The Vertebrates: Phylum Chordatawww.onacd.ca

Major Classes of Vertebrates

Above: Class Amphibia: Includes all amphibians (frogs, toads, salamanders)

Below: Class Aves: Includes all birds

Above: Class Sauropsida: Includes the reptiles Below: Class Mammalia: Includes all mammals

Class Chondrichthyes: Includes all cartilaginous fish ex. shark

Class Osteichthyes: Includes all bony fish

Characteristics of All Vertebrates• Coelomate and bilaterally symmetrical which

allows for complex body systems• Have backbones with a protected spinal column

and endoskeleton• Advanced central nervous system with large brain

with skull• Have unequivocal head, eyes and sensory organs• Complex heart and circulatory systems• Muscular system consists of mostly paired

masses• Possess a special outer covering• Have 1 or 2 pairs of appendages• Are found on land and water

Adaptations of VertebratesClass Amphibia

• Have gills and very primitive lungs to exchange gasses as they live half of their life in water and half on land

• Can also take in gasses through their moist skin

• Lay eggs in the water after sexual reproduction which develop into tadpoles

Adaptations of VertebratesClass Aves : The Birds

Adaptations for Flight• Feathers• 4 chambered heart• Hollow bones for

strength without weight

• Large sternum for wings to attach and put pressure

• Lungs and air sacs are used to improve gas exchange at thin altitudes

Bony Fishes• Skeleton is made up of

bone• Have a swim bladder to

regulate buoyancy• Perform external

fertilization and lay eggs• Have been very

successful because they can reproduce in large quantities

Cartilaginous Fishes• Skeleton is made up of

cartilage• Do not have a swim

bladders• Perform internal

fertilization and bear live young

What’s the Difference?

Endotherms• Warm blooded• Body temperature

remains constant regardless of external temperature changes

• Endotherms can regulate their metabolic rate and are more independent of their environments

Ectotherms• Cold blooded• Body temperature varies

with the surrounding environment

• Cannot regulate their metabolic rate very well

What’s the Difference?

Characteristics of Mammals• Warm blooded• Air breathing• 4 legged vertebrates• Possess skin with hair

and sweat glands• Have teeth with a

jawbone• Fleshy lips• Diaphragm• 4 chambered heart• Have a brain and middle

ear• Bear live young• Have mammary glands

Ecological Roles of Vertebrates• All are part of the food

chain• Amphibians contribute to

wetland ecology, prey on insects and devour algae and dead plants

• Reptiles are predators of pests

• Birds control insect and vermin populations as well as act as pollinators

• Mammals aerate soil and are sensitive to environmental changes