Ch 28 lecture_presentation
- 2. Phylum Porifera • Classified as Parazoa – Animals lacking tissues (and therefore organs) and a definite symmetry • 7000 marine species; 150 freshwater species • Among the most abundant animals in the deep ocean 2 Eumetazoa Protostomes Spiralia LophotrochozoaPlatyzoa Parazoa Acoelo- morpha Porifera Cnidaria Ctenophora Acoela Micrognathozoa Rotifera Cycliophora Platyhelminthes Brachiopoda Bryozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 3. • Most members lack symmetry • Larval sponges are free-swimming • Adults remain attached – “sessile” • Intracellular digestion only • Sexual and asexual reproduction • Embryo never undergoes gastrulation, so no true tissues 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Andrew J. Martinez/Photo Researchers, Inc. a.
- 4. 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Osculum Water Epidermal cell Amoebocyte Pore Choanocyte Spongin fiber Spicule Nucleus b. Collar Flagellum Choanocyte Ostium
- 5. Eumetazoa (i.e. everything except Parazoa) • Animals with true tissues that form after gastrulation • Embryos have distinct layers – Inner endoderm forms the “gastrodermis” – Outer ectoderm forms the “epidermis” and “nervous system” – Middle mesoderm (only in bilateral animals) forms the muscles • True body symmetry – Radial symmetry – Bilateral symmetry 5
- 6. Phylum Cnidaria • Most marine, few fresh water species • Diploblastic • Bodies have distinct tissues but no organs – No reproductive, circulatory, or excretory systems • No concentrated nervous system – “Latticework” or “net” of nerve cells – Respond to touch, gravity, light 6
- 7. • Cnidarians use stinging cells to capture prey – Some carry venom 7 Tentacles Mouth Gastrodermis Epidermis Nematocyte Trigger Undischarged nematocyst TubuleDischarged nematocyst Nematocyte with nematocyst Sensory cell Mesoglea Hydra3.3 mm (inset): © Roland Birke/Phototake Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 8. • 2 basic body forms Polyps – cylindrical and sessile Medusa – umbrella-shaped and free-living 8 Gastrovascular cavity Medusa Mouth Mesoglea Mouth Polyp Gastrodermis Epidermis Tentacles Epidermis Mesoglea Gastrovascular cavity Gastrodermis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 9. • Body plan has single opening (mouth) leading to gastrovascular cavity lined by gastrodermis – GVC is the site of extracellular digestion (key innovation), which is followed by phagocytosis – Most gas exchange occurs here – Waste discharge – Formation of gametes in many • 2 layers to body 1.Epidermis 2.Gastrodermis – Mesoglea between layers 9
- 10. • Gastrovascular space also serves as hydrostatic skeleton – Provides a rigid structure against which muscles can operate – Gives the animal shape • Many polyp species build an exoskeleton of chitin or calcium carbonate around themselves – Some build an internal skeleton 10
- 11. – Sea anemone – Coral animals – Box jellies – Star jellies – Jellies – Hydra, Portuguese man-of- war 11
- 12. Clades of Protostomes 12 Brachiopoda Platyhelminthes Cycliophora Rotifera Micrognathozoa Bryozoa Annelida Mollusca Nemertea Loricifera Kinorhyncha Nematoda Tardigrada Arthropoda Onychophora Chaetognatha Echinodermata Chordata Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Spiralia Ecdysozoa LophotrochozoaPlatyzoa
- 13. • Flatworms are ciliated, soft-bodied animals • Bodies are solid aside from an incomplete digestive cavity • Many species are parasitic; others are free-living (marine, freshwater, moist terrestrial) 13 Phylum Platyhelminthes - Flatworms 10 mm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Tom Adams/Visuals Unlimited
- 14. • 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 14
- 15. 15 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Eyespot Protruding pharynx Mouth Testis Oviduct Sperm duct Circular muscles Longitudinal muscles Parenchymal muscle Epidermis Nerve cord Intestine
- 16. 16 Reproductive System Excretory System Nervous System Intestine Nerve cord Testis Ovary Anterior cerebral ganglion Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 17. • Have an excretory and osmoregulatory system – Network of fine tubules runs through body – Metabolic wastes are excreted into the gut and eliminated through the mouth • Simple nervous system – Anterior cerebral ganglion and ventral nerve cords – Eyespot can distinguish light from dark • Reproduction – Most are hermaphroditic – Undergo sexual reproduction – Also have capacity for asexual regeneration 17
- 18. 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Metacercarial cysts in fish muscle Metacercariae are consumed by humans or other mammals Adult fluke Miracidium hatches after being eaten by snail Liver Bile duct Egg containing miracidium in feces (into water) Cercaria Sporocyst Redia 57 µm © Dwight R. Kuhn
