Clades of Protostomes - Chapter 33 PDF

Clades of Protostomes All protostomes belong to either the Spiralia 2 or the Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Chaetognatha Chordata Onychophora Echinodermata Arthropoda Tardigrada Kinorhyncha Loricifera Nemertea Mollus...

Clades of Protostomes All protostomes belong to either the Spiralia 2 or the Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Chaetognatha Chordata Onychophora Echinodermata Arthropoda Tardigrada Kinorhyncha Loricifera Nemertea Mollusca Annelida Bryozoa Brachiopoda Platyhelminthes Nematoda Ecdysozoa Lophotrochozoa Cycliophora Rotifera All protostomes belong to either the Spiralia or the Ecdysozoa PROTOSTOMES Platyzoa Micrognathozoa Clades of Protostomes Spiralia Chapter 34 3 Ecdysozoa Contains animals that molt Exoskeleton - Hard external skeleton Two large groups Arthropods Nematodes 1 2 3 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lophophore tentacles Apical tuft of cilia Spiralia Band of cilia Mouth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Embryos develop using spiral cleavage Most live in water Protostomes Spiralia Chordata Echinodermata Chaetognatha Onychophora Arthropoda Tardigrada Nematoda Kinorhyncha Ecdysozoa Loricifera Move using cilia or contractions of the body musculature Two clades Nemertea Flatworms Mollusca 7 Lophotrochozoa Annelida Trochophore (a) and lophophore (b) Platyzoa Bryozoa Flatworms b. Brachiopoda a. Platyhelminthes Trunk Cycliophora Anus Rotifera Platyzoans—PhylumPlatyzoans—Phylum Platyhelminthes Platyhelminthes Mouth Gut Micrognathozoa Anus Stomach Flatworms are ciliated, Flatworms are ciliated, soft-bodied animals Bodies are solid aside from an incomplete soft-bodied animals digestive cavity Bodies are solid aside Many species are parasitic Others are free-living from an incomplete digestive cavity – Marine, freshwater, moist terrestrial Many species are parasitic Others are free-living Platyzoans Most prominent group is the flatworms Simple bodies with no circulatory or respiratory systems, but complex reproductive system Includes marine and freshwater planarians and parasitic flukes and tapeworms Lophotrochozoa Two characteristics define members of this group Trochophore—a free-living larva Lophophore—a horseshoe-shaped crown of ciliated tentacles surrounds the mouth used in filter-feeding 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3 Marine, freshwater, moist terrestrial 10 mm © Tom Adams/Visuals Unlimited 10 4 5 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Only one opening to digestive cavity Muscular contractions in the pharynx allows food to be ingested and torn into small bits Lack circulatory system Diffusion for gas transport Gut functions in digestion and food distribution Some particles digested extracellularly Cells engulf particles by phagocytosis Tapeworms (parasitic flatworms) lack digestive systems – absorb food directly through body walls Have an excretory and osmoregulatory system Protruding pharynx Eyespot Mouth Network of fine tubules runs through body Flame cells located on the side branches Flagella move water and excretory substances into the tubules and then to pores located between the epidermal cells through which the liquid is expelled Metabolic wastes are excreted into the gut and eliminated through the mouth Circular muscles Testis Oviduct Longitudinal muscles Parenchymal muscle Sperm duct Nerve cord Intestine Epidermis Nervous System Anterior cerebral ganglion 12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Excretory System Reproductive System Ovary Intestine Testis Simple nervous system Anterior cerebral ganglion and nerve cords Eyespot can distinguish light from dark Reproduction Most are hermaphroditic Undergo sexual reproduction Also have capacity for asexual regeneration Nerve cord 13 5 6 1 Miracidium hatches after being eaten by snail A Egg containin miracidium in (into water) Liver Sporocyst 8 Redia Cercaria © Dwight R. Kuhn Bile duct Metacercariae are consumed by humans or other mammals Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. One of most important trematodes to human health are blood flukes Schistosoma 57 !m 2 major groups of flatworms Metacercarial cysts in fish muscle 7 Free-living Turbellaria Afflict 5% of world’s population About 800,000 people die each Probably not monophyletic Dugesia – common planarian in bio labs year from schistosomiasis or bilharzia Fertilized egg must break through the wall of the blood vessels in intestine or the urinary bladder to get out © The Natural History Museum/Alamy Parasitic Neodermata Trematoda – flukes Attach within host body by suckers, anchors, or hooks Life cycle may have 2 or more hosts Clonorchis