1. Section 1 Phylum Arthropoda
Chapter 36
Objectives
Describe the distinguishing characteristics of arthropods.
Explain the process of molting in an arthropod.
List the five major subphyla of the phylum Arthropoda.

2. Characteristics of Arthropods
Section 1 Phylum Arthropoda
Chapter 36
Characteristics of Arthropods
The members of the phylum Arthropoda are called _____________.
Arthropods are segmented animals with body segments that bear ______________.
Arthropods have an exoskeleton that provides protection and support and contains chitin.
Arthropods show a high degree of cephalization. Most have segmented antennae and ______________________

3. Characteristics of Arthropods, continued
Section 1 Phylum Arthropoda
Chapter 36
Characteristics of Arthropods, continued
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 __________.
An anthropod goes through many cycles of molting during its life.

4. Characteristics of Arthropods
Section 1 Phylum Arthropoda
Chapter 36
Characteristics of Arthropods

5. Evolution and Classification, continued
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 _________ (plural, tagmata).

6. Evolution and Classification, continued
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:
________________, which are jawlike
______________ (singular, chelicera), which are pincerlike
The five main subphyla are:
Trilobita
Crustacea
Chelicerata
Myriapoda
Hexapoda

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

8. Chapter 36 Objectives Describe the characteristics of crustaceans.
Section 2 Subphylum Crustacea
Chapter 36
Objectives
Describe the characteristics of crustaceans.
Compare aquatic crustaceans with terrestrial crustaceans.
Explain the functions of the appendages on a crayfish.
Summarize digestion, respiration, circulation, excretion, and neural control in crayfish.

9. Chapter 36 Characteristics
Section 2 Subphylum Crustacea
Chapter 36
Characteristics
The subphylum Crustacea contains about _________ known species.
Crustaceans are so diverse that their single defining characteristic is having _____________of antennae.
Most crustaceans also have:
a pair of ________________
a pair of appendages on each body segment
some branched appendages
____ to _____ segments and several tagmata

10. Characteristics, continued
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 _____________________.

11. Diversity of Crustaceans
Section 2 Subphylum Crustacea
Chapter 36
Diversity of Crustaceans
Aquatic Crustaceans
____________ 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 _____________ 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.

12. Diversity of Crustaceans, continued
Section 2 Subphylum Crustacea
Chapter 36
Diversity of Crustaceans, continued
Terrestrial Crustaceans
Sow bugs and pill bugs are terrestrial ___________.
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.

13. 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 __________, or members of the order Decapoda. Decapoda means “10 feet.”
Decapods have five pairs of legs that are used for locomotion.

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

15. The Crayfish, continued
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

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

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

18. The Crayfish, continued
Section 2 Subphylum Crustacea
Chapter 36
The Crayfish, continued
Excretion
________________________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.

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

20. Section 3 Subphyla Chelicerata and Myriapoda
Chapter 36
Objectives
List the characteristics of arachnids, as represented by a spider.
Explain the adaptations that spiders have for a predatory life on land.
Identify the unique characteristics of scorpions, mites, and ticks.
Compare the characteristics of millipedes and centipedes.

21. Subphylum Chelicerata
Section 3 Subphyla Chelicerata and Myriapoda
Chapter 36
Subphylum Chelicerata
The subphylum Chelicerata, the _______________, 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 ____________, are modified into pincers or fangs.

22. Subphylum Chelicerata, continued
Section 3 Subphyla Chelicerata and Myriapoda
Chapter 36
Subphylum Chelicerata, continued
Class Arachnida
Class Arachnida, the ______________, 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 ____________
one pair of ______________
four pairs of walking legs
an abdomen

23. Subphylum Chelicerata, continued
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 ______________.
Spiders respire through ___________ that connect to _______________or ________________.
_______________________ function to excrete wastes while conserving water.

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

25. Section 3 Subphyla Chelicerata and Myriapoda
Chapter 36
Spinneret

26. Subphylum Chelicerata, continued
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 ________________
the _________________
A male spider is usually smaller than the female.
Females lay eggs in a silken case.

