Chondrichthyes Class Chondricthyes includes animals that have large jaws; cartilaginous endoskeleton; rough skin due to tiny plates (denticles) in the skin; breath through gills; internal fertilization and embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic

Osteichthyes Class Osteichthyes includes animals that have jaws; bony endoskeleton; skin covered with scales; breath through gills; external fertilization and embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic

Amphibia Class Amphibia includes animals that are ectothermic (body temperature changes with the environmental temperature); aquatic larval stage undergoes metamorphosis to form adult form adapted to terrestrial habitat; external fertilization and embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic

Reptilia Class Reptilia includes animals that are ectothermic; skin has hard keratinized scales; may or may not have appendages; Internal fertilization; egg protected by a shell for external embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic

Aves Class Aves includes animals that are endothermic (maintain internal body temperature irrespective of environmental temperature); body is covered with feathers; forelimbs are modified to form wings adapted to flying; internal fertilization; shell protected egg to support external embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic

Mammilia Class Mammalia includes animals that are endothermic; possess mammary glnads to nourish newborn; skin is covered with hair or fur; internal fertilization and embryo development Includes animals that have the brain and the nerve cord protected inside a vertebral column; endoskeleton mey be bony or cartilaginous; blood circulates inside a circulatory system; fertilization and embryo development can be external or internal Includes animals that have a notochord that supports the embryo; notochord is replaced by a bony or a cartilagenous vertebral column in most animals Includes animals that are bilaterally symmetrical, have triploblastic (three layered) embryo, and exhibit different levels of cephalization Includes animals that are symmetrical and have tissue differentiation Animals are eukaryotic, multicellular and heterotrophic