sinensis, oriental liver fluke Cercomeromorpha – tapeworms Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cercomeromorpha – tapeworms Adult hangs onto inner wall of host intestine using scolex 500 !m © Dennis Kunkel/Phototake 7 8 Cercomeromorpha – tapeworms – Adult hangs onto inner wall of host intestine using scolex 19 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mouth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hooks Corona Rotifera Uterus Scolex attached to intestinal wall Genital pore Brain Pharynx Platyzoans Bilaterally symmetrical, unsegmented pseudocoelomates Highly developed internal organs Corona – “wheel animals” Sucker Proglottids Proglottid Digestive tract Anus 14.5!m Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Scolex Most of of tapeworm body is proglottids Most tapeworm body is proglottids Complete hermaphroditic unit, containing both male and female – Complete hermaphroditic unit, containing both male and female reproductive organs reproductive organs Formed continuously – Formed continuously Beef tapeworm, Taenia saginata Beef tapeworm, Taenia saginata Frequent human parasite From eating uninspected rare beef – Frequent human parasite – From eating uninspected rare beef © T.E. Adams/Visuals Unlimited Conspicuous ring of cilia at anterior end Used for locomotion and sweeping food into the mouth Brain Pharynx Digestive tract Anus Toe 20 © T.E. Adams/Visuals Unlimited 12 Lophotrochozoans—Phylum Mollusca Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Range in size from microscopic to huge Giant clams may weigh 270 kg Evolved in the oceans, and most groups have remained there Important source of human food Economically significant in other ways Chordata Echinodermata Chaetognatha Onychophora Arthropoda Nematoda Tardigrada Loricifera Nemertea Mollusca Annelida Bryozoa Kinorhyncha Ecdysozoa Lophotrochozoa Platyhelminthe s Brachiopoda Platyzoa Cycliophora Second in diversity only to arthropods Include snails, slugs, clams, octopuses and others Some have a shell, some do not Spiralia Micrognathozoa Rotifera Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pearls are produced in oysters Mother-of-pearl is produced in the shells of abalone Pests – Zebra mussel (Dreissena polymorpha) b. b. 11 c. 22 10 11 a. 22 Corona 14.5!m 9 a. Toe Mouth 12 d. 24 a: © Marty Snyderman/Visuals Unlimited; b: © Alex Kerstitch/Visuals Unlimited; c: © Douglas Faulkner/Photo Researchers, Inc.; d: © agefotostock/SuperStock c. d. 24 a: © Marty Snyderman/Visuals Unlimited; b: © Alex Kerstitch/Visuals Unlimited; c: © Douglas Faulkner/Photo Researchers, Inc.; d: © agefotostock/SuperStock 2 13 14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusk Body Plan Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chitons Mantle Thick epidermal sheet Bounds mantle cavity Secrete shell (if there is one) Foot Primary means of locomotion for many Divided into arms or tentacles in cephalopods Internal organs Coelom is highly reduced Bivalves Mantle Shell Gut Gut Adductor muscle Shell Gill Siphons Foot Radula Gill Mantle Foot Gastropods Cephalopods Shell Gut Lung Gut Limited to small spaces around the excretory organs, heart, and part of the intestine Digestive, excretory, and reproductive organs are concentrated in a visceral mass Ctenidia – gills in aquatic mollusks Foot Tentacle Siphon Antenna Radula Mantle cavity Gill Arm Eye 29 28 Also filter food in most bivalves 13 14 15 16 Shell Protects against predators and adverse environments Secreted by outer surface of mantle Clearly not essential – repeated loss or reduction Typical shell has 2 layers of calcium carbonate Internal layer may be mother-of-pearl or nacre Pearls are formed by coating foreign object with nacre to reduce irritation Consist of cilia-lined openings called nephrostomes Tube to excretory pore to mantle cavity Circulatory system Open circulatory system Hemolymph sloshes around hemocoel 3-chambered heart Cephalopods have a closed circulatory system Esophagus Radula tooth Muscles Mouth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Radula Characteristic of most mollusks Rasping, tonguelike structure used in feeding Used to scrape up algae In predatory gastropods, modified to drill through clam shells In Conus snails, modifies into harpoon with venom gland Bivalves do not have a radula Nitrogenous waste removal – nephridia Mouth Radula Gills used in filter feeding Bottom: © Eye of Science/Photo Researchers, Inc. 25 !m 32 15 16 17 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusk Trochophore Larva Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Trochophore Mollusk Reproduction Trochophore Classes of Mollusks Mollusk Trochophore Larva – Free-swimming larval –stage Free-swimming Most mollusks are gonochoric larval A few are hermaphroditic stage There are 7 or 8 recognized classes Veliger Some oysters change sex Veliger – Second free Most engage in external fertilization Gastropods have internal fertilization –swimming Second freelarval stage 2. a. Mollusk zygote undergoes spiral cleavage swimming larval stage – Only in bivalves and –most Only marine in bivalves and snails Trochophore most marine snails Free-swimming larval stage © Demian Koop, Kathryn Green, Daniel J. Jackson Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. © Demian Koop,Veliger Kathryn Green,Larva Daniel J. Jackson Gastropod Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gastropod Veliger Larva Both forms drift Both forms widely in thedrift ocean Second free-swimming larval stage widely in the ocean Only in bivalves and most marine snails Veliger Both forms drift widely in the ocean 35 b. 17 Polyplacophora – chitons Gastropoda – limpets, snails, slugs 3. Bivalvia – clams, oysters, scallops 4. Cephalopoda – squids, octopuses, cuttlefishes, and chambered nautilus 1. b. © Kjell Sandved/Butterfly Alphabet © Kjell Sandved/Butterfly Alphabet 35 18 3 19 20 Class Gastropoda Class Polyplacophora (Chitons) Marine mollusks that have oval bodies 8 overlapping dorsal calcareous plates Body is not segmented under the plates Most chitons are grazing herbivores Limpets, snails, slugs A primarily marine group – some freshwater, and only terrestrial mollusks Most have a single shell – some lost it Heads typically have pairs of tentacles with eyes Torsion 19 Unique among animals Mantle cavity and anus are moved from the posterior to the front Torsion should not be confused with coiling Coiling – spiral winding of the shell 20 21 22 Class Bivalvia (Bivalves) Includes clams, scallops, mussels, oysters, and others Most marine, some freshwater No radula or distinct head Have 2 shells (valves) hinged together Nudibranchs are active predators Exposed gills Many secrete distasteful chemicals Some extract nematocysts from cnidarian prey and transfer them to their body surface Adductor muscles counter hinge ligament Water enters through inhalant siphon and exits through exhalant siphon Copyright © The McGraw-Hill Companies, Inc. 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Heart Shell Hinge Kidney Adductor muscle Stomach Gonad Mouth Anus Intestine Exhalant siphon Inhalant siphon Foot Gills Mantle 42 21 22 23 24 Class Cephalopoda More than 600 strictly marine species Active marine predators Only mollusk with closed circulatory system Foot has evolved into a series of arms equipped with suction cups Problem-solving by an octopus Beak-like jaws, toxic saliva Living cephalopods lack external shell Largest relative brain sizes among invertebrates Highly developed nervous system Problem-solving by an octopus Except chambered nautilus Squid and cuttlefish have internal shells Jet propulsion using siphon Ink can be ejected from siphon Chromatophores allow for changing skin color for camouflage or communication 44 23 24 4 25 26 Lophotrochozoans—Nemertea Lophotrochozoans—Nemertea About 900 species of cylindrical to flattened very Protostomes Spiralia Platyzoa Ecdysozoa Chordata Onychophora Echinodermata Arthropoda Chaetognatha Tardigrada Nematoda Kinorhyncha Loricifera Nemertea Mollusca Annelida Bryozoa Brachiopoda Lophotrochozoa Platyhelminthes Rotifera Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cycliophora long worms cylindrical to flattened very long worms Most are marine; a few species live in fresh water and humid terrestrial habitats Lineus longissimus has been reported to measure 60 m in length – the longest animal known! Body plan resembles a flatworm Has a complete gut Rhynchocoel – fluid filled coleomic cavity Micrognathozoa About 900 species of Gonochoric with sexual reproduction Belong to lophotrochozoans because 46 25 Asexual reproduction through fragmentation Blood flows entirely in vessels Rhynchocoel 26 27 28 Lophotrochozoans Phylum Annelida Body plan Head has well-developed cerebral ganglion Sensory organs in ringlike segments Many species have eyes Segments divided internally by septa Each segment has a pair of excretory organs, a ganglion, and locomotory structure Closed circulatory system Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Setae Mouth Pharynx Segments Protostomes Spiralia Chordata Echinodermata Chaetognatha Onychophora Arthropoda Tardigrada Loricifera Nemertea Mollusca Annelida Bryozoa Nematoda Ecdysozoa Lophotrochozoa Brachiopoda Cycliophora Rotifera Micrognathozoa Platyzoa Kinorhyncha Platyhelminthes Segmented worms Body built of repeated units Allows for specialization May not be