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2. Resources Chapter Presentation Visual Concepts Transparencies Standardized Test Prep

3. Chapter 36 Arthropods Table of Contents Section 1 Phylum Arthropoda Section 2 Subphylum Crustacea Section 3 Subphylum Chelicerata and Myriapoda

4. Section 1 Phylum Arthropoda Chapter 36 Objectives • Describethe distinguishing characteristics of arthropods. • Explainthe process of molting in an arthropod. • Listthe five major subphyla of the phylum Arthropoda.

5. Section 1 Phylum Arthropoda Chapter 36 Characteristics of Arthropods • The members of the phylum Arthropoda are called arthropods. • Arthropods are segmented animals with body segments that bear appendages. • Arthropods have an exoskeleton that provides protection and support and contains chitin. • Arthropods show a high degree of cephalization. Most have segmented antennae and compound eyes.

6. Section 1 Phylum Arthropoda Chapter 36 Segmentation

7. Section 1 Phylum Arthropoda Chapter 36 Compound Eye

8. Section 1 Phylum Arthropoda Chapter 36 Function of the Compound Eye

9. Section 1 Phylum Arthropoda Chapter 36 Characteristics of Arthropods, continued Molting • The rigid exoskeleton limits the size to which an arthropod can grow. • So, each arthropod periodically sheds its exoskeleton and makes a new one in the process of molting. • An anthropod goes through many cycles of molting during its life.

10. Section 1 Phylum Arthropoda Chapter 36 Characteristics of Arthropods

11. Section 1 Phylum Arthropoda Chapter 36 Characteristics of Arthropods

12. Section 1 Phylum Arthropoda Chapter 36 Arthropod Exoskeleton

13. Section 1 Phylum Arthropoda Chapter 36 Evolution and Classification • Arthropods likely evolved from a common ancestor that lived about 545 million years ago. • However, biologists are still uncertain about much of arthropod phylogeny. • The similar characteristics of many modern subgroups of arthropods may be the result of convergent evolution.

14. Section 1 Phylum Arthropoda Chapter 36 Evolution and Classification, continued • Many ancient and extinct arthropods, such as trilobites, had many body segments and one pair of appendages on each segment. • Most living arthropod species have some segments that lack appendages and some segments that are fused into a larger structure called a tagma (plural, tagmata).

15. Section 1 Phylum Arthropoda Chapter 36 Evolution and Classification, continued • Arthropods are usually divided into five subphyla on the basis of differences in development and in the structure of appendages, such as mouthparts. • The two major types of mouthparts are: • mandibles, which are jawlike • chelicerae (singular, chelicera), which are pincerlike • The five main subphyla are: • Trilobita • Crustacea • Chelicerata • Myriapoda • Hexapoda

16. Section 1 Phylum Arthropoda Chapter 36 Phylogenetic Diagram of Arthropods

17. Section 1 Phylum Arthropoda Chapter 36 Types of Arthropods

18. Section 2 Subphylum Crustacea Chapter 36 Objectives • Describethe characteristics of crustaceans. • Compareaquatic crustaceans with terrestrial crustaceans. • Explainthe functions of the appendages on a crayfish. • Summarizedigestion, respiration, circulation, excretion, and neural control in crayfish.

19. Section 2 Subphylum Crustacea Chapter 36 Characteristics • The subphylum Crustacea contains about 38,000 known species. • Crustaceans are so diverse that their single defining characteristic is having two pairs of antennae. • Most crustaceans also have: • a pair of mandibles • a pair of appendages on each body segment • some branched appendages • 16 to 20 segments and several tagmata

20. Section 2 Subphylum Crustacea Chapter 36 Characteristics, continued Some crustaceans respire through their exoskeleton, others respire through gills. • Many have a free-swimming larval stage called a nauplius.

21. Section 2 Subphylum Crustacea Chapter 36 Anatomy of a Nauplius

22. Section 2 Subphylum Crustacea Chapter 36 Diversity of Crustaceans Aquatic Crustaceans • Copepods are abundant in marine environments and an important part of the ocean’s plankton. • In freshwater environments, much of the plankton is composed of water fleas such as Daphnia species. • Barnacles are sessile as adults. • Free-swimming barnacle larvae attach themselves to marine surfaces and develop a shell that encloses the body. • Barnacles use their cirri (singular, cirrus) to sweep food from the water into their mouths.

23. Section 2 Subphylum Crustacea Chapter 36 Diversity of Crustaceans, continued Terrestrial Crustaceans • Sow bugs and pill bugs are terrestrial isopods. • They lack adaptations for conserving water and live only in moist environments. • They generally feed on decaying vegetation. • Pill bugs roll into a ball when disturbed or threatened.

24. Section 2 Subphylum Crustacea Chapter 36 The Crayfish • The crayfish is an abundant freshwater crustacean that is structurally similar to lobsters, which are marine crustaceans. • Crayfish, lobsters, crabs, and shrimp are decapods, or members of the order Decapoda. Decapoda means “10 feet.” • Decapods have five pairs of legs that are used for locomotion.

