deuterostomes vs protostomes
- protostomes - Annelida, Mollusca, Arthropoda
- spiral cell division
- mesoderm forms near blastospore
- blastospore >> mouth
- determinate embryonic development - cell fate fixed early on
- deuterostomes - Echinodermata, Hemichordata, Chordata
- radial cell division
- mesoderm forms opposite blastospore
- blastospore >> anus
- indeterminate embryonic development - cell fate fixed later in development
phylum Echinodermata - “spiny-skinned”
- level of organization - organ systems
- body symmetry - pentamerous (bilateral larvae, radial adults)
- alimentary structures - 2-hole tube
- triploblastic
- endoskeleton - ossicle bones on inside of organism
- calcified bones, not chitin
- water vascular system - uses water to move
- ring canal - surrounds center
- five radial canals - 1 on each leg
- madreporite - where water enters
- ampulla - controls the tube feet that make the organism move
- papula - simple gills that project out into the water
- Class Asteroidea - sea stars
- Class Ophiuroidea - brittle stars, can move w/ legs like cephalopod instead of tube feet
phylum Chordata - “cord”
- level of organization - organ systems
- body symmetry - bilateral
- alimentary structures - 2-hole tube
- triploblastic
- has dorsal hollow nerve cord, notochord, pharyngeal slits, postanal tail
- subphylum Urochordata - tunicates, sea squirts
- free-swimming larvae have chordate characteristics
- sessile adults only keep the pharyngeal slits
- subphylum Cephalochordata - lancelets
- subphylum Vertebrata - notochord replaced by bone during development
- contains fish, amphibians, reptiles, birds, mammals
- Class Agnatha - “w/o jaws”
- lampreys, hagfishes
- no jaws, paired appendages
- cartilaginous skeleton
- Class Chondrichthyes - “cartilaginous fish”
- sharks, skates, rays
- cartilaginous skeleton
- placoid scales
- Class Osteichthyes - “bony fish”
- gar, bass, coelacanth, perch, etc
- most diverse vertebrate class
- air/swim bladder
- operculum - covers the gills
- fins - caudal (tail), pectoral (sides), dorsal (top), pelvic (bottom), anal (bottom down, in front of caudal)
- Class Amphibia - “dual life”
- frogs, toads, salamanders
- lives on land, but must return to water for fertilization
- Class Reptilia - “to creep”
- turtles, snakes, lizards
- has dry skin w/ scales >> better suited for land
- has amniotic land egg
- Class Aves - birds
- feathers (replaced scales)
- forelimbs >> wings
- Class Mammalia - “beast”
- hair, body fat
- mammary glands
- diaphragm to force air into lungs
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