Name
Date
Class
Notes: 393-398
LESSON 11-3
Phylum Chordata
A. Characteristics of Vertebrates
1. All vertebrates have a(n) backbone, also called a spinal column or spine.
2. Bones that form a backbone are called vertebrae.
3. All vertebrates have digestive systems with 2 openings, circulatory systems that move blood through
the body, and nervous systems that include brains.
Coldblooded Vertebrates (Ectotherms)
B. Fish
1. Fish have two important characteristics in common: gills that absorb oxygen gas from water and paired
fins that aid in swimming.
2. Hagfish and lampreys lack jaws and are in a group called _jawless_ fish.
3. Sharks, skates, and rays are cartilaginous fish.
4. Jawless and cartilaginous fish have internal structures made of cartilage.
5. Trout, guppies, perch, tuna, mackerel, and thousands of other species have bones and are grouped
together as bony fish.
C. Amphibians (“Double Life”)
1. Frogs, toads, and salamanders belong to the class Amphibia.
2. Young amphibians (tadpoles) live in water and have gills and fins. Through _metamorphosis, most
adults develop lungs and _limbs_ and live on land, but remain near water.
3. Amphibians lay _eggs_ in _water. These eggs do not have hard protective coverings, or _shell.
4. Amphibians have _smooth skin and can take oxygen and water directly through their skin.
D. Reptiles
1. Lizards, snakes_, turtles, crocodiles, and alligators belong to the class Reptilia.
2. All reptiles have waterproof skin that is covered in scales.
3. Like amphibians, most reptiles have three-chambered hearts.
4. Unlike amphibians, lizards and other reptiles have lungs throughout their lives.
5. Most reptiles lay fluid-filled eggs with leathery shells.
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