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Mata Kuliah Zoologi Invertebrata

Mata Kuliah Zoologi Invertebrata

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  • 1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 33 Invertebrates
  • 2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Overview: Life Without a Backbone • Invertebrates – Are animals that lack a backbone – Account for 95% of known animal species Figure 33.1
  • 3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • A review of animal phylogeny Ancestral colonial choanoflagellate Eumetazoa Bilateria Deuterostomia Porifera Cnidaria Otherbilaterians(including Nematoda,Arthropoda, Mollusca,andAnnelida) Echinodermata Chordata Figure 33.2
  • 4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Exploring invertebrate diversity PORIFERA (5,500 species) A sponge CNIDARIA (10,000 species) A jelly PLACOZOA (1 species) KINORHYNCHA (150 species) 0.5 mm A placozoan (LM) A kinorhynch (LM) 250 µm PLATYHELMINTHES (20,000 species) ROTIFERA (1,800 species) A marine flatworm A rotifer (LM) ECTOPROCTA (4,500 species) PHORONIDA (20 species) Ectoprocts PhoronidsFigure 33.3
  • 5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Exploring invertebrate diversity BRACHIOPODA (335 species) NEMERTEA (900 species) A brachiopod A ribbon worm ACANTHOCEPHALA (1,100 species) CTENOPHORA (100 species) An acanthocephalan A ctenophore, or comb jelly MOLLUSCA (93,000 species) ANNELIDA (16,500 species) An octopus A marine annelid LORICIFERA (10 species) PRIAPULA (16 species) 5 mm 50 µm A loriciferan (LM) A priapulanFigure 33.3
  • 6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Exploring invertebrate diversity NEMATODA (25,000 species) ARTHROPODA (1,000,000 + species) A roundworm A scorpion (an arachnid) CYCLIOPHORA (1 species) TARDIGRADA (800 species) 100 µm 100 µm A cycliophoran (colorized SEM) Tardigrades (colorized SEM) ONYCHOPHORA (110 species) HEMICHORDATA (85 species) An onychophoran An acorn worm ECHINODERMATA (7,000 species) CHORDATA (52,000 species) A sea urchin A tunicateFigure 33.3
  • 7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Sponges are sessile and have a porous body and choanocytes • Sponges, phylum Porifera – Live in both fresh and marine waters – Lack true tissues and organs
  • 8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Sponges are suspension feeders – Capturing food particles suspended in the water that passes through their body Azure vase sponge (Callyspongia plicifera) Osculum Spicules Water flow Flagellum Collar Food particles in mucus Choanocyte Phagocytosis of food particles Amoebocyte Choanocytes. The spongocoel is lined with feeding cells called choanocytes. By beating flagella, the choanocytes create a current that draws water in through the porocytes. Spongocoel. Water passing through porocytes enters a cavity called the spongocoel. Porocytes. Water enters the epidermis through channels formed by porocytes, doughnut-shaped cells that span the body wall. Epidermis. The outer layer consists of tightly packed epidermal cells. Mesohyl. The wall of this simple sponge consists of two layers of cells separated by a gelatinous matrix, the mesohyl (“middle matter”). The movement of the choanocyte flagella also draws water through its collar of fingerlike projections. Food particles are trapped in the mucus coating the projections, engulfed by phagocytosis, and either digested or transferred to amoebocytes. Amoebocyte. Amoebocytes transport nutrients to other cells of the sponge body and also produce materials for skeletal fibers (spicules). 5 6 7 4 3 2 1 Figure 33.4
  • 9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Choanocytes, flagellated collar cells – Generate a water current through the sponge and ingest suspended food • Most sponges are hermaphrodites – Meaning that each individual functions as both male and female
  • 10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.2: Cnidarians have radial symmetry, a gastrovascular cavity, and cnidocytes • All animals except sponges – Belong to the clade Eumetazoa, the animals with true tissues • Phylum Cnidaria – Is one of the oldest groups in this clade
  • 11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Cnidarians – Have diversified into a wide range of both sessile and floating forms including jellies, corals, and hydras – But still exhibit a relatively simple diploblastic, radial body plan
  • 12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The basic body plan of a cnidarian – Is a sac with a central digestive compartment, the gastrovascular cavity • A single opening – Functions as both mouth and anus
