Chordates without Backbones
(Do not have a nerve cord)
- No skeleton inside their body
- Don't have small bones protecting nerve cord
Agnatha
- Jawless fish
- Internal skeleton made of cartilage
- Fin along their backs
- Mouth is a round sucker, lined with horny teeth
- All agnatha are parasite
- Cartilage is more flexible than bone.
Chondrichthyes
- Skeleton made of cartilage
- They have proper jaws and teeth
- Have fins on both sides of their bodies as well as along their backs
Osteichthyes
- They are fish
- Have fins on the back and sides of their body
- Have proper draws and teeth
- Their skeleton is made of bone
Amphibians
- Amphibians live both in and out of water
- Their eggs are laid in water
- The larvae or tadpoles must live in water because they breathe through gills
- The body changes shapes in a process called metamorphosis allowing adults to live on land, using their lungs
- Amphibians can also breathe through their skin (skin must be moist)
Reptiles
- Reptiles are ectothermic
- Have dry, scaly skin
- They breathe using their lungs
- Lay eggs with a leathery shell on land
Aves
- Aves is the biological name for birds
- Birds have feathers covering their body
- Lay hard - shelled eggs
- All birds have wings
- Birds are endothermic (generate their own heat)
Mammals
- Hair covering their body
- Feed their babies milk produced by the mother
- Endothermic
- Have 3 subclasses: Placentals, Monotremes, Marsupials