Invertebrates

1. Invertebrates Chapter 15 Table of Contents Section 1 Simple Invertebrates Section 2 Mollusks and Annelid Worms Section 3 Arthropods Section 4 Echinoderms

2. Chapter 15 Section 1 Simple Invertebrates Bellringer • Record your answers to the following questions in yourscience journal: • What is an invertebrate? • What is your favorite invertebrate? • What special features help your favorite invertebrate survive?

3. Chapter 15 Section 1 Simple Invertebrates Objectives • Describe the body plans, nervous systems, and guts of invertebrates. • Explain how sponges get food. • Describe three cnidarian characteristics. • Describe the three kinds of flatworms. • Describe the body of a roundworm.

4. Chapter 15 Section 1 Simple Invertebrates Invertebrate Characteristics • An Invertebrateis an animal that does not have a backbone. • About 96% of all animal species are invertebrates • Invertebrates have three basic body plans, or types of symmetry: bilateral, radial, or asymmetrical.

5. Chapter 15 Section 1 Simple Invertebrates

6. Chapter 15 Section 1 Simple Invertebrates Invertebrate Characteristics, continued • Nerves = allow animals to sense their environment and control their actions. • All animals except sponges have nerves. • Nerve cord = packs of neurons that carry messages along a single nerve • Ganglion is a concentrated mass of nerve cells. • Each ganglion controls different body parts • In complex invertebrates ganglion are controlled by a brain.

7. Chapter 15 Section 1 Simple Invertebrates Invertebrate Characteristics, continued • Guts • Almost all animals digest food in a gut. • A gut is a pouch lined with cells that release chemicals that break down food into small particles. • In complex organisms the gut is inside a coelom. • coelomis a body cavity that surrounds the gut.

8. Chapter 15 Section 1 Simple Invertebrates Sponges • simplest invertebrates. • are asymmetrical and have no tissues, gut, or nerves.

9. Eating Pores are the holes on the outside of the sponge’s body that lets water into the sponge. Collar cells – line the central cavity and filter and digest food from the water that enters the body. osculum = the hole at the top that water leaves through. Sponges, continued

10. Chapter 15 Section 1 Simple Invertebrates

11. Chapter 15 Section 1 Simple Invertebrates Sponges, continued • Body Part Abilities • Sponges are the only animals that can use regeneration as a form of reproduction. • Regenerate – broken body parts grow back • fragments can grow into a new sponge • Spicules – hard fibers that form a skeleton

12. Chapter 15 Section 1 Simple Invertebrates Cnidarians • more complex than sponges • have complex tissues, a gut, and a simple nerve network, regeneration. • Two Body Forms • Medusas swim through the water. • Polyps usually attach to a surface. • Both the medusa and the polyp forms have radial symmetry.

13. Chapter 15 Section 1 Simple Invertebrates Body Form of Cnidarians

14. Chapter 15 Section 1 Simple Invertebrates Cnidarians • Stinging Cells • All cnidarians have tentacles covered with stinging cells • Poisonous spear is triggered by hair like trigger • used to protect themselves and to catch food.

15. Kinds of Cnidarians There are three major classes of cnidarians: hydrozoans - live in fresh & ocean water. Most spend life as polyps jellyfish – spend most of their live as medusa & catch fish & other invertebrates on tentacles sea anemones & corals - mostly brightly colored polyps

16. corals – live in colonies made of calcium carbonate Each new colony builds on top of the last generation building huge coral reefs over thousands of years. In danger because of over fishing, pollution, mining, coral harvesting, coastal development, swimmers and boaters. Don’t touch the coral!.

17. Chapter 15 Section 1 Simple Invertebrates Flatworms • Flat worms have bilateral symmetry • a clearly defined head • two large eyespots that sense the direction that light is coming from. • sensory lobes that are used for detecting food.

18. Chapter 15 Section 1 Simple Invertebrates Flatworms, continued • Planarians • live in freshwater lakes and streams or on land in damp places. • are predators. • Digest food in a gut • Have well developed nervous system

19. Flukes are parasites. Fertilized eggs pass with waste out of host and infect water or food Suckers or hooks that attach to host Tiny heads with no eyespots or sense organs Flatworms, continued

20. Chapter 15 Section 1 Simple Invertebrates Flatworms, continued • Tapeworms • Parasite that live in the intestine of animals • have a small head with no eyespots, gut, sensory lobes. • attach to the host’s intestines and absorb nutrients. • eggs contaminate food, water, or other surfaces

21. Chapter 15 Section 1 Simple Invertebrates Roundworms • Roundworms have bodies that are long, slim, and round, like spaghetti. • have bilateral symmetry. • simple nervous system • ring of ganglia that forms a simple brain. • Parallel nerve cords connect the two ends of their body.

22. Some round worms eat dead tissue and are good decomposers Many roundworms are parasites such as pinworms, & hookworms that infect humans. Trichinella from under cooked pork