  • 13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • There are two variations on this body plan – The sessile polyp and the floating medusa Mouth/anus Tentacle Gastrovascular cavity Gastrodermis Mesoglea Epidermis Tentacle Body stalk Mouth/anus MedusaPolyp Figure 33.5
  • 14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tentacle “Trigger” Nematocyst Coiled thread Discharge Of thread Cnidocyte Prey Figure 33.6 • Cnidarians are carnivores – That use tentacles to capture prey • The tentacles are armed with cnidocytes – Unique cells that function in defense and the capture of prey
  • 15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The phylum Cnidaria is divided into four major classes Table 33.1
  • 16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Hydrozoa, Scyphozoa, Cubozoa, and Anthozoa (a) These colonial polyps are members of class Hydrozoa. (b) Many species of jellies (class Scyphozoa), including the species pictured here, are bioluminescent. The largest scyphozoans have tentacles more than 100 m long dangling from a bell-shaped body up to 2 m in diameter. (c) The sea wasp (Chironex fleckeri) is a member of class Cubozoa. Its poison, which can subdue fish and other large prey, is more potent than cobra venom. (d) Sea anemones and other members of class Anthozoa exist only as polyps. Figure 33.7a–d
  • 17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hydrozoans • Most hydrozoans – Alternate between polyp and medusa forms Feeding polyp Reproductive polyp Medusa bud ASEXUAL REPRODUCTION (BUDDING) Gonad Medusa MEIOSIS FERTILIZATION SEXUAL REPRODUCTION Egg Sperm Developing polyp Portion of a colony of polyps Mature polyp Planula (larva) Key Haploid (n) Diploid (2n)1 mm Zygote Figure 33.8 A colony of interconnected polyps (inset, LM) results from asexual reproduction by budding. 1 Some of the colony’s polyps, equipped with tentacles, are specialized for feeding. 2 Other polyps, specialized for reproduction, lack tentacles and produce tiny medusae by asexual budding. 3 The medusae swim off, grow, and reproduce sexually. 4 The zygote develops into a solid ciliated larva called a planula. 5The planula eventually settles and develops into a new polyp. 6
  • 18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Scyphozoans • In the class Scyphozoa – Jellies (medusae) are the prevalent form of the life cycle
  • 19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cubozoans • In the class Cubozoa, which includes box jellies and sea wasps – The medusa is box-shaped and has complex eyes
  • 20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Anthozoans • Class Anthozoa includes the corals and sea anemones – Which occur only as polyps
  • 21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.3: Most animals have bilateral symmetry • The vast majority of animal species belong to the clade Bilateria – Which consists of animals with bilateral symmetry and triploblastic development
  • 22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Flatworms • Members of phylum Platyhelminthes – Live in marine, freshwater, and damp terrestrial habitats – Are flattened dorsoventrally and have a gastrovascular cavity • Although flatworms undergo triploblastic development – They are acoelomates
  • 23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Flatworms are divided into four classes Table 33.2
  • 24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Turbellarian • Turbellarians – Are nearly all free-living and mostly marine Figure 33.9
  • 25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The best-known turbellarians, commonly called planarians – Have light-sensitive eyespots and centralized nerve nets Pharynx. The mouth is at the tip of a muscular pharynx that extends from the animal’s ventral side. Digestive juices are spilled onto prey, and the pharynx sucks small pieces of food into the gastrovascular cavity, where digestion continues. Digestion is completed within the cells lining the gastro- vascular cavity, which has three branches, each with fine subbranches that pro- vide an extensive surface area. Undigested wastes are egested through the mouth. Ganglia. Located at the anterior end of the worm, near the main sources of sensory input, is a pair of ganglia, dense clusters of nerve cells. Ventral nerve cords. From the ganglia, a pair of ventral nerve cords runs the length of the body. Gastrovascular cavity Eyespots Figure 33.10
  • 26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Monogeneans and Trematode • Monogeneans and trematodes – Live as parasites in or on other animals – Parasitize a wide range of hosts
