Phylum Chordata Worksheet (Biology) (Page 2 of 4) in pdf

Phylum Chordata Worksheet (Biology) Page 2

4-Class Chondrichthyes

(chondro = cartilage; ichthys = fish) which includes sharks and rays. They have a cartilage skeleton, not

bone. They are not buoyant like other fish so they must swim or sink. Like other fish they have a lateral line system which detects

differences in water pressure, the equivalent of our hearing.

5-Class Mammalia

(mamma, mammil = teat, nipple) is the mammals. Key characteristics of mammals are the presence of

fur/hair and mammary glands, derived from modified sweat glands, which produce milk for the young. Mammals have a diaphragm

to aid in respiration. They are endothermic. Most mammals bear live young

6-Class Osteichthyes

(osteo = bone) is the bony fish. This is the most numerous of all vertebrate classes. In fish, O

is exchanged

via the gills, which are covered by an operculum which helps to draw water across/through the gills. Their swim bladder is an air sac

used to control buoyancy, thus unlike the sharks, bony fish can hold still at any depth and not sink. Most fish we eat are in this class

(salmon, cod, tuna etc)

7-Class Reptilia

(reptili = creeping) , snakes, turtles, crocodiles, and lizards. Reptiles have scales and are dry to the touch. Their

eggs have leathery shells. Reptiles are exothermic (exo = out, outside), that is they maintain their body temperature through

external means such as sunning on a rock or seeking shade. Reptiles need less food/energy to live and live longer than a comparable-

*NOTE-TURTLES AND

sized mammal. There is a debate whether DINOSAURS were like modern day reptiles.

TORTOISES ARE REPLTILES, NOT AMPHIBIANS!!!!!!!!!!!!!!!!!!!!!

Phylum Chordata Worksheet (Biology) Page 2