27. Subphylum Chelicerata, continued
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 _______________ cephalothorax and abdomen.
Many species are parasitic, and some spread diseases that affect humans.

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

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

30. Multiple Choice, continued
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

31. Multiple Choice, continued
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

32. Multiple Choice, continued
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

33. Multiple Choice, continued
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.

34. Multiple Choice, continued
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.

35. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
4. What are the major respiratory organs of crayfish?
F. gills
G. lungs
H. tracheae
J. book lungs

36. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
4. What are the major respiratory organs of crayfish?
F. gills
G. lungs
H. tracheae
J. book lungs

37. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
5. How do mites and ticks differ from spiders?
A. Mites and ticks have mandibles.
B. Mites and ticks have two pairs of antennae.
C. Mites and ticks have a unique respiratory system.
D. Mites and ticks have a fused cephalothorax and abdomen.

38. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
5. How do mites and ticks differ from spiders?
A. Mites and ticks have mandibles.
B. Mites and ticks have two pairs of antennae.
C. Mites and ticks have a unique respiratory system.
D. Mites and ticks have a fused cephalothorax and abdomen.

39. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
The illustration below shows four animals. Use the illustration to answer the question that follows.

40. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
6. Which animal has a chitinous exoskeleton?
F. snail
G. grasshopper
H. hydra
J. squid

41. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
6. Which animal has a chitinous exoskeleton?
F. snail
G. grasshopper
H. hydra
J. squid

42. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
7. mandible : crayfish :: chelicera :
A. pill bug
B. scorpion
C. barnacle
D. millipede

43. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
7. mandible : crayfish :: chelicera :
A. pill bug
B. scorpion
C. barnacle
D. millipede

44. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
The graph below shows data about molting and two causes of mortality in crabs. Use the graph to answer the questions that follow.

45. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
8. During which months are you most likely to find crabs in molt?
F. January through March
G. April through June
H. July through September
J. September through January

46. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
8. During which months are you most likely to find crabs in molt?
F. January through March
G. April through June
H. July through September
J. September through January

47. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
9. What is the relationship between molting and mortality?
A. Molting increases mortality.
B. Molting decreases mortality.
C. Molting has no effect on mortality.
D. Molting and mortality occur at different times of the year.

48. Multiple Choice, continued
Chapter 36
Standardized Test Prep
Multiple Choice, continued
9. What is the relationship between molting and mortality?
A. Molting increases mortality.
B. Molting decreases mortality.
C. Molting has no effect on mortality.
D. Molting and mortality occur at different times of the year.

49. Chapter 36 Short Response
Standardized Test Prep
Short Response
Some arthropods are terrestrial and some are aquatic.
Give examples and describe the distinguishing characteristics of each type of arthropod.

50. Short Response, continued
Chapter 36
Standardized Test Prep
Short Response, continued
Some arthropods are terrestrial and some are aquatic.
Give examples and describe the distinguishing characteristics of each type of arthropod.
Answer: Spiders and millipedes are terrestrial. The exoskeleton is lighter, respiration is by book lungs or tracheae, and water is conserved. Crayfish and crabs are aquatic, the exoskeleton is heavier, respiration is by gills, and excess water is excreted by green glands.

51. Chapter 36 Extended Response
Standardized Test Prep
Extended Response
Base your answers to parts A & B on the information below.
All arthropods undergo many cycles of molting throughout their lifetime.
Part A Describe the process of molting in arthropods.
Part B Explain how the anatomical structure of an arthropod relates to the function of molting.

52. Extended Response, continued
Chapter 36
Standardized Test Prep
Extended Response, continued
Answer:
Part A In between molts, the tissues swell and put pressure on the exoskeleton. Molting is then induced by hormones. Enzymes digest the old exoskeleton and the epidermis synthesizes a new one. The old exoskeleton then loosens, breaks along specific lines, and is shed.
Part B: The exoskeleton covers the body and therefore limits growth. Molting provides a means for allowing growth.