  • 27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Trematodes that parasitize humans – Spend part of their lives in snail hosts These larvae penetrate the skin and blood vessels of humans working in irrigated fields contaminated with infected human feces. Asexual reproduction within a snail results in another type of motile larva, which escapes from the snail host. Blood flukes reproduce sexually in the human host. The fertilized eggs exit the host in feces. The eggs develop in water into ciliated larvae. These larvae infect snails, the intermediate hosts. Snail host 1 mm Female Male 5 2 3 4 Figure 33.11 Mature flukes live in the blood vessels of the human intestine. A female fluke fits into a groove running the length of the larger male’s body, as shown in the light micrograph at right. 1
  • 28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Most monogeneans – Are parasites of fish
  • 29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tapeworm • Tapeworms – Are also parasitic and lack a digestive system Proglottids with reproductive structures 200 µm Hooks Sucker Scolex Figure 33.12
  • 30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Rotifers • Rotifers, phylum Rotifera – Are tiny animals that inhabit fresh water, the ocean, and damp soil
  • 31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Rotifers are smaller than many protists – But are truly multicellular and have specialized organ systems 0.1 mm Figure 33.13
  • 32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Rotifers have an alimentary canal – A digestive tube with a separate mouth and anus that lies within a fluid-filled pseudocoelom • Rotifers reproduce by parthenogenesis – In which females produce more females from unfertilized eggs
  • 33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lophophorates: Ectoprocts, Phoronids, and Brachiopods • Lophophorates have a lophophore – A horseshoe-shaped, suspension-feeding organ bearing ciliated tentacles
  • 34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Ectoprocts – Are colonial animals that superficially resemble plants Lophophore Ectoprocts, such as this sea mat (Membranipora membranacea), are colonial lophophorates. (a) Figure 33.14a
  • 35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Phoronids – Are tube-dwelling marine worms ranging from 1 mm to 50 cm in length Lophophore In phoronids such as Phoronis hippocrepia, the lophophore and mouth are at one end of an elongated trunk. (b) Figure 33.14b
  • 36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Brachiopods superficially resemble clams and other hinge-shelled molluscs – But the two halves of the shell are dorsal and ventral rather than lateral, as in clams Lophophore Brachiopods have a hinged shell. The two parts of the shell are dorsal and ventral. (c) Figure 33.14c
  • 37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Nemerteans • Members of phylum Nemertea – Are commonly called proboscis worms or ribbon worms Figure 33.15
  • 38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The nemerteans unique proboscis – Is used for defense and prey capture – Is extended by a fluid-filled sac • Nemerteans also have a closed circulatory system – In which the blood is contained in vessels distinct from fluid in the body cavity
  • 39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.4: Molluscs have a muscular foot, a visceral mass, and a mantle • Phylum Mollusca – Includes snails and slugs, oysters and clams, and octopuses and squids • Most molluscs are marine – Though some inhabit fresh water and some are terrestrial • Molluscs are soft-bodied animals – But most are protected by a hard shell
  • 40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • All molluscs have a similar body plan with three main parts – A muscular foot – A visceral mass – A mantle
  • 41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Visceral mass Mantle Foot Coelom Intestine Gonads Mantle cavity Anus Gill Nerve cords Esophagus Stomach Shell Radula Mouth Mouth Nephridium. Excretory organs called nephridia remove metabolic wastes from the hemolymph. Heart. Most molluscs have an open circulatory system. The dorsally located heart pumps circulatory fluid called hemolymph through arteries into sinuses (body spaces). The organs of the mollusc are thus continually bathed in hemolymph. The long digestive tract is coiled in the visceral mass. Radula. The mouth region in many mollusc species contains a rasp-like feeding organ called a radula. This belt of backward- curved teeth slides back and forth, scraping and scooping like a backhoe. The nervous system consists of a nerve ring around the esophagus, from which nerve cords extend. Figure 33.16
