Introduction to Animals

Learn about animals! Classify, understand symmetry, and more.

Read each sentence below and fill in the blank with the correct word that best completes the statement. Use your notes and page 308 to 333 in your textbook. 1. All animals are multicellular organisms that feed on other organisms and perform the same basic functions.2. The main functions of an animal are to obtain food and oxygen, keep internal conditions stable, move in some way and reproduce.3. Keeping internal body conditions stable is called homeostasis.4. Structures and behaviors that allow animals to perform their functions are called adaptations.5. Animals are classified according to how closely they are related to other animals. These relationships are determined by an animal’s structure, the way the animal develops and its DNA.6. All animals are either vertebrates or invertebrates.7. Vertebrates are animals with a backbone . Invertebrates are an animal without a backbone.8. All animals are made up of many cells. A tissue is a group of similar cells that perform a specific function.9. An organ is made up of different tissues. Groups of organs make up organ system.10. An animal has radial symmetry if many imaginary lines can be drawn through a central point to divide it into mirror images.11. An animal has bilateral symmetry if only one line of symmetry can be drawn to divide it into halves that are mirror images.12. The bodies of animals without symmetry are organized simply, with some specialized cells but no tissues.13. All animals with radial symmetry live in water.14. In general, animals with bilateral symmetry are larger and more complex than animals with radial symmetry.15. Most animals with bilateral symmetry have a head at their front ends. Most of an animal’s specialized sense organs are in its head.16. Sponges are asymmetrical invertebrates.17. Jellyfish and corals are examples of cnidarians invertebrates that have stinging cells and take food into a central cavity.18. The three phyla of worms are flatworms, roundworms and segmented worms.19. All mollusks have a thin layer of tissue called a mantle that covers their internal organs and an organ called a foot.20. Arthropods are invertebrates that have hard outer coverings, segmented bodies and pairs of jointed appendages.21. An echinoderm is an invertebrate with an internal skeleton and system of fluid filled tubes. Examples are sea stars and sea urchins.22. An internal skeleton is an endoskeleton.23. At some point in their lives, all chordates have three characteristics: a notochord, a nerve cord and pouches in the throat area.24. The backbone or spine, runs down the center of the back and replaces the notochord.25. The backbone is made up of a stack of many small bones called vertebrae.26. An endoskeleton shapes and supports the body. It protects organs and gives muscles to a place to attach.27. An animal that produces little internal heat is called ectotherm. It’s body temperature changes with the environment. Amphibians, reptiles and most fish are ectotherms.28. An endotherm is an animal that controls the internal heat it produces and regulates its own temperature. Birds and mammals are endotherms.29. There are five major groups of vertebrates. They are fishes, amphibians, reptiles, birds and mammals.30. Some fishes have skeletons made of cartilage, a tissue more flexible than bone.31. Amphibian means double life. Most amphibians spend their adult life on land. They return to water to lay eggs and reproduce. 32. A reptile is an ectothermic vertebrate that has scaly skin and lays eggs on land.33. A bird is an endothermic vertebrate that lays eggs and has feathers and four chambered heart.34. Mammals are endothermic vertebrates that have skin covered with fur or hair and have a four chambered heart.35. Mammal groups differ in how their young develop. Monotremes lay eggs.36. Marsupials are born at an early stage of development, and they usually continue development in a pouch on their mother’s body.37. A placental mammal develops inside its mother’s body until its body system can function independently.