2Chapter 26 Arthropods Section 1: Arthropod Characteristics Section 2: Arthropod DiversitySection 3: Insects and Their Relatives
3Arthropods have exoskeletons with jointed appendages. Chapter 26Arthropods26.1 Arthropod CharacteristicsArthropod FeaturesArthropods are segmented invertebrates with bilateral symmetry, coelomate body cavities, and protostome development.Arthropods have exoskeletons with jointed appendages.
426.1 Arthropod Characteristics Chapter 26Arthropods26.1 Arthropod CharacteristicsSegmentationThe head has mouthparts for feeding and various types of eyes.The thorax is the middle body region to which legs and wings are attached.The abdomen is the posterior end of the abdomen and bears additional legs and contains digestive structures and the reproductive organs.
5Provides a framework for support Chapter 26Arthropods26.1 Arthropod CharacteristicsExoskeletonProvides a framework for supportProtects soft body tissues and slows water loss in animals that live on landProvides a place for muscle attachmentMade of chitin
6Appendages of arthropods are adapted for a Chapter 26Arthropods26.1 Arthropod CharacteristicsJointed Appendagesvariety of functions,such as feeding, mating,sensing, walking, andswimming.Appendages of arthropods are adapted for aFlies have jointed appendages.
7Arthropods must shed their outer coverings in order to grow. Chapter 26Arthropods26.1 Arthropod CharacteristicsMoltingArthropods must shed their outer coverings in order to grow.
8produce digestive enzymes. Chapter 26Arthropods26.1 Arthropod CharacteristicsFeeding and DigestionArthropods have a complete, one-way digestive system with a mouth, gut, and an anus, along with various glands thatproduce digestive enzymes.Leafcutter ant
9Their circulatory systems transport nutrients and remove wastes. Chapter 26Arthropods26.1 Arthropod CharacteristicsRespirationArthropods obtain oxygen by using one of three structures—gills, tracheal tubes, or book lungs.CirculationTheir circulatory systems transport nutrients and remove wastes.Visualizing Respiratory Structures
10Cellular wastes are removed from the blood through Malpighian tubules. Chapter 26Arthropods26.1 Arthropod CharacteristicsExcretionCellular wastes are removed from the blood through Malpighian tubules.Malpighian tubules are attached to and empty into the gut, which contains the undigested food wastes to be eliminated from the body.
11A compound eye has many facets, which are hexagonal in shape. Chapter 26Arthropods26.1 Arthropod CharacteristicsVisionA compound eye has many facets, which are hexagonal in shape.Each facet sees part of an image.The brain combines the images into a mosaic.
12Chapter 26Arthropods26.1 Arthropod CharacteristicsHearingMany arthropods have a sense organ called a tympanum, which is a flat membrane used for hearing.Arthropod tympanums can be located on the forelegs, on the abdomen, or on the thorax.
13Chapter 26Arthropods26.1 Arthropod CharacteristicsChemicalsPheromones are chemicals secreted by many animal species that influence the behavior of other animals of the same species.
14The muscles are attached to the inner surface of the exoskeleton on Chapter 26Arthropods26.1 Arthropod CharacteristicsMovementThe muscles are attached to the inner surface ofthe exoskeleton onboth sides of the joint.The strength of muscle contraction depends on the rate at which nerve impulses stimulate muscles.
15The spiders and their relatives Chapter 26Arthropods26.2 Arthropod DiversityArthropod GroupsThe crustaceansThe spiders and their relativesThe insects and their relativesClassifying Arthropods
17Chapter 26Arthropods26.2 Arthropod DiversityCrustaceansMost are aquatic and have two pairs of antennae, two compound eyes that can be on the tips of slender movable stalks, and mandibles for chewing.Crustaceans possess branched appendages and have a free-swimming larval stage.
18legs—the chelipeds—has large claws adapted to catch and crush food. Chapter 26Arthropods26.2 Arthropod DiversityMost crustaceans, such as crayfishes, lobsters, and crabs, have five pairs of legs.The first pair oflegs—the chelipeds—has large claws adapted tocatch and crush food.Behind the next four pairs of walking legs are the swimmerets, appendages that are used for reproduction and as flippers during swimming.
19Spiders and Their Relatives Chapter 26Arthropods26.2 Arthropod DiversitySpiders and Their RelativesMost arachnids have two body sections—a cephalothorax and an abdomen—and six pairs of jointed appendages.An arachnid’s most anterior pair of appendages is modified into mouthparts called chelicerae.The second pair of appendages is called the pedipalps.
20Spiders are capable of constructing only specific kinds of webs. Chapter 26Arthropods26.2 Arthropod DiversitySpidersSpiders are capable of constructing only specific kinds of webs.A spider secretesdigestive enzymes onto its prey.The spider ingests the softened food.