  • 42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Most molluscs have separate sexes – With gonads located in the visceral mass • The life cycle of many molluscs – Includes a ciliated larval stage called a trochophore
  • 43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • There are four major classes of molluscs Table 33.3
  • 44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chitons • Class Polyplacophora is composed of the chitons – Oval-shaped marine animals encased in an armor of eight dorsal plates Figure 33.17
  • 45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gastropods • About three-quarters of all living species of molluscs – Belong to class Gastropoda A land snail(a) A sea slug. Nudibranchs, or sea slugs, lost their shell during their evolution. (b) Figure 33.18a, b
  • 46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Most gastropods – Are marine, but there are also many freshwater and terrestrial species – Possess a single, spiraled shell • Slugs lack a shell – Or have a reduced shell
  • 47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The most distinctive characteristic of this class – Is a developmental process known as torsion, which causes the animal’s anus and mantle to end up above its head Anus Mantle cavity Stomach Intestine Mouth Figure 33.19
  • 48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bivalves • Molluscs of class Bivalvia – Include many species of clams, oysters, mussels, and scallops – Have a shell divided into two halves Figure 33.20
  • 49. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The mantle cavity of a bivalve – Contains gills that are used for feeding as well as gas exchange Hinge area Gut Coelom Heart Adductor muscle Anus Excurrent siphon Water flow Incurrent siphonGill Mantle cavity Foot Palp Mouth Shell Mantle Figure 33.21
  • 50. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cephalopods • Class Cephalopoda includes squids and octopuses – Carnivores with beak-like jaws surrounded by tentacles of their modified foot
  • 51. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Most octopuses – Creep along the sea floor in search of prey Figure 33.22a (a) Octopuses are considered among the most intelligent invertebrates.
  • 52. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Squids use their siphon – To fire a jet of water, which allows them to swim very quickly Figure 33.22b (b) Squids are speedy carnivores with beaklike jaws and well-developed eyes.
  • 53. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings ` • One small group of shelled cephalopods – The nautiluses, survives today Figure 33.22c (c) Chambered nautiluses are the only living cephalopods with an external shell.
  • 54. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.5: Annelids are segmented worms • Annelids – Have bodies composed of a series of fused rings
  • 55. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The phylum Annelida is divided into three classes Table 33.4
  • 56. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Oligochaetes • Oligochaetes (class Oligochaeta) – Are named for their relatively sparse chaetae, or bristles made of chitin – Include the earthworms and a variety of aquatic species
  • 57. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Earthworms eat their way through the soil, extracting nutrients as the soil moves through the alimentary canal – Which helps till the earth, making earthworms valuable to farmers
  • 58. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Anatomy of an earthworm Mouth Subpharyngeal ganglion Pharynx Esophagus Crop Gizzard Intestine Metanephridium Ventral vessel Nerve cords Nephrostome Intestine Dorsal vessel Longitudinal muscle Circular muscle Epidermis Cuticle Septum (partition between segments) Anus Each segment is surrounded by longitudinal muscle, which in turn is surrounded by circular muscle. Earthworms coordinate the contraction of these two sets of muscles to move (see Figure 49.25). These muscles work against the noncompressible coelomic fluid, which acts as a hydrostatic skeleton. Coelom. The coelom of the earthworm is partitioned by septa. Metanephridium. Each segment of the worm contains a pair of excretory tubes, called metanephridia, with ciliated funnels, called nephrostomes. The metanephridia remove wastes from the blood and coelomic fluid through exterior pores. Tiny blood vessels are abundant in the earthworm’s skin, which functions as its respiratory organ. The blood contains oxygen-carrying hemoglobin. Ventral nerve cords with segmental ganglia. The nerve cords penetrate the septa and run the length of the animal, as do the digestive tract and longitudinal blood vessels. The circulatory system, a network