Invertebrates. Domain Eukarya Kingdom Animalia The Metazoans

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1 Invertebrates Domain Eukarya Kingdom Animalia The Metazoans

2 Evoln of Animals Animals of Kingdom Animalia are multicellular euakaryotic heterotrophs that ingest their food Animals have the diploid life cycle and usually reproduce sexually

3 Muscle and Nerve Tissues characterize animals Enables animals to 1) search actively for their food and 2) prey on other organisms

4 Animals are monophyletic Both invertebrates and vertebrates can trace their ancestry to the same ancestor Adult vertebrates have a spinal cord (backbone) Invertebrates do not have a backbone

5 Ancestry of Animals The colonial flagellate hypothesis states that animals are descended from an ancestor that resembled a hollow spherical colony of flagellated cells

6 Colonial flagellate hypothesis implies that radial symmetry preceded bilateral symmetry in the history of animals

7 Any longitudinal cut produces two identical halves Radial Symmetry

8 Bilateral Symmetry Only one longitudinal cut yields two identical halves

9 Remember the Choanoflagellate?

10 The choanoflagellates (collared flagellates) resemble the last unicellular ancestor of living animals, and molecular data illustrates that they are the closest living relatives of animals As water moves through the microvilli, they engulf bacteria and debris from the water

11 Phylogenetic Tree of Animals -Cladogram- Based on molecular and morphological data The more closely related two organisms are, the more rrna nucleotide sequences they will have in common It s all genetic and chemical

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14 Morphological Data Asymmetry Radial Symmetry Bilateral Symmetry

15 Asymmetry There is no particular body shape (e.g., sponges)

16 Radial Symmetry Body parts arranged around an axis, like spokes of a wheel (e.g., starfish) May be sessile attached to a substrate or less motile Enables the animal to reach out in all directions from one center

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18 Bilateral Symmetry Body plan having a right and left, or complementary halves Only one longitudinal cut down the center produces mirror halves Tend to be active Have anterior (front) and posterior (back) ends Development of head to localize the brain and sensory organs at the anterