appendicularians

• Planktonic

• Superficially similar to tadpole larva

• Secrete mucus “house” for protection and feedingFeedingLink

Phylum Chordata

B. 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

Fig 7.49

Female

Male

Phylum ChordataC. 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

1. Fishes• Oldest group of vertebrates (530 mya)

• 27,000+ species (15,600+ marine spp.)• Three major groups