of vessels, is closed. The dorsal and ventral vessels are linked by segmental pairs of vessels. The dorsal vessel and five pairs of vessels that circle the esophagus of an earthworm are muscular and pump blood through the circulatory system. Cerebral ganglia. The earthworm nervous system features a brain-like pair of cerebral ganglia above and in front of the pharynx. A ring of nerves around the pharynx connects to a subpharyngeal ganglion, from which a fused pair of nerve cords runs posteriorly. Chaetae. Each segment has four pairs of chaetae, bristles that provide traction for burrowing. Many of the internal structures are repeated within each segment of the earthworm. Giant Australian earthworm Clitellum Table 33.23
  • 59. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Polychaetes • Members of class Polychaeta – Possess paddlelike parapodia that function as gills and aid in locomotion Parapodia Figure 33.24
  • 60. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Leeches • Members of class Hirudinea – Are blood-sucking parasites, such as leeches Figure 33.25
  • 61. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.6: Nematodes are nonsegmented pseudocoelomates covered by a tough cuticle • Among the most widespread of all animals, nematodes, or roundworms – Are found in most aquatic habitats, in the soil, in moist tissues of plants, and in the body fluids and tissues of animals
  • 62. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The cylindrical bodies of nematodes (phylum Nematoda) – Are covered by a tough coat called a cuticle 25 µm Figure 33.26
  • 63. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Some species of nematodes – Are important parasites of plants and animals 50 µmEncysted juveniles Muscle tissue Figure 33.27
  • 64. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.7: Arthropods are segmented coelomates that have an exoskeleton and jointed appendages • Two out of every three known species of animals are arthropods • Members of the phylum Arthropoda – Are found in nearly all habitats of the biosphere
  • 65. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings General Characteristics of Arthropods • The diversity and success of arthropods – Are largely related to their segmentation, hard exoskeleton, and jointed appendages
  • 66. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Early arthropods, such as trilobites – Showed little variation from segment to segment Figure 33.28
  • 67. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • As arthropods evolved – The segments fused, and the appendages became more specialized • The appendages of some living arthropods – Are modified for many different functions Antennae (sensory reception) Head Thorax Swimming appendages Walking legs Mouthparts (feeding)Pincer (defense) AbdomenCephalothorax Figure 33.29
  • 68. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The body of an arthropod – Is completely covered by the cuticle, an exoskeleton made of chitin • When an arthropod grows – It molts its exoskeleton in a process called ecdysis
  • 69. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Arthropods have an open circulatory system – In which fluid called hemolymph is circulated into the spaces surrounding the tissues and organs • A variety of organs specialized for gas exchange – Have evolved in arthropods
  • 70. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Molecular evidence now suggests – That living arthropods consist of four major lineages that diverged early in the evolution of the phylum Table 33.5
  • 71. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cheliceriforms • Cheliceriforms, subphylum Cheliceriformes – Are named for clawlike feeding appendages called chelicerae – Include spiders, ticks, mites, scorpions, and horseshoe crabs
  • 72. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Most of the marine cheliceriforms are extinct – But some species survive today, including the horseshoe crabs Figure 33.30
  • 73. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Scorpions have pedipalps that are pincers specialized for defense and the capture of food. The tip of the tail bears a poisonous stinger. (a) Dust mites are ubiquitous scavengers in human dwellings but are harmless except to those people who are allergic to them (colorized SEM). (b) Web-building spiders are generally most active during the daytime. (c) 50 µm Figure 33.31a–c • Most modern cheliceriforms are arachnids – A group that includes spiders, scorpions, ticks, and mites