monophyletic Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 27 Dorsal blood vessel Male gonads Female gonads Septa Nerve cord Ventral blood vessel Intestine Nephridium 51 Ventral nerve cord 28 29 30 Each part of digestive tract specialized for different function Locomotion Coelomic fluid creates a hydrostatic skeleton Alternating muscle contractions allows complex movements Chaetae – bristles of chitin found in most groups Class Polychaeta (Polychaetes) Include clamworms, scaleworms, lugworms, sea mice, tubeworms Have paired parapodia on most segments Closed circulatory system Gas exchange by diffusion across body surfaces Used in locomotion or gas exchange Chaetae on parapodia Most gonochoric External fertilization Trochophore larva Deep-sea tubeworm Riftia Adults gutless Sulfur-oxidizing bacteria synthesize organic compounds used by worm Found near hydrothermal vents Excretory system – nephridia similar to mollusks Roughly 12,000 described species of annelids occur in many habitats 2 classes 1. Class Polychaeta - Monophyly not well established 2. Class Clitella – Oligochaeta and Hirudinea 29 Brain Esophagus Hearts Clitellum 30 5 31 32 Class Clitellata Head not well differentiated No parapodia Include two phyla of mostly marine animals Both characterized by lophophore Bryozoa and Brachiopoda Few chaetae project from body wall Hermaphroditic but cross-fertilize Clitellum secretes mucus cocoon Circular or U-shaped ridge around the mouth with 1–2 rows of ciliated tentacles Protostomes Functions in gas exchange and feeding Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spiralia Platyzoa Ecdysozoa Chordata Echinodermata Chaetognatha Onychophora Arthropoda Tardigrada Nematoda Kinorhyncha Loricifera Nemertea Mollusca Lophotrochozoa Annelida Phylogeny a puzzle Bryozoa May be convergent evolution Brachiopoda Medicinal leech, Hirudo medicinalis Leeches mostly in freshwater / Usually flattened dorsoventrally Hermaphroditic and cross-fertilization Clitellum develops only during breeding season Coleom reduced, not divided into segments Suckers at both ends of body No chaetae (except for one species) Some eat detritus, others suck blood Platyhelminthes Earthworms Rotifera The Lophophorates Cycliophora Clitellum found in all members Micrognathozoa 59 31 32 33 34 Phylum Bryozoa Phylum Brachiopoda Also called Ectoprocta or “moss animals” Bryozoans are small and live in colonies Brachiopods or lamp shells Have two calcified shells Their anus opens near their mouth Individuals secrete a tiny chitinous chamber called a zoecium attached to substrate May deposit calcium carbonate (formed reefs in past) Asexual reproduction occurs frequently by budding Dorsal and ventral (not lateral as in bivalves) Lophophore lies on the body, between the shells Phoronids were once a separate phylum Each individual secretes a chitinous tube Extends lophophore to feed Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spiral portion of lophophore Mouth Coelom Adductor muscle Intestine Mantle Later alarm of lophophore Ventral (pedicle) valve Nephridium Stomach Digestive gland Pedicle b. a. 33 Dorsal (brachial) valve Gonad 34 B: © Fred Bavendam/Minden Pictures Brachiopods 63 35 36 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Spiralia Mouth Anus Nephridium Ecdysozoa Chordata Echinodermata Chaetognatha Onychophora Arthropoda Tardigrada Nematoda Loricifera Nemertea Mollusca Annelida Bryozoa Lophotrochozoa Brachiopoda Platyhelminthes Vinegar eels, eelworms, and other roundworms Members of this phylum are found everywhere – abundant and diverse Marine, freshwater, parasites, freeliving Rotifera Cycliophora A phoronid lives in a chitinous tube that the animal secretes. The lophophore consists of two horseshoe-shaped ridges of tentacles and can be withdrawn into the tube when the animal is disturbed. Tentacles of lophophore Micrognathozoa Platyzoa Kinorhyncha Lophophore 65 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Body wall Intestine Gonad 181.1µm © Educational Images Ltd., Elmira, NY, USA. Used by Permission 35 36 6 37 38 Bilaterally symmetrical and unsegmented Covered by a flexible, thick cuticle that is molted as they grow Digestive system well developed 38 Stylets – piercing organs near mouth Pharynx – creates sucking action Anus Eutely Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mouth Lifestyles Excretory pore Pharynx Testis Dorsal nerve cord Muscle Intestine Sexual reproduction Anus Pseudocoelom Spicules Excretory duct Intestine Testis Epidermis Ventral nerve cord Cuticle Genital pore Most gonochoric Sexual dimorphism – male smaller with hooked end Adults consist of a fixed number of cells Caenorhabditis elegans has only 959 cells Important in genetic and developmental