1. Phylum Chordata

2. Phylum Chordata All members of Phylum Chordata:
Have a dorsal nerve cord that becomes the basis for spinal cord/nervous system
Have a notochord at some point in development (a skeletal rod that runs under dorsal nerve)
Have a tail at some point in development
Have a muscular tube called a pharynx (used in feeding or respiration).
Gill slits some point in development

3. Vertebrata
Many members of Phylum Chordata have bony structures to surround and protect the dorsal nerve (they are vertebrates)
95% of Phylum Chordata are vertebrates
Can be ectotherms (body temperature regulated by outside environment – fish, reptiles, amphibians) or endotherms (regulate own body temperature – birds and mammals)
Classes of Vertebrates with living members:

4. Class Agnatha Jawless fish Long, tube-like, slimy bodies
Lack paired fins
Skeleton made of cartilage
Mouth is suction-like with sharp teeth. They clamp onto prey and suck out blood and bodily fluids.
Ex. Lamprey, hagfish

5. Class Chondrichthyes Skeleton made of cartilage
Paired gills for breathing underwater (gills filter oxygen from water)
Fins for swimming
Can have whip-like tails and potentially stingers
Moveable jaws with developed teeth
Some lay eggs, some give birth to live young
Ex. Sharks, skates, stingrays

6. Class Osteichthyes Bony fish Bone skeleton Gills for breathing
Paired fins
Thin, flexible scales
Have a gas-filled structure called a swim bladder, which allows for swimming at different depths.
Offspring produced via eggs laid by the female
Ex. Fish.

7. Class Amphibia Have two life stages:
Reproduction occurs in water. Eggs hatch here and tadpoles grow here. Breath through gills.
As adults, they move onto land and breath through lungs.
As adults, live near water, must keep skin moist. Can exchange gases through skin.
Carnivores: eat insects
Ex: Frogs, toads

8. Class Reptilia Terrestrial, although some spend time in water.
Have lungs
Thick scales that are water-proof and help prevent water loss
Lay amniotic eggs – eggs that provide a moist, self-contained environment for the embryo. Have leathery or calcium shells
Can ‘walk’ via limbs (unless you’re a snake), which have knee joints – allows for greater range of motion
Ex. Snakes, crocodiles, turtles

9. Class Aves Evolved from reptiles
Have feathers to provide insulation and protection (evolved from scales)
Wings for flight
Skeleton is very light weight – bones hollow
Beak-like structures
Very high metabolisms to allow for flight and to maintain temperature
Ex. All birds, including flightless ones like penguins and ostrich

10. Class Mammalia
Young are carried within the body and born alive (i.e. not laid in eggs)
Have fur/hair
Terrestrial, with lungs to breathe air
Females produce milk via mammary glands to feed young
Teeth replaced only once in life (milk teeth  adult teeth)
Four chambered heart
Lower jaw is a single bone