  • 74. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Arachnids have an abdomen and a cephalothorax – Which has six pairs of appendages, the most anterior of which are the chelicerae Digestive gland Intestine Heart Stomach Brain Eyes Poison gland PedipalpChelicera Book lung Sperm receptacle Gonopore (exit for eggs)Silk gland Spinnerets Anus Ovary Figure 33.32
  • 75. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Myriapods • Subphylum Myriapoda – Includes millipedes and centipedes
  • 76. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Millipedes, class Diplopoda – Have a large number of legs • Each trunk segment – Has two pairs of legs Figure 33.33
  • 77. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Centipedes, class Chilopoda – Are carnivores with jaw-like mandibles – Have one pair of legs per trunk segment Figure 33.34
  • 78. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Insects • Subphylum Hexapoda, insects and their relatives – Are more species-rich than all other forms of life combined – Live in almost every terrestrial habitat and in fresh water
  • 79. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The internal anatomy of an insect – Includes several complex organ systems Compound eye Antennae Anus Vagina Ovary Dorsal artery Crop Abdomen Thorax Head The insect body has three regions: head, thorax, and abdomen. The segmentation of the thorax and abdomen are obvious, but the segments that form the head are fused. Heart. The insect heart drives hemolymph through an open circulatory system. Cerebral ganglion. The two nerve cords meet in the head, where the ganglia of several anterior segments are fused into a cerebral ganglion (brain). The antennae, eyes, and other sense organs are concentrated on the head. Tracheal tubes. Gas exchange in insects is accomplished by a tracheal system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells. The tracheal system opens to the outside of the body through spiracles, pores that can control air flow and water loss by opening or closing. Nerve cords. The insect nervous system consists of a pair of ventral nerve cords with several segmental ganglia. Insect mouthparts are formed from several pairs of modified appendages. The mouthparts include mandibles, which grasshoppers use for chewing. In other insects, mouthparts are specialized for lapping, piercing, or sucking. Malpighian tubules. Metabolic wastes are removed from the hemolymph by excretory organs called Malpighian tubules, which are out- pocketings of the digestive tract. Figure 33.35
  • 80. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Flight is obviously one key to the great success of insects • An animal that can fly – Can escape predators, find food, and disperse to new habitats much faster than organisms that can only crawl
  • 81. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Many insects – Undergo metamorphosis during their development • In incomplete metamorphosis, the young, called nymphs – Resemble adults but are smaller and go through a series of molts until they reach full size
  • 82. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Insects with complete metamorphosis – Have larval stages specialized for eating and growing that are known by such names as maggot, grub, or caterpillar • The larval stage – Looks entirely different from the adult stage
  • 83. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Metamorphosis from the larval stage to the adult stage – Occurs during a pupal stage Larva (caterpillar)(a) (b) Pupa (c) Pupa (d) Emerging adult (e) AdultFigure 33.6a–e
  • 84. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Insects are classified into about 26 orders ORDER Blattodea 4,000 Cockroaches have a dorsoventrally flattened body, with legs modified for rapid running. Forewings, when present, are leathery, whereas hind wings are fanlike. Fewer than 40 cock- roach species live in houses; the rest exploit habitats ranging from tropical forest floors to caves and deserts. Beetles comprise the most species-rich order of insects. They have two pairs of wings, one of which is thick and leathery, the other membranous. They have an armored exoskeleton and mouthparts adapted for biting and chewing. Beetles undergo complete metamorphosis. Earwigs are generally nocturnal scavengers. While some species are wingless, others have two pairs of wings, one of which is thick and leathery, the other membranous. Earwigs have biting mouthparts and large posterior pincers. They un- dergo incomplete metamorphosis. Dipterans have one pair of wings; the second pair has become modified into balancing organs called halteres. Their head is large and mobile; their mouthparts are adapted for sucking, piercing, or lapping. Dipterans undergo complete metamorpho- sis. Flies and mosquitoes are among the