- 19. • Tapeworms – Adult hangs onto inner wall of host intestine using scolex 19 500 µm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Dennis Kunkel/Phototake
- 20. • Most of tapeworm body is proglottids – Complete hermaphroditic unit, containing both male and female reproductive organs – Formed continuously • Beef tapeworm, Taenia saginata – Frequent human parasite – From eating uninspected rare beef 20 Scolex Hooks Sucker Proglottids Scolex attached to intestinal wall Uterus Proglottid Genital pore Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 21. Phylum Mollusca 21 • Second in diversity only to arthropods • Include snails, slugs, clams, octopuses and others • Some have a shell, some do not
- 22. Mollusk Body Plan • Mantle – Epidermal sheet – Secretes the 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 – Digestive, excretory, and reproductive organs are concentrated in a visceral mass 22
- 23. 23 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Radula Gut Lung Foot Gastropods Shell Antenna Radula Mantle Gut Shell Gill Foot Chitons
- 24. 24 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gut Gill Gut Gill Foot Mantle Shell Cephalopods Bivalves Siphons Siphon Eye ArmMantle cavity Adductor muscle Tentacle
- 25. • Shell – Protects against predators and adverse environments – Secreted by outer surface of mantle – Clearly not essential (some mollusks have a small or absent) – 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 25
- 26. • 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 • Gills used in filter feeding 26
- 27. 27 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Esophagus Radula tooth Muscles Mouth RadulaMouth 25 µm Bottom: © Eye of Science/Photo Researchers, Inc.
- 28. 28 Classes of Mollusks • Main Classes: 1. Polyplacophora – chitons 2. Gastropoda – limpets, snails, slugs 3. Bivalvia – clams, oysters, scallops 4. Cephalopoda – squids, octopuses, cuttlefishes, and chambered nautilus
- 29. 29 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
- 30. Class Gastropoda • Limpets, snails, slugs • Marine, freshwater, and terrestrial animals • Most have a single shell – some lost it • Heads typically have pairs of tentacles with eyes • Exhibit “torsion” – Mantle cavity and anus are moved from the posterior to the front 30
- 31. • Torsion should not be confused with coiling • Coiling – spiral winding of the shell 31
- 32. • Nudibranchs are active predators – Exposed gills – Many secrete distasteful chemicals – Some extract nematocysts from cnidarian prey and transfer them to their body surface 32
- 33. 33 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 – Adductor muscles counter hinge ligament • Water enters through inhalant siphon and exits through exhalant siphon
- 34. 34 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Inhalant siphon GillsMantle Intestine Foot Stomach Mouth Adductor muscle KidneyHeart Hinge Shell Exhalant siphon Gonad Anus
- 35. Class Cephalopoda • More than 600 strictly marine species • Active marine predators • The only mollusks with closed circulatory system • Foot has evolved into a series of arms equipped with suction cups • Largest relative brain sizes among invertebrates • Highly developed nervous system 35
- 36. Problem-solving by an octopus 36
- 37. • Living cephalopods lack external shell – 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 37
- 38. 38 Phylum Annelida – segmented worms • Body plan – Head has well-developed cerebral ganglion – Segments divided internally by septa – Closed circulatory system – Ventral nerve cord – Complete digestive tract
- 39. 39 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Dorsal blood vessel Septa Intestine Nephridium Mouth Pharynx Esophagus Clitellum Setae Ventral blood vessel Nerve cord Female gonads Male gonads Segments Hearts
- 40. • Leeches – Occur mostly in freshwater – Usually flattened dorsoventrally 40 Medicinal leech, Hirudo medicinalis
- 41. • Vinegar eels, Ascaris, heartworm, trichonella, and other roundworms • Members of this phylum are found everywhere – abundant and diverse • Marine, freshwater, parasites, free-living 41 181.1µm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Educational Images Ltd., Elmira, NY, USA. Used by Permission Phylum Nematoda - Roundworms
- 42. 42 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mouth Dorsal nerve cord Intestine Testis PharynxExcretory pore Muscle Pseudocoelom Excretory duct Intestine Testis Epidermis Ventral nerve cord Cuticle Genital pore Anus Spicules
- 43. • About 50 species cause human diseases – Hookworms – Common in southern U.S. – Produce anemia – Trichinella causes trichinosis – Forms cysts in muscles – Infection from eating undercooked meat (pork) 43 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 50 µm © Gary D. Gaugler/Photo Researchers, Inc.
