Vertebrate Notes
What is a Vertebrate?
A. Characteristics of chordates:
1. At some time in their lives, chordates will have a notochord, a nerve chord that runs down their back and slits in their throat.
a. Notochord: a flexible rod that supports a chordate’s back.
b. Nerve Chord in back: spinal chord
c. Slits in throat area: pharyngeal slits or gill slits.
d. closed circulatory system
B. Characteristics of Vertebrates: a backbone that is part of an internal skeleton.
1. The backbone is formed by many similar bones called vertebrae. The vertebrae are lined up like bead on a string.
2. Internal skeleton:
a. endoskeleton: protests the internal organs of the body.
Does not need to be replaced as the animal growsn.
Supports against pull of gravity.
Allows vertebrates to be bigger than animals with exoskeletons or no skeleton at all.
C. Keeping conditions stable.
1. Ectotherm: an animals that is dependent on its surroundings for body heat
fish, amphibians, and reptiles
2. Endotherm: An animal that regulates its own body heat.
Birds and mammals
Types of Vertebrates
A. Characteristics of Fishes
• Lives in water
•Uses fins to move
•ectotherms
• obstain oxygen through gills
• scales
•Most have external fertilization of eggs. Sharks and guppies have internal fertilization.
1. Three types of fish:
a. jawless: no jaws and no scales
ex: catfish and lampreys
b. bony: jaws, scales, pocket on each side of head to hold gills, and bones.
Ex: trout, tuna, goldfish
c. Cartilaginous: jaws, scales and cartilage skeleton.
Ex: Sharks and rays.
B. Characteristics of Amphibians
Groups: frogs, toads, salamanders
•Ectothermic
•Spends early life in water.
• Amphibian: double life
•Most spend adult life on land and return to water to reproduce.
•Gills in water lungs on land.
C. Characteristics of Reptiles
•Ectotherm
•Use Lungs to breath
•Thick, tough, scaly skin.
•Skin, kidneys, and eggs of reptiles are adapted to conserve water.
•Amniotic eggs
D. Characteristics of Birds
•Endothermic
•Feathers
•Four chambered heart.
•Lays amniotic eggs
•Light hollow bones allow adaptations for flight.
E. Characteristics of Mammals
•Endothermic
•Four chambered heart
•Skin with fur or hair.
•Born alive
•Young are fed with milk form the mother’s mammary glands.
Obtaining food:
1. herbivore: eats plants
2. carnivore: eats other animals
3. omnivore: eats plants and animals
Types of mammals
1. Monotremes: Egg laying mammals
spiny anteater and duck-billed platypus
2. Marsupials: Young born at an early stage of development and they develop in the pouch of the mother.
Ex: Kangaroos and oppossums
3. Placental: develops inside the mother until the baby’s body can function independently.
Ex: Humans, dogs, cats etc….