Grouping of Animals

Science, Grade 3

adult immature frog tadpoles eggs Amphibian Life Cycle Animals can be classified, or grouped together, by the things they have in common, like by how they act, where they live, or how they look. Many scientists separate animals into two main groups, those animals that have a backbone from those that do not have a backbone. These two groups are called vertebrates and invertebrates. Vertebrates are animals that have a backbone. There are five main groups of vertebrates based on specific animal traits and characteristics. Those groups include fish, birds, reptiles, amphibians, and mammals. Fish are vertebrates that live their whole life in water. Fish breathe oxygen through their gills and have scales on their bodies. Birds are vertebrates that have feathers, wings, and a beak. Most birds can fly. Birds breathe oxygen through their lungs. Mammals are vertebrates that have hair, breathe through their lungs, and make milk to feed their young. Reptiles are also a group of invertebrates. Snakes, crocodiles, and turtles are all examples of reptiles. Reptiles have tough skin with scales, most reptiles lay eggs. Sea jellies are a type of invertebrate. Sea jellies have soft bodies, live in the ocean, and parts of their body can sting. Jellyfish are examples of sea jellies. Arthropods’ skeletons are on the outside of their bodies. Their bodies are made up of several parts and sections. Insects, crabs, and spiders are all examples of arthropods. Worms are invertebrates that have long, soft bodies and no legs. There are flat worms, round worms, and segmented worms. Worms live in many different places, including the ocean! Mollusks are invertebrates that have soft bodies. Many mollusks have shells to protect and support their soft bodies. An example of a mollusk is a snail. Amphibians are another group of vertebrates which include frogs and toads. Amphibians live in water and on land. Most amphibians start off breathing through their gills in water. As an amphibian grows and begins to live on land, it develops lungs to breathe with. Invertebrates are animals that do not have a backbone. Most animals living in the world today are invertebrates. Most kinds of invertebrates are insects. Invertebrates have liquid sacs or shells that they use as support for their bodies. There are four major kinds of invertebrates, which include sea jellies, arthropods, worms, and mollusks. scales gills jellyfish snail beetle worms hermit crab anemone clam Grouping of Animals backbone © Copyright NewPath Learning. All Rights Reserved. 94-4304
Amphibian Life Cycle Key Vocabulary Terms amphibians lungs arthropods mammals backbone mollusks birds reptiles fish sea jellies gills vertebrates insect worms invertebrates How are animals grouped or classified? ____________________________ ______________________________________________________________ What are the two main groups of animals? __________________________ ______________________________________________________________ Describe a vertebrate animal. _____________________________________ ______________________________________________________________ Describe the five groups of vertebrate animals: Describe an invertebrate animal. _____________________________________________ _________________________________________________________________________ Describe the four major kinds of invertebrates: Sea jellies ________________________________________________ _________________________________________________________ . Arthropods _______________________________________________ _________________________________________________________ . Worms ___________________________________________________ _________________________________________________________ . Mollusks _______________________________________ ______________________________________________ . Fish ___________________________ _______________________________. Reptiles _______________________ _______________________________. Birds __________________________ _______________________________. Mammals ______________________ _______________________________. Amphibians ____________________ _______________________________ _______________________________ _______________________________ _______________________________. Grouping of Animals © Copyright NewPath Learning. All Rights Reserved. 94-4304 \|xiBAHBDy01716lz[