- 44. • 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 44
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- 46. 46 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3.4% Crustaceans 36.2% Beetles 12.1% Flies 12.1% Butterflies, moths 10.3% Bees, wasps, ants 8.6% Other insects12.1% Other arthropods 5.2% Arachnids 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
- 47. Arthropod Morphology Part of arthropod success explained by: •Segmentation – Head, thorax, abdomen •Exoskeleton – Made of chitin and protein – Protects against water loss – Must undergo “ecdysis” – molting •Jointed appendages – Evolution has modified some into antennae, mouthparts, or wings – Can be extended and retracted 47
- 48. • Open circulatory system • Nervous system – Double chain of segmented ganglia – Ventral ganglia control most activities • Can eat, move, or copulate with brain removed 48 Head Thorax Abdomen Spiracles Tympanum Compound eye Ocellus Antennae Brain Aorta Stomach Ovary Heart Rectum Mouth Crop Gastric ceca Malpighian tubules Nerve ganglia a. b.
- 49. • Compound eyes are found in many arthropods – Composed of independent visual units called ommatidia • Other arthropods have simple eyes, or ocelli – May be in addition to compound eyes – Have single lenses – Distinguish light from darkness 49
- 50. 50 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ommatidium Corneal lens Crystalline cone Rhabdom Retinular cells Pigment cell Nervefiber Ommatidium Optic nerve Compound Eye
- 51. • Respiratory system – Many marine arthropods have gills – Some tiny arthropods have no structure for gas exchange – Terrestrial arthropods use tracheae – Many spiders use book lungs 51
- 52. Class Chelicerata • Spiders, ticks, mites, scorpions, daddy long-legs, horseshoe crabs, sea spiders • Most anterior appendages called chelicerae 52
- 53. Class Crustacea • Largely marine, some freshwater • Crabs, shrimps, lobsters, barnacles, crayfish, copepods, pill bugs, sand fleas • Gas exchange through gills or across cuticle 53
- 54. • Decapod crustaceans – Shrimps, lobsters, crabs, and crayfish – Have 10 feet (5 pairs of thoracic appendages) – Exoskeleton usually reinforced with CaCO3 – Cephalothorax covered by carapace 54
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- 56. Class Hexapoda • 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 at any one time 56
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- 58. 58 Order: Lepidoptera a. © Cleveland P. Hickman Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order: Homoptera b. © Valorie Hodgson/Visuals Unlimited Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. c. Order: Coleoptera © Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 59. 59 Order: Diptera d. © Kjell Sandved/Butterfl y Alphabet Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. e. Order: Orthoptera © Greg Johnston/Lonely Planet Images/Getty Images Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. f. Order: Isoptera © Nature’s Images/Photo Researchers, Inc.
- 60. External features •Three body regions 1. Head 2. Thorax has three segments, each with a pair of legs (=6 legs) 3. Abdomen •Most insects have compound eyes 60
- 61. 61 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.
- 62. • Insect life histories – Many insects undergo metamorphosis – Simple metamorphosis (grasshoppers) • Immature stages similar to adults – Complete metamorphosis (butterflies) • Immature larva are wormlike • A resting stage, pupa or chrysalis, precedes the final molt into adult form 62
- 63. Class Myriapoda • Centipedes – One pair of appendages per segment – Carnivorous – poison fangs • Millipedes – Two pairs of appendages per segment • Each segment is a tagma of 2 segments – Herbivores 63
- 64. Phylum Echinodermata • Exclusively marine • Deuterostomes with an endoskeleton • Pentaradial symmetry, but bilateral as larvae • Sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers 64
- 65. • Water-vascular system – Radially organized – Radial canal extends from ring canal into each body branch – Water enters through madreporite – Flows through stone canal to ring canal – Tube feet – may or may not have suckers • Ampulla – muscular sac at base • Used in movement, feeding, gas exchange 65
- 66. 66 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. Tube feetSkeletal plates Digestive glands Radial canal Ampulla Tube feet Gonad Stomach Anus Madreporite Water-vascular system b: © Frederic Pacorel/Getty Images
- 67. 67 Phylum Chordata • Chordates are deuterostome coelomates • Nearest relatives are echinoderms (the only other deuterostomes) • Fishes, amphibians, reptiles, birds, and mammals Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Spiralia Ecdysozoa Platyzoa Lophotrochozoa Micrognathozoa Rotifera Cycliophora Platyhelminthes Brachiopoda Bryozoa Annelida Mollusca Nemertea Loricifera Kinorhyncha Nematoda Tardigrada Arthropoda Onychophora Chaetognatha Echinodermata Chordata Deuter- ostomes
- 68. 4 Features 1. Dorsal nerve cord (not ventral like other animal phyla) 2. Notochord 3. Pharyngeal slits 4. Postanal tail 68 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hollow dorsal nerve cord Pharyngeal pouches Notochord Postanal tail
- 69. • All chordates have all four of these characteristics at some time in their lives • Other characteristics also distinguish chordates – Chordate muscles are arranged in segmented blocks called somites – Most chordates have an internal skeleton against which the muscles work 69 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 500 µm © Eric N. Olson, Ph.D./The University of Texas MD Anderson Cancer Center