Interest Grabber Section 28 1 Hard on the

Interest Grabber Section 28 -1 Hard on the Outside but Soft on the Inside Some animals, such as humans, are soft on the outside but have endoskeletons. Other animals, such as insects and spiders, have exoskeletons. If you’ve ever had to wear a cast while a broken bone healed, you have some idea of what an exoskeleton is like. Imagine that you have a cast on your thumb. 1. 2. 3. 4. List two ways that a cast can protect your thumb and your skin cannot. What functions might an exoskeleton have for insects and spiders? How would a cast on your thumb affect the way you use your hand? Do you think an exoskeleton has the same limitations? Explain your answer.

Section Outline Section 28 -1 28– 1 Introduction to the Arthropods A. What Is an Arthropod? B. Evolution of Arthropods C. Form and Function in Arthropods 1. Feeding 2. Respiration 3. Circulation 4. Excretion 5. Response 6. Movement 7. Reproduction D. Growth and Development in Arthropods

Concept Map Section 28 -1 Anthropods feed on respire using All types of foods Tracheal tubes reproduce using Internal fertilization Book lungs have well-developed External fertilization Book gills Heart Brain Muscles

Figure 28– 4 The Anatomy of a Grasshopper Section 28 -1 Compound eye Brain Antennae Digestive tract Malpighian tubules Heart Reproductive organs Ventral View Legs Mouth Salivary glands Anus Ganglia Tracheal tubes Spiracles Nerve cord Tracheal tubes Spiracles

Interest Grabber Section 28 -2 Form Fits Function to Snag a Speeding Insect You probably know that spiders spin webs. And you may have seen a spider lowering itself by a single slender thread. But did you know that spiders make as many as seven different types of silk threads? 1. For what functions might spiders spin silk threads? 2. The type of spider silk used in the center of webs is called capture silk. It is very stretchy. Why might stretchy silk fit this function well? 3. The type of silk spiders use to lower themselves is called dragline silk. It is not very stretchy. Why might less-stretchy silk fit this function well? Arial

Section Outline Section 28 -2 28– 2 Groups of Arthropods A. Crustaceans B. Spiders and Their Relatives 1. Horseshoe Crabs 2. Spiders 3. Mites and Ticks 4. Scorpions C. Insects and Their Relatives 1. Centipedes 2. Millipedes

The Anatomy of a Crayfish Section 28 -2 Tail Abdomen Cephalothorax Swimmerets Carapace First antenna Mandible Walking legs Second antenna Cheliped

Figure 28– 9 The Anatomy of a Spider Section 28 -2 Cephalothorax Brain Abdomen Pumping stomach Heart Intestine Ovary Malpighian tubules Eyes Poison gland Anus Pedipalp Fanglike chelicera Spiracle Bases of walking legs Airflow Book Lung Spinnerets Silk glands

Interest Grabber Section 28 -3 What’s in a Name? Like all arthropods, insects have segmented bodies, tough exoskeletons, and jointed appendages. What makes them different from other arthropods is that insects have bodies divided into three parts—head, thorax, and abdomen. They also have three pairs of legs attached to their thoraxes.

Interest Grabber continued Section 28 -3 Working in a group, each group member should perform the following activity. 1. On a sheet of paper, make a sketch of an insect that you have seen around school or at home. Below your drawing, list those features that allow the insect to be successful in its habitat. 2. What features does the insect have that help it survive? 3. How many features did your group’s insects have in common? What were these features? 4. Describe the positive and negative impacts that these features have on humans. 5. What is meant by the statement, “Of all the animals, insects have had the greatest impact on the activities of this planet”?

Section Outline Section 28 -3 28– 3 Insects A. What Is an Insect? 1. Responses to Stimuli 2. Adaptations for Feeding 3. Movement and Flight 4. Metamorphosis B. Insects and Humans C. Insect Communication D. Insect Societies 1. Castes 2. Communication in Societies

Insect Diversity Section 28 -3 Noninsect arthropods (12%) Nonarthropod invertebrates (11%) Vertebrates (4%) Insects (73%)

Figure 28– 18 Metamorphosis Section 28 -3 Adult Eggs Incomplete Metamorphosis Complete Metamorphosis Larva Adult Nymph Immature Nymph Adult Larva Pupa

Interest Grabber Section 28 -4 If You Were a Two-Sided Animal. . . Imagine that you were an animal like no other in the animal kingdom. You have no head and no tail. However, you have two sides, with your toothless mouth on one side. You have no arms or legs, and your body is shaped like a disc. 1. Briefly describe the type of environment in which you would be most likely to survive. Why do you think you would live in this type of environment? 2. What types of food would you likely eat? Explain your answer. 3. What species name would you give yourself?

Section Outline Section 28 -4 28– 4 Echinoderms A. What Is an Echinoderm? B. Form and Function in Echinoderms 1. Feeding 2. Respiration and Circulation 3. Excretion 4. Response 5. Movement 6. Reproduction C. Groups of Echinoderms 1. Sea Urchins and Sand Dollars 2. Brittle Stars 3. Sea Cucumbers 4. Sea Stars 5. Sea Lilies and Feather Stars D. Ecology of Echinoderms

Compare/Contrast Table Section 28 -4 Comparing Groups and Major Characteristics of Echinoderms Characteristic Sea urchins and sand dollars Brittle stars Sea cucumbers Sea stars Sea lilies and feather stars Feeding Detritivores Most carnivores Herbivores Shape Disc- or globeshaped, no arms Star-shaped, arms Cucumbershaped, no arms Star-shaped, arms Stalk with feathery arms Movement Burrow in sandy ocean bottom or wedge in rock crevices using moveable spines attached to endoskeleton Move rapidly along ocean floor using arms Move slowly along ocean floor using muscular body wall to crawl Creep slowly along ocean floor using arms Cannot move; attached to ocean bottom

Figure 28– 23 The Anatomy of a Starfish Section 28 -4 Eyespot Endoskeletal plates Anus Stomach Digestive glands Ring canal Radial canal Madreporite Reproductive glands Tube foot Sucker