Marine Invertebrates (Part 3)

Phylogenetics Protostomes (mouth first) Deuterostomes (mouth second) Embryo cell division simple  complex

Lophophorates  Common feeding structure – lophophore (ciliated tentacles in rounded shape)  Three phyla:  Phoronida (worm-like)  Brachiopoda (clam-like)  Bryozoa/Ectoprocta (coral-like)

Bryozoans zooids

Bryozoans

Arrow Worms  Phylum Chaetognatha  only marine  few species  but abundant  important predators

Echinoderms  Phylum Echinodermata (“spiny skinned”)  All are marine  Larvae have bilateral symmetry, but adults have 5-way radial symmetry NOAA

Echinoderms  Distinctive features: water vascular system and tube feet (hydraulic)

Echinoderms Five classes:  Asteroidea - Sea stars (starfish)  Ophiuroidea - Brittle stars  Echinoidea - Sea urchins  Holothuroidea - Sea cucumbers  Crinoidea - Crinoids (sea lilies, feather stars)

Sea Stars

Sea Stars

NOAA

Brittle Stars

Sea Urchins test.jpg

Sea Urchins

Sea Cucumbers NOAA

Crinoids NOAA NOAA

Deep-Sea Echinoderms NOAA

Hemichordates  “Missing link” between echinoderms and chordates  Acorn worms ProtostomesDeuterostomes Embryo cell division

Hemichordates  2 common features with chordates

Invertebrate Chordates  Phylum Chordata  Subphylum Urochordata  Tunicates, salps, larvaceans  Subphylum Cephalochordata  Lancelets  Subphylum Vertebrata  Fishes, amphibians  Reptiles, birds  Mammals

Invertebrate Chordates  Common features of all chordates:  Dorsal (back) hollow nerve cord  Notochord (flexible support rod, becomes backbone in vertebrates)  Gill slits in the pharynx  Post-anal tail  Ventral heart Human embryo days

Tunicates (Sea Squirts)  Phylum Chordata  Subphylum Urochordata  Have all chordate features as larva, lose most as adults  Benthic as adults

Tunicates (Sea Squirts)

Salps, Larvaceans  Phylum Chordata  Subphylum Urochordata  Keep some/all chordate features as adults  Planktonic NOAA

Lancelets  Phylum Chordata  Subphylum Cephalochordata  Have all chordate features as adults, just lack backbone  Benthic

* * * typo in 7 th ed book (correct info here) Level of organization Symmetry CellularNone TissueRadial TissueBi-radial Organ systemBilateral Organ systemBilateral Organ systemBilateral Organ systemBilateral Organ systemBilateral Organ systemBilateral Organ systemRadial (as adult) Organ systemBilateral Organ systemBilateral