studies Many are active hunters, preying on protists and other small animals Others are parasites of plants Still others live within the bodies of larger animals Largest known nematode, which can attain a length of 9 m, parasitizes the placenta of sperm whales Internal fertilization Indirect development – egg, larva, adult 37 38 40 Arthropoda 39 Arthropoda About 50 species cause human diseases Hookworms Common in southern U.S. Produce anemia Protostomes Spiralia Platyzoa By far the most successful animals Well over 1,000,000 species (2/3 of all named species) Arthropods affect all aspects of human life Divided into four extant classes Chelicerata /Crustacea / Hexapoda/ Myriapoda Ecdysozoa Lophotrochozoa Pinworms, Enterobius vermicularis Infects 30% of children in U.S. Causes itching of the anus Ascaris lumbricoides – intestinal Infects 1 in 6 worldwide Adult female can be 30 cm long Rare in areas with modern plumbing Onychophora Chordata Arthropoda Echinodermata Tardigrada Chaetognatha Kinorhyncha Nematoda Mollusca Annelida Loricifera Nemertea Bryozoa Brachiopoda Platyhelminthes Rotifera Cycliophora Micrognathozoa Trichinella causes trichinosis Forms cysts in muscles Infection from eating undercooked meat Serious tropical Filariasis Elephantiasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 73 roundworm nematode diseases 39 40 75 41 42 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Arthropod Morphology 12.1% Flies 12.1% Butterflies, moths 36.2% Beetles 12.1% Other arthropods Part of arthropod success explained by 1.Segmentation 10.3% Bees, wasps, ants 8.6% Other insects Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. In some classes specialized into tagmata Head, thorax, abdomen Head and thorax may be fused into cephalothorax or prosoma 3.4% Crustaceans 5.2% Arachnids 2.Exoskeleton Made of chitin and protein Protects against water loss Arthropods are a successful group About two-thirds of all named species are arthropods. About 80% of all arthropods are insects, and about half of the named species of insects are beetles 41 Must undergo ecdysis – molting 3.Jointed Air sac Thorax Malpighian tubules Head Compound eye Abdomen Antenna Rectum Sting Mouth parts Spiracles Midgut Poison sac appendages May be modified into antennae, mouthparts, or 3. Jointed appendages wings May be modified into antennae, mouthparts, or wings Can be extended and retracted Can be extended and retracted 78 42 7 43 Open circulatory system Nervous system Double chain of segmented ganglia Ventral ganglia control most activities 44 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Head Thorax Abdomen Compound eyes are found in many arthropods Antennae Ocellus Other arthropods have simple eyes, or ocelli Compound eye Spiracles Tympanum Composed of independent visual units called ommatidia May be in addition to compound eyes Have single lenses Distinguish light from darkness Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ommatidium Corneal lens a. Brain Aorta Stomach Ovary Heart Crystalline cone Compound Eye Rectum Can eat, move, or copulate with brain removed Rhabdom Crop Mouth Gastric ceca Malpighian tubules Retinular cells Nerve ganglia Pigment cell b. Ommatidium Nervefiber Optic nerve 81 43 44 45 Respiratory system Brain Many marine arthropods have gills Some tiny arthropods lack any structure for gas exchange Terrestrial arthropods use tracheae Branch into tracheoles in direct contact with cells Connected to the Tracheoles exterior by spiracles Stomach Ovary Crop Gastric ceca Heart Malpighian tubules Rectum Nerve ganglia b. Excretory system Trachea Valves control water loss Many spiders use book lungs Aorta Mouth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 46 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spiracles Eliminates nitrogenous wastes as concentrated uric acid or guanine Spiracles Leaflike plates In aquatic arthropods much of the waste diffuses out of gills Terrestrial insects and some others use Malpighian tubules Efficient conservation of water 83 45 46 47 48 Order Araneae (spiders) Class Chelicerata Many spiders catch their prey in silk webs Anterior prosoma bearing all appendages Silk protein forced out of spinnerets found on the posterior of the abdomen Other spiders actively hunt their prey All spiders have poison Black Widow Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brown Recluse glands with channels through their chelicerae Pedipalps and 4 pairs of walking legs About 35,000 species Particularly important as predators May function as fangs or pincers Body divided into 2 tagmata Spiders, ticks, mites, scorpions, daddy long-legs, horseshoe crabs, sea spiders Most anterior appendages called chelicerae Posterior