Biological Classification - The Eight Classes of the Subphylum Vertebrata

The video tutorial explains the classification of vertebrates into eight classes: Agnatha, Placodermi, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia. Each class is described with its unique characteristics, such as jawless fish in Agnatha, extinct jawed fish in Placodermi, cartilaginous fish in Chondrichthyes, bony fish in Osteichthyes, amphibians with aquatic larvae, reptiles with dry skin, birds with feathers, and mammals with hair and live birth.

Which class of vertebrates includes fish that lack jaws and paired fins?

• Osteichthyes

• Agnatha

• Chondrichthyes

• Placodermi

What is a distinctive feature of bony fish in the class Osteichthyes?

• They have a notochord as adults.

• They possess a swim bladder.

• They have cartilaginous skeletons.

• They lack paired fins.

Which class of vertebrates is characterized by cold-blooded animals with dry, thick skin?

• Reptilia

• Mammalia

• Aves

• Amphibia

What is a unique feature of birds in the class Aves?

• They have a beak with no teeth.

• They are cold-blooded.

• They lay eggs with leathery shells.

• They have a three-chambered heart.

Which class of vertebrates includes animals that typically give birth to live young and nurse them with milk?

• Aves

• Mammalia

• Reptilia

• Amphibia