SUBPHYLUMS Three Types #1 Urochordata (Tunicates and Seaquirts) Considered as the invertebrate chordata As an adult they have an reduced nervous system and loss notochord No definite head Filter feeders 2

#2 Cephalochordata (lancelets) Also a invertebrate chordata-only 29 species Filter feeders with cilia to carrier particles into their mouths #3 Vertebrata (vertebrates) Roughly 43,000 species Have vertebral column and a backbone that is the supporting axis holding up the body and protecting the spinal cord 3

Chordata Classes #1 Agnathans (Agnatha) –jawless vertebrates (lampreys and hagfish) #2Chondrichthyes-cartilaginous fish (sharks, skates, rays, and chimaeras) Have teeth and small scales Have separate gill openings #3Osteichthyes: Bony fish o Bony skeletons and jaws 4

#4 Amphibia (Amphibians): (Frogs, Toads, salamanders, and newts) Live near or in fresh water Four-legged except Order Apoda-legless Life cycle: tadpole –adult and most undergo metamorphosis when changing into an adult 5

#5 Reptila: Reptiles (turtles, tortoises, tuatara, snakes, lizards, alligators, crocodiles, and caimans) Evolved from primitive amphibians Ones with legs, are usually stronger and larger than amphibians, enable many reptiles to carry their bodies off the ground Lungs better developed than amphibians, and have larger rib muscles allowing for better lung ventilation 4 chambered heart and most are cold blooded Lay eggs that include both the shelled egg and the embryonic membrane –amnion (amphibians lack) Internally fertilized 6

#6 Aves –Birds  4 chambered heart but warm-blooded  Simple excretory system, highly developed brain, and respiratory system  Lack teeth, and the bones are hollow (light for flight)  All have feathers and many fly and lots of birds migrate  Internal fertilization  Lay eggs with calcium carbonate shells, after development they peck at the shell with an egg tooth that cracks the shell so the chicks become free 7

#7 Mammalia: Mammals  Evolved from an early group of reptiles  Warm-blooded and have a 4 chambered heart  Have hair and fur for insulation, also layers of fat or blubber under their skin –for warmth  Have a diaphragm, the muscle under the rib cage that reptiles do not have –improves breathing  Sweat glands help regulate the body temperature and rid body of wastes  Scent glands produce chemical substances that help mammals communicate with each other  Most have highly developed teeth 8

Mammalia continued Specific skeletal features are unique, such as an enlarged cerebrum Reproduce by internal fertilization Only the Order Monotremes lay eggs, most give birth to young and nourish them by milk produced in mammary glands of the female 9

Orders of Class Mammalia #1 Monotremata: Montremes #2 Marsupalia: Marsupials #3 The Placental Mammals (several orders) 10