best-known dipterans, which live as scavengers, predators, and parasites. Hemipterans are so-called “true bugs,” including bed bugs, assassin bugs, and chinch bugs. (Insects in other orders are sometimes erroneously called bugs.) Hemipterans have two pairs of wings, one pair partly leathery, the other membranous. They have piercing or sucking mouthparts and undergo incomplete metamorphosis. Ants, bees, and wasps are generally highly social insects. They have two pairs of membranous wings, a mobile head, and chewing or sucking mouthparts. The females of many species have a posterior stinging organ. Hymenopterans undergo com- plete metamorphosis. Termites are widespread social insects that produce enormous colonies. It has been estimated that there are 700 kg of termites for every person on Earth! Some termites have two pairs of membranous wings, while others are wingless. They feed on wood with the aid of microbial symbionts carried in specialized chambers in their hindgut. Coleoptera 350,000 Dermaptera 1,200 Diptera 151,000 Hemiptera 85,000 Hymenoptera 125,000 Isoptera 2,000 APPROXIMATE NUMBER OF SPECIES MAIN CHARACTERISTICS EXAMPLES German cockroach Japanese beetle Earwig Horsefly Leaf- Footed bug Cicada-killer wasp Termite Figure 33.37
  • 85. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Insects are classified into about 26 orders Lepidoptera 120,000 Butterflies and moths are among the best-known insects. They have two pairs of wings covered with tiny scales. To feed, they uncoil a long proboscis. Most feed on nectar, but some species feed on other substances, including animal blood or tears. Odonata 5,000 Dragonflies and damselflies have two pairs of large, membran- ous wings. They have an elongated abdomen, large, compound eyes, and chewing mouthparts. They undergo incomplete meta- morphosis and are active predators. Orthoptera 13,000 Grasshoppers, crickets, and their relatives are mostly herbi- vorous. They have large hind legs adapted for jumping, two pairs of wings (one leathery, one membranous), and biting or chewing mouthparts. Males commonly make courtship sounds by rubbing together body parts, such as a ridge on their hind leg. Orthopterans undergo incomplete metamorphosis. Phasmida 2,600 Stick insects and leaf insects are exquisite mimics of plants. The eggs of some species even mimic seeds of the plants on which the Insects live. Their body is cylindrical or flattened dorsoventrally. They lack forewings but have fanlike hind wings. Their mouthparts are adapted for biting or chewing. Phthiraptera 2,400 Commonly called sucking lice, these insects spend their entire life as an ectoparasite feeding on the hair or feathers of a single host. Their legs, equipped with clawlike tarsi, are adapted for clinging to their hosts. They lack wings and have reduced eyes. Sucking lice undergo incomplete metamorphosis. Siphonaptera 2,400 Fleas are bloodsucking ectoparasites on birds and mammals. Their body is wingless and laterally compressed. Their legs are modified for clinging to their hosts and for long-distance jumping. They undergo complete metamorphosis. Thysanura 450 Silverfish are small, wingless insects with a flattened body and reduced eyes. They live in leaf litter or under bark. They can also infest buildings, where they can become pests. Trichoptera 7,100 The larvae of caddisflies live in streams, where they make houses from sand grains, wood fragments, or other material held to- gether by silk. Adults have two pairs of hairy wings and chewing or lapping mouthparts. They undergo complete metamorphosis. Swallowtail butterfly Dragonfly Katydid Stick insect Human Body louse Flea Silverfish Caddisfly ORDER APPROXIMATE NUMBER OF SPECIES MAIN CHARACTERISTICS EXAMPLE Figure 33.37
  • 86. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Crustaceans • While arachnids and insects thrive on land – Crustaceans, for the most part, have remained in marine and freshwater environments
  • 87. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Crustaceans, subphylum Crustacea – Typically have biramous, branched, appendages that are extensively specialized for feeding and locomotion
  • 88. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Decapods are all relatively large crustaceans – And include lobsters, crabs, crayfish, and shrimp Ghost crabs (genus Ocypode) live on sandy ocean beaches worldwide. Primarily nocturnal, they take shelter in burrows during the day. (a) Figure 33.38a
  • 89. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Planktonic crustaceans include many species of copepods – Which are among the most numerous of all animals Planktonic crustaceans known as krill are consumed in vast quantities by whales. (b) Figure 33.38b
