Term | Definition |
Phylum Chordata
(Chordates) | Most members of this phylum are vertebrates with bony skeletons and backbones.
Most common on land & in water.
Many fewer chordate species than invertebrate species. |
A Dorsal Nerve Cord | Nerves branch to all parts of the body. |
A Notocord | Rod of cartilage that runs along the dorsal length of the body. |
Gill Slits | In the pharynx (throat). |
Amnion | Fluid-filled sac around the embryo. |
Chordate Respiration | Fish are the only vertebrates adapted to live their lives entirely in water. They obtain oxygen from the water through their gills.
Reptiles, birds & mammals have lung-base respiratory systems. |
External Fertilization | The egg & sperm meet outside the body.
Ex. Sharks, frogs |
Internal Fertilization | The egg & sperm meet inside the body
Ex. Reptiles, birds, mammals
Mammals are the only vertebrates in which the embryo develops internally! |
Chondrichthyes
(Cartilaginous Fish) | Skeleton is made of cartilage instead of bone
Have 5-7 gill slits but lack gill covers
Ex. Rays, skates, sharks |
Osteichthyes
(Bony Fish) | Most numerous of the vertebrates.
Skeletons are made of bone.
Ex. Herring, trout, cod |
Amphibia
(Amphibians) | In early stages are gill breathers in water, but live as air breathing adults on land.
Have a heart with 3 chambers.
Ex. Frogs, toads |
Reptilia
(Reptiles) | Have better developed lungs than amphibians.
Have a rib cage
Skin is thick and scaly & is made from keratin (a protein)
They shed their skin several times each year.
Ex. Lizards & snakes |
Aves
(Birds) | Have feathers
Bones are hallow…..why??
Ex. Robins, Blue Jays, Swallows |
Mammalia
(Mammals) | Have hair
Have milk-producing mammary glands
Give birth to live young
Most live on land
A small number are adapted to life in the water (i.e. whales, dolphins) |