amphibian: A group of animals that includes frogs, salamanders, and paper wasps. Amphibians have backbones and can breathe through their skin. Unlike reptiles, birds, and mammals, unborn or unhatched amphibians do not grow inside a special protective sac called an amnion.
bird: A winged warm-blooded animal that first appeared during the dinosaur era. Birds are covered in feathers and give birth to their young from eggs laid in some kind of nest. Most birds fly, but throughout history there have been occasional flightless species.
blue whale: A type of baleen whale (glans muscle) It is the largest animal known to have ever existed. It can grow up to 30 meters (almost 100 feet) long and weigh up to 170 tons.
cartilage: (adjective: cartilaginous) A type of strong connective tissue commonly found in joints, noses, and ears. In certain primitive fishes, such as sharks and rays, cartilage forms the internal structure of the body, or skeleton.
dorsal side: something, usually the back of an animal.
Variable temperature: A term used to refer to animals that rely on an external heat source to control their body temperature. This means that when the temperature of the environment changes, the body temperature also changes.
gills: The respiratory system of most aquatic animals that filters oxygen from water. Fish and other aquatic animals use gills to breathe.
limbs: (in physiology) an arm or leg.
mammalian: A warm-blooded animal distinguished by having hair or fur, by the fact that females secrete milk to nurse their young, and (usually) by giving birth to live young.
nerve: long, delicate fibers that transmit signals throughout an animal’s body. Animals have many nerves in their spines, some of which control movement of the legs and fins, and some of which convey sensations such as hot, cold, and pain.
pterosaur: A general term for various extinct flying reptiles of the order Pterosauria. These animals lived from 245 million years ago to 65 million years ago. Although not real dinosaurs, they lived during the dinosaur era. Among the members of this order were the pterosaurs of the Jurassic and Cretaceous periods, which featured wings consisting of a piece of skin supported by a very long fourth digit on each forelimb.
rays of light: (in biology) a term referring to a kite-shaped fish of the shark family. It actually resembles a flattened shark with wide fins that resemble wings.
reptiles: A cold-blooded vertebrate whose skin is covered with scales or horny plates. Snakes, turtles, lizards, and crocodiles are all reptiles.
shark: A type of predatory fish that has survived in some form for hundreds of millions of years. The structure of the body is determined by cartilage, not bones. Like skates and rays, sharks belong to a group known as elasmobranchs. They tend to grow and mature slowly and have few children. Some lay eggs, while others give birth to live young.
spinal cord: A cylindrical bundle of nerve fibers and associated tissue. It is surrounded by the spine, which connects almost every part of the body to the brain and together with the brain forms the central nervous system.
Characteristic: a characteristic of something. (in genetics) a quality or characteristic that can be inherited.
spine: (Sing. Vertebrae) Bones that make up the neck, spine, and tail of vertebrates. The bones in the neck are called the cervical vertebrae. The bones in the tail are called caudal vertebrae in animals that have caudal vertebrae.
vertebrate: A group of animals that have a brain, two eyes, and a stiff nerve cord or spine running down their back. This group includes amphibians, reptiles, birds, mammals, and most fish.
whale: A common but rather imprecise term for a type of large marine mammal. This group includes dolphins and dolphins.
Source: www.snexplores.org