  • 90. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Barnacles are a group of mostly sessile crustaceans – Whose cuticle is hardened into a shell The jointed appendages projecting from the shells of these barnacles capture organisms and organic particles suspended in the water. (c) Figure 33.38c
  • 91. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept 33.8: Echinoderms and chordates are deuterostomes • At first glance, sea stars and other echinoderms, phylum Echinodermata – May seem to have little in common with phylum Chordata, which includes the vertebrates
  • 92. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Chordates and echinoderms share characteristics of deuterostomes – Radial cleavage – Development of the coelom from the archenteron – Formation of the mouth at the end of the embryo opposite the blastopore
  • 93. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Echinoderms • Sea stars and most other echinoderms – Are slow-moving or sessile marine animals • A thin, bumpy or spiny skin – Covers an endoskeleton of hard calcareous plates
  • 94. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Unique to echinoderms is a water vascular system – A network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange Stomach Anus Ring canal Gonads Ampulla Podium Radial nerve Tube feet Spine Gills A short digestive tract runs from the mouth on the bottom of the central disk to the anus on top of the disk. The surface of a sea star is covered by spines that help defend against predators, as well as by small gills that provide gas exchange. Madreporite. Water can flow in or out of the water vascular system into the surrounding water through the madreporite. Branching from each radial canal are hundreds of hollow, muscular tube feet filled with fluid. Each tube foot consists of a bulb-like ampulla and suckered podium (foot portion). When the ampulla squeezes, it forces water into the podium and makes it expand. The podium then contacts the substrate. When the muscles in the wall of the podium contract, they force water back into the ampulla, making the podium shorten and bend. Radial canal. The water vascular system consists of a ring canal in the central disk and five radial canals, each running in a groove down the entire length of an arm. Digestive glands secrete digestive juices and aid in the absorption and storage of nutrients. Central disk. The central disk has a nerve ring and nerve cords radiating from the ring into the arms. Figure 33.39
  • 95. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The radial anatomy of many echinoderms – Evolved secondarily from the bilateral symmetry of ancestors
  • 96. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Living echinoderms are divided into six classes Table 33.6
  • 97. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Stars • Sea stars, class Asteroidea – Have multiple arms radiating from a central disk • The undersurfaces of the arms – Bear tube feet, each of which can act like a suction disk (a) A sea star (class Asteroidea)Figure 33.40a
  • 98. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Brittle Stars • Brittle stars have a distinct central disk – And long, flexible arms (b) A brittle star (class Ophiuroidea)Figure 33.40b
  • 99. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Urchins and Sand Dollars • Sea urchins and sand dollars have no arms – But they do have five rows of tube feet that function in movement (c) A sea urchin (class Echinoidea)Figure 33.40c
  • 100. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Lilies and Feather Stars • Sea lilies – Live attached to the substrate by a stalk
  • 101. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Cucumbers • Feather stars – Crawl about using their long, flexible arms (d) A feather star (class Crinoidea)Figure 33.40d
  • 102. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Cucumbers • Sea cucumbers – Upon first inspection do not look much like other echinoderms – Lack spines, and their endoskeleton is much reduced (e) A sea cucumber (class Holothuroidea)Figure 33.40e
  • 103. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sea Daisies • Sea daisies were discovered in 1986 – And only two species are known (f) A sea daisy (class Concentricycloidea)Figure 33.40f
  • 104. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chordates • Chordates – Phylum Chordata – Consists of two subphyla of invertebrates as well as the hagfishes and the vertebrates – Shares many features of embryonic development with echinoderms
  • 105. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • A summary of animal phyla Table 33.7