21A male spider stores sperm in a cavity on his pedipalps. Chapter 26Arthropods26.2 Arthropod DiversityA male spider stores sperm in a cavity on his pedipalps.The male inserts the sperm into the female.The female lays her eggs in a cocoon spun of spider silk.There can be as many as 100 eggs in one cocoon.
22Other members of class Arachnida are ticks, mites, and scorpions. Chapter 26Arthropods26.2 Arthropod DiversityOther members of class Arachnida are ticks, mites, and scorpions.TickScorpion
23They feed on annelids, mollusks, and other invertebrates. Chapter 26Arthropods26.2 Arthropod DiversityHorseshoe CrabsHorseshoe crabs have remained unchanged since the Triassic Period more than 200 million years ago.The chelicerae, pedipalps, and the next three pairs of legs are used for walking and getting food from the bottom of the sea.They feed on annelids, mollusks, and other invertebrates.
24Horseshoe crabs come to shore to reproduce at high tide. Chapter 26Arthropods26.2 Arthropod DiversityHorseshoe crabs come to shore to reproduce at high tide.Horseshoe crab
25Arthropods make up about three-fourths of all named animal species. Chapter 26Arthropods26.3 Insects and Their RelativesDiversity of InsectsArthropods make up about three-fourths of all named animal species.About 80 percent of arthropods are insects.
26Three body areas—the head, thorax, and abdomen Chapter 26Arthropods26.3 Insects and Their RelativesExternal FeaturesThree body areas—the head, thorax, and abdomen
27Head structures include antennae, compound eyes, simple eyes, Chapter 26Arthropods26.3 Insects and Their RelativesHead structures include antennae, compoundeyes, simple eyes,and mouthparts.Insects have three pairs of legs and generally two pairs of wings on the thorax.
29Insect legs are adapted to a variety of functions. Chapter 26Arthropods26.3 Insects and Their RelativesInsect legs are adapted to a variety of functions.Legs with claws enable beetles to dig in soil or crawl under bark.Sticky pads on the ends of walking legs enable flies to walk upside down.Legs adapted for collecting pollenLegs adapted to jumpingLegs adapted to skimming over the surface of water
30Insects’ mouthparts are adapted to the food they eat. Chapter 26Arthropods26.3 Insects and Their RelativesInsects’ mouthparts are adapted to the food they eat.
32Insect wings are outgrowths of the body wall. Chapter 26Arthropods26.3 Insects and Their RelativesInsect wings are outgrowths of the body wall.Wings are formed of a thin double membrane of chitin, and they have rigid veins that give the wings strength.
33Insects have a variety of adaptations in their sense organs. Chapter 26Arthropods26.3 Insects and Their RelativesInsects have a variety of adaptations in their sense organs.Hairlike structures that are sensitive to touch, pressure, vibration, and odorDetect airborne sounds with their tympanic organsChemical receptors for taste and smell are located on mouthparts, antennae, or legs.
3426.3 Insects and Their Relatives Chapter 26Arthropods26.3 Insects and Their RelativesComplete MetamorphosisMost insects develop through the four stages of complete metamorphosis—egg, larva, pupa, and adult.
36Incomplete Metamorphosis Chapter 26Arthropods26.3 Insects and Their RelativesIncomplete MetamorphosisInsects that undergo incomplete metamorphosis hatch from eggs as nymphs.After several molts, young nymphs become winged adults.
37There are only three castes in a honeybee hive. Chapter 26Arthropods26.3 Insects and Their RelativesInsects such as honeybees, ants, and termites organize into social groups and cooperate in activities necessary for their survival.There are only three castes in a honeybee hive.WorkersDronesThe queen
38Honeybees have evolved an efficient system of Chapter 26Arthropods26.3 Insects and Their Relativescommunication, usingbodily movements toindicate the locationof food sources.Honeybees have evolved an efficient system ofWaggle danceRound dance
40Insects pollinate most flowering plants. Chapter 26Arthropods26.3 Insects and Their RelativesInsects pollinate most flowering plants.Insects also can be harmful to humans.Integrated pest management offers long-term control of pests.
41Centipedes and Millipedes Chapter 26Arthropods26.3 Insects and Their RelativesCentipedes and MillipedesCentipedes have long, segmented bodies, andeach segment has onepair of jointed legs.The first pair of appendages is modified to form poison claws.Most species of centipedes are not harmful to humans.Centipede
42Walk with a slow, graceful motion Chapter 26Arthropods26.3 Insects and Their RelativesMillipedes have two pairs of appendages on their abdominal segments and one pair on their thorax.Walk with a slow, graceful motionThey do not have poisonclaws and feed primarily on damp anddecaying vegetation.Millipede
43Evolution of Arthropods Chapter 26Arthropods26.3 Insects and Their RelativesEvolution of ArthropodsTrilobites, abundant in the mid-Cambrian, were early arthropods.Tardigrades also are related to arthropods.Trilobite
44Chapter Resource Menu Chapter Diagnostic Questions ArthropodsChapter Resource MenuChapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practicebiologygmh.comGlencoe Biology TransparenciesImage BankVocabularyAnimationClick on a hyperlink to view the corresponding lesson.
