1. Animals

2. 1.Animals are all heterotrophs, meaning that they obtain nutrients and energy by feeding on organic compounds from other organisms.

3. 2. Animals are multicellular, or composed of many cells.

4. 3. The cells that make up animal bodies are eukaryotic, meaning that they contain a nucleus and membrane- bound organelles. 4. No. Animal cells do not have cell walls.

5. 5. The bodies of most animals contain tissues. The four main types of tissue are:

6. 6. Epithelial tissues cover body surfaces.

7. 7. Muscle tissue contains proteins that enable the cells to contract, moving parts of the animals’ bodies.

8. 8. Connective tissue supports an animal’s body and connects its parts. Two examples are bone and blood.

9. 9. Nervous tissue is composed of nerve cells. Nervous tissue carries information throughout the body.

10. 10. Over 95% of all animal species are often grouped in a single, informal category: invertebrates.

11. 11. Invertebrates are animals that have no backbone, or vertebral column.

12. 12. Vertebrates are animals with a backbone.

13. 13. The 5 groups of vertebrates are: fishes, amphibians, reptiles, birds, and mammals.

14. 14. Animals carry out the following essential functions: feeding, respiration, circulation, excretion, response, movement, and reproduction.

15. 15. Physiology is the study of the functions of organisms.

16. 16. Anatomy is the structure of an animal’s body.

17. 17. Homeostasis is a process through which animals maintain a stable internal environment.

18. 18. Homeostasis is often maintained by internal feedback mechanisms. Feedback inhibition occurs when the product or result of a process stops or limits the process.

19. 19. Most animals cannot absorb food. Instead, they ingest (or eat) it. 20. HerbivoresCarnivoresOmnivoresDetritivoresFilter Feeders Eat plantsEat other animals Feed on both plants and animals Feed on decaying plant and animal material Strain tiny floating organisms from water

20. 21. Symbiosis is a relationship in which two species live in close association with each other.

21. 22.All animals respire, which means that they take in oxygen and give off carbon dioxide. 23. Most complex animals have evolved complex tissues and organ systems for respiration.

22. 24. Large animals require a circulatory system to move materials around within their bodies.

23. 25. A primary waste product of cells is a poisonous substance called ammonia. A buildup of ammonia would kill an animal. 26. Most animals have an excretory system that either eliminates ammonia quickly or converts it into a less toxic substance.