25. Section 2 Subphylum Crustacea Chapter 36 The Crayfish, continued External Structure • The crayfish’s body is divided into • the cephalothorax, which is covered by the carapace and is divided into • the head, which has five segments • the thorax, which has eight segments • the abdomen, which is is divided into six segments

26. Section 2 Subphylum Crustacea Chapter 36 The Crayfish, continued External Structure, continued • A pair of appendages is attached to each segment of the crayfish. Several pairs have specialized functions. • These appendages include: • Antennae • Antennules • Mandibles • Maxillae • Maxillipeds • Chelipeds • Walking legs • Swimmerets

27. Section 2 Subphylum Crustacea Chapter 36 External Anatomy of a Crayfish

28. Section 2 Subphylum Crustacea Chapter 36 The Crayfish, continued Digestion • Crayfish have a digestive gland that is near the stomach and that secretes enzymes for digestion. Respiration • Walking circulates water across the gills. Circulation • The circulatory system is open.

29. Section 2 Subphylum Crustacea Chapter 36 The Crayfish, continued Excretion • Green glands assist in excretion of excess water that enters the body by osmosis. Neural Control • The nervous system of the crayfish is typical of arthropods and is similar to that of annelids. Sensory Organs • Crayfish sense vibrations and chemicals in the water with thousands of small sensory hairs. • Their compound eyes are set on two stalks.

30. Section 2 Subphylum Crustacea Chapter 36 Internal Anatomy of a Crayfish

31. Section 2 Subphylum Crustacea Chapter 36 Anatomy of a Crayfish

32. Section 2 Subphylum Crustacea Chapter 36 Characteristics of Crustaceans

33. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Objectives • Listthe characteristics of arachnids, as represented by a spider. • Explainthe adaptations that spiders have for a predatory life on land. • Identifythe unique characteristics of scorpions, mites, and ticks. • Comparethe characteristics of millipedes and centipedes.

34. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Chelicerata • The subphylum Chelicerata, the chelicerates, includes spiders, scorpions, mites, sea spiders, and horseshoe crabs. • Chelicerates lack antennae and typically have six pairs of appendages. • The first pair of appendages, the chelicerae, are modified into pincers or fangs.

35. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Chelicerata, continued Class Arachnida • Class Arachnida, the arachnids, includes spiders, scorpions, mites, and ticks. • The arachnid’s body is divided into: • a cephalothorax that usually bears six pairs of jointed appendages: • one pair of chelicerae • one pair of pedipalps • four pairs of walking legs • an abdomen

36. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Chelicerata, continued Anatomy of a Spider • Spiders have eight simple eyes and chelicerae that are modified as fangs. • Spiders produce silk threads using spinnerets. • Spiders respire through spiracles that connect to book lungs or tracheae. • Malpighian tubules function to excrete wastes while conserving water.

37. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Anatomy of a Brown Recluse Spider

38. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Spinneret

39. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Chelicerata, continued Life of a Spider • Spiders feed on insects and other small animals. Many species are adapted to capture certain prey. • Spiders rarely harm humans, but two species in the United States are dangerous: • the black widow • the brown recluse • A male spider is usually smaller than the female. • Females lay eggs in a silken case.

40. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Feeding Habits of Spiders

41. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Chelicerata, continued Scorpions • Scorpions have large, pincerlike pedipalps and a stinger on the last segment of the abdomen. Mites and Ticks • Mites and ticks have a completely fused cephalothorax and abdomen. • Many species are parasitic, and some spread diseases that affect humans.

42. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Subphylum Myriapoda • Members of the subphylum Myriapoda have antennae, mandibles, and unbranched appendages. Class Diplopoda • Millipedes have rounded bodies and two pairs of jointed legs on each body segment except the last two segments. Class Chilopoda • Centipedes have flattened bodies and one pair of jointed legs on each body segment except the first segment and the last two segments.

43. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Characteristics of Arachnids

44. Section 3 Subphyla Chelicerata and Myriapoda Chapter 36 Types of Arachnids

45. Chapter 36 Standardized Test Prep Multiple Choice 1. What do all arthropods have in common? A. spiracles B. antennae C. a cephalothorax D. jointed appendages

46. Chapter 36 Standardized Test Prep Multiple Choice, continued 1. What do all arthropods have in common? A. spiracles B. antennae C. a cephalothorax D. jointed appendages

47. Chapter 36 Standardized Test Prep Multiple Choice, continued 2. What is the chitin-containing structure that protects and supports the body of an arthropod? F. a tagma G. a chelicera H. an appendage J. an exoskeleton

48. Chapter 36 Standardized Test Prep Multiple Choice, continued 2. What is the chitin-containing structure that protects and supports the body of an arthropod? F. a tagma G. a chelicera H. an appendage J. an exoskeleton

49. Chapter 36 Standardized Test Prep Multiple Choice, continued 3. Which of the following statements about compound eyes is true? A. Compound eyes have a single lens. B. Compound eyes are located on the abdomen of scorpions. C. Compound eyes are found in all arthropods except crayfish. D. Compound eyes are composed of many individual light detectors.

50. Chapter 36 Standardized Test Prep Multiple Choice, continued 3. Which of the following statements about compound eyes is true? A. Compound eyes have a single lens. B. Compound eyes are located on the abdomen of scorpions. C. Compound eyes are found in all arthropods except crayfish. D. Compound eyes are composed of many individual light detectors.