45What features do arthropods not share with annelids? Chapter 26ArthropodsChapter Diagnostic QuestionsWhat features do arthropods not sharewith annelids?segmentsinvertebratesexoskeletonscoelomate body cavities
46Which is not a body part of an arthropod? Chapter 26ArthropodsChapter Diagnostic QuestionsWhich is not a body part of an arthropod?headtailthoraxabdomen
47An arthropod’s exoskeleton is made of what material? Chapter 26ArthropodsChapter Diagnostic QuestionsAn arthropod’s exoskeleton is made ofwhat material?chitinsilicabonecartilage
48Which characteristic of arthropods distinguishes them from annelids? Chapter 26Arthropods26.1 Formative QuestionsWhich characteristic ofarthropods distinguishesthem from annelids?segmentationbilateral symmetrycoelomate body cavitypresence of anexoskeleton
49What are mandibles? feeding appendages grasping antennae Chapter 26Arthropods26.1 Formative QuestionsWhat are mandibles?feeding appendagesgrasping antennaepinching clawsrespiratory openings
50What excretory organs help terrestrial Chapter 26Arthropods26.1 Formative QuestionsWhat excretory organs help terrestrialarthropods preserve water in their bodies?book lungsMalpighian tubulesspiraclestracheal tubes
51What is a tympanum used to detect? Chapter 26Arthropods26.1 Formative QuestionsWhat is a tympanum used to detect?chemicalsodorsmovementsound waves
52Which arthropods have five pairs of legs? Chapter 26Arthropods26.2 Formative QuestionsWhich arthropods have five pairs of legs?insectslobstersscorpionsticks
53Which arthropods do not have antennae? Chapter 26Arthropods26.2 Formative QuestionsWhich arthropods do not have antennae?beetlescrayfishgrasshoppersspiders
54Which is a function of chelicerae? Chapter 26Arthropods26.2 Formative QuestionsWhich is a function of chelicerae?chewing foodpoisoning preysecreting silksensing odors
55Which describes a horseshoe crab? Chapter 26Arthropods26.2 Formative QuestionsWhich describes a horseshoe crab?a living fossilan evolutionary linka copepod ancestora primitive crustacean
56What are insect wings composed of? Chapter 26Arthropods26.3 Formative QuestionsWhat are insect wings composed of?calciumchitinproteinpolysaccharide
57What structures enable insects to detect Chapter 26Arthropods26.3 Formative QuestionsWhat structures enable insects to detecttouch, pressure, vibration, or odor?antennaehairsmouthpartstympanums
58Which word best describes metamorphosis? Chapter 26Arthropods26.3 Formative QuestionsWhich word best describes metamorphosis?alterationgrowthdevelopmenttransformation
59In honeybee and ant societies, what is the Chapter 26Arthropods26.3 Formative QuestionsIn honeybee and ant societies, what is therole of a female that does not reproduce?dronequeensoldierworker
60Based on this interpretation of the phylogeny Chapter 26ArthropodsChapter Assessment QuestionsBased on this interpretation of the phylogenyof arthropods, which group developed mostrecently?trilobitesinsects andcrustaceansarachnidschelicerae
61Which is the method of seed dispersal for this seed? Chapter 26ArthropodsChapter Assessment QuestionsWhich is the method of seed dispersal forthis seed?animalsgravitywaterwind
62Which stage is absent for insects that Chapter 26ArthropodsChapter Assessment QuestionsWhich stage is absent for insects thatundergo incomplete metamorphosis?
64Why is molting a necessary process in arthropods? Chapter 26ArthropodsStandardized Test PracticeWhy is molting a necessary process inarthropods?for growthfor excretionfor reproductionfor respiration
65What is the primary function of the circulatory Chapter 26ArthropodsStandardized Test PracticeWhat is the primary function of the circulatorysystem in most arthropods?to conserve waterto deliver oxygento provide energyto transport nutrients
66How does an arthropod with compound eyes perceive an object? Chapter 26ArthropodsStandardized Test PracticeHow does an arthropod with compound eyesperceive an object?as a mosaicas black and whiteas a focused shapeas a network of lines
67Which appendages does a lobster use for swimming? Chapter 26ArthropodsStandardized Test PracticeWhich appendages does a lobster use forswimming?
68The specific kind of web that a spider Chapter 26ArthropodsStandardized Test PracticeTrue or FalseThe specific kind of web that a spiderconstructs is genetically programmed.
69Which is a stage of development in incomplete metamorphosis? Chapter 26ArthropodsStandardized Test PracticeWhich is a stage of development inincomplete metamorphosis?caterpillarlarvanymphpupa
70At which stage of metamorphosis does this organism behave like a Chapter 26ArthropodsStandardized Test PracticeAt which stage ofmetamorphosisdoes this organismbehave like afeeding machine?