1. Introduction to AnimalsSection 2 CH 26:Introduction to Animals Sec 1 and Sec 2

2. Introduction to AnimalsSection 2 General Features of Animals Animals are multicellular, heterotrophic organisms with cells that lack cell walls. Humans depend on other animals for food, companionship, and to pollinate crops. Most animals move to get food. But filter eaters, such as sponges and corals, catch particles of food that drift by in the water.

3. Introduction to AnimalsSection 2 Kinds of Animals Animals are often grouped as invertebrates or vertebrates. Vertebrates make up only a subgroup of one phylum— Chordata. Most animals are invertebrates.

4. Introduction to AnimalsSection 2 Kinds of Animals, continued Vertebrates Vertebrates have a cranium and an internal skeleton composed of bone or cartilage. Vertebrates are chordates that have a backbone. The backbone supports and protects a dorsal nerve cord and provides a site for muscle attachment. Pg 625

5. Introduction to AnimalsSection 2 CH26 Sec 2: Animal Body Systems

6. Introduction to AnimalsSection 2 Key Ideas Why is an animal's skeleton important? What are the functions of the digestive and excretory systems? What is the function of the nervous system? Why are the respiratory and circulatory systems important? What are two reproductive strategies of animals?

7. Introduction to AnimalsSection 2 Support An animal's skeleton provides support for the animal's body and location for muscle attachment. Many soft-bodied invertebrates, such as jellyfish, have a hydrostatic skeleton –which is a water-filled cavity that is under pressure. An exoskeleton is a rigid external skeleton that encases the body of an animal. An endoskeleton is an internal skeleton made of bone and cartilage.

8. Introduction to AnimalsSection 2 Digestive and Excretory Systems The digestive system is responsible for extracting energy and nutrients from an animal's food. The excretory system removes waste products from the animal's body.

9. Introduction to AnimalsSection 2 Digestive System A gastrovascular cavity is a digestive cavity with only one cavity. The hydra has a gastrovascular cavity.

10. Introduction to AnimalsSection 2 Digestive System, continued In a digestive tract, food moves from one opening, the mouth, to a second, the anus. Digestive tracts allow for specialization and more efficient digestion.

11. Introduction to AnimalsSection 2 Digestive and Excretory Systems, continued Excretory System The removal of wastes produced by cellular metabolism. Simple aquatic invertebrates and some fishes excrete ammonia through their skin or gills. Terrestrial animals need to minimize water loss.

12. Introduction to AnimalsSection 2 Nervous System Carries information about the environment through the body and coordinates responses and behaviors. –Nerve net –Ganglia –Brain

13. Introduction to AnimalsSection 2 Hydra Nervous System

14. Introduction to AnimalsSection 2 Flatworm Nervous System

15. Introduction to AnimalsSection 2 Grasshopper Nervous System

16. Introduction to AnimalsSection 2 Respiratory and Circulatory Systems The respiratory system is responsible for exchanging oxygen and carbon dioxide between the body and the environment. –Gills –Lungs The circulatory system transports gases, nutrients, and other substances within the body.

17. Introduction to AnimalsSection 2 Circulatory System Open circulatory system –a heart pumps fluid containing oxygen and nutrients through vessels into the body cavity. –The fluid provides oxygen and nutrients as it washes across the tissues. Closed circulatory system –the blood is pumped through the body within vessels –is never in direct contact with the body's tissues.

18. Introduction to AnimalsSection 2 Open and Closed Circulatory Systems

19. Introduction to AnimalsSection 2 Reproduction Asexual reproduction occurs when an individual produces exact copies of itself and gametes are not exchanged. –Budding –Parthenogenesis –Fragmentation Sexual reproduction, a new individual is formed by the union of a male and female gametes. Some species can reproduce either asexually or sexually.