Chapter 17 and 18
Phylum Hemichordata (acorn worms,
pterobranches) deuterostomes, pharyngeal gill
slits
Phylum Chordata
Pharynx
Dorsal hollow nerve cord
Notochord
Post-anal tail
Subphylum Urochordata
e.g. sea squirts/tunicates
Subphylum Cephalochordata
e.g. lancelet
paedomorphosis
Chapter 18
Subphylum Craniata
Chordates with a head (brain with support(skull))
One kind of invertebrate craniate: hagfish
Slime glands
Jawless (agnathan)
Lampreys are agnathans with a simple vertebral
column
Bloodsucking parasites on other fish
Gnathostomes (jawed vertebrates)
Opposable jaws are modified pharyngeal gill
arches
Class Chondrichthyes (cartilagenous fish: sharks,
skates, rays, ratfish)
Hard scales, shark teeth are scales
Class Osteichthyes (bony fish: operculum (gill
cover), swim bladder, usually a bony skeleton)
Operculum used to maintain current of water
over gills
Bony fish in two major groups:
Ray-finned fish (chondrosteans (includes
sturgeon) and teleosts (big, big group))
lobe-finned fish (coelacanths and lungfish)
the lobe-fin clade includes coelacanths,
lungfish, and tetrapods
transition to land
air-breathing and legs
Amniotes
Diapsid branch
Reptiles and Birds
Synapsid branch
Only extant members are mammals
Mammals
a) mammary glands (modified sweat glands)
b) hair
c) specialized teeth (within one mammals(e.g.
incisors, molars, canines)) among different
mammals (rodents and artiodactyl and
primates all very different)
d) legs oriented under the body (compared to
reptiles with legs coming out at side) with
mammals, the legs more directly support
body weight
e) endothermic/high metabolic rate
three big groups of extant mammals
1) Monotremes (egg-laying mammals) platypus,
echidna (all in Australia)
2) Marsupials (marsupium (pouch)) most found in
Australia, some are found in South America and
North America (opossum)
3) Eutherians (placental mammals) (extended
period of development in uterus with placenta)
Orders of eutherians
a) Insectivora (shrews, moles, tenrecs, etc.)
b) Chiroptera (bats, Microchiroptera
(echolocation), Megachiroptera)
c) Carnivora (diverse group, have carnassial
teeth) know difference between a carnivore and a
carnivoran (member of Order Carnivora)
d)Perissodactyla (odd-toed hooved mammals;
horses, rhinos, tapirs, zebras)
e) Artiodactyla (even-toed hooved mammals)
f) Cetacea (whales, dolphins, porpoises)
toothed and baleen whales
gXenarthra (few check teeth or no teeth; sloths,
armadillos, giant anteaters)
h) Lagomorpha (rabbits, hares, pikas)
i) Rodentia (see textbook) incisors grow
continuously, adaptation for gnawing
j) Primates (prosimians, monkeys, apes (no tail))
hands for climbing, stereoscopic vision, large
brains
k) Proboscidea (elephants)
l) Sirenia (manatees)
Birds Archosaurs (dinosaurs, crocodilians)
Flight
Feathers (insulation and for flight)
Forelimbs modified into wings
Endothermic/high metabolic rate
Honeycomb bones
Beak (lighter than toothed jaw)
Gizzard (internal chewing organ)
Sternum is modified as a keel
Forelimb muscles are relocated
Feathers (contour ( a hard shaft, adapted for
flight))
(down feathers, lack a hard shaft, adapted for
insulation)