opisthosoma contains reproductive organs a. b. a: © National Geographic/Getty Images; b: © S. Camazine/K. Visscher/Photo Researchers, Inc. 47 87 48 8 49 50 Class Crustacea Order Acari (mites and ticks) Most diverse of the chelicerates Predators and parasites Most mites are small Cephalothorax and abdomen are fused into an unsegmented ovoid body Largely marine, some freshwater Crabs, shrimps, lobsters, barnacles, crayfish, copepods, pill bugs, sand fleas Have three tagmata Ticks are larger Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Blood-suckers Abdomen Cephalothorax Can carry many diseases Cephalon and thorax fused to form a cephalothorax 2 pairs of antennae, 3 pairs of appendages for chewing, and various pairs of legs Rocky Mountain spotted fever, Lyme disease Most appendages are biramous Gas exchange through gills or across cuticle Cheliped Walking legs Swimmerets Antenna Telson Uropod Antennule Eye 49 50 90 51 All crustaceans but barnacles are gonochoric Many kinds of copulation Nauplius stage 52 Order Cirripedia (Barnacles) Sessile as adults Several stages before maturity Evidence of common ancestor for diverse group Captures food with feathery legs Hermaphroditic Longest penis in the animal kingdom relative to size Decapod crustaceans Gills Shrimps, lobsters, crabs, and crayfish Have 10 feet – 5 pairs of thoracic appendages Exoskeleton usually enforced with CaCO 3 Cephalothorax covered by carapace Lobsters and crayfish Swimmerets used in reproduction and swimming Uropods paddle on either side of telson Crab has small abdomen held under carapace 51 52 53 Class Hexapoda 54 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order: Diptera Insects are by far the largest group of animals Number of species and number of individuals More than half of all named animal species Approximately one billion billions (1018) insects are alive Order: Lepidoptera at any one time Order: Homoptera Order: Orthoptera d. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Kjell Sandved/Butterfl y Alphabet Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order: Lepidoptera Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order: Isoptera Order: Homoptera a. b. e. © Valorie Hodgson/Visuals Unlimited © Cleveland P. Hickman Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. © Greg Johnston/Lonely Planet Images/Getty Images 98 f. © Nature s Images/Photo Researchers, Inc. Order:b.Coleoptera © Valorie Hodgson/Visuals Unlimited © Cleveland P. Hickman Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order: Coleoptera c. 97 © Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org c. 53 © Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org 97 54 9 55 56 External features Three body regions Internal organization Head 2. Thorax has three segments, each with a pair of legs May have one or two pairs of wings – outgrowths of body wall 3. Abdomen 1. Most insects have compound eyes Form bellows to force air deep into body Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. spiracles through which air enters the tracheal system a. Mosquito - piercing b. Butterfly - sucking Some parasitic or aquatic forms have permanently closed spiracles – use diffusion The aquatic larvae of mosquitoes are quite active. They breathe through tubes at the surface of the water, as shown here. Covering the water with a thin film of oil suffocates them. c. Fly - sopping Insect mouthparts all have the same basic structure Insect mouthparts all have the same basic Modifications reflect feeding habits structure Modifications reflect feeding habits 55 The digestive tract is a tube Digestion takes place in stomach (midgut) Excretion tales place through Malpighian tubules Winged insects have dilated tracheae forming air sacs 56 100 57 58 Sensory receptors Class Myriapoda Sensory setae are hairlike structures Detect chemical and mechanical signals Tympanum – a thin membrane associated with tracheal air sacs Detect sound May also use sensory hairs to detect sound Pheromones also used for communication Mating signals, trail markers Insect life histories Immature larva are wormlike A resting stage, pupa or chrysalis, precedes the final molt into adult form Head regions followed by numerous segments Gonochoric, internal fertilization, lay eggs 57 Two pairs of appendages per segment Each segment is a tagma of 2 segments Herbivores Complex glands produce bad-smelling fluid in defense Simple metamorphosis (grasshoppers) Immature stages similar to adults Complete metamorphosis (butterflies) One pair of appendages per segment Carnivorous – poison fangs Millipedes (subclass Diplopoda) Many insects undergo metamorphosis Centipedes (subclass Chilopoda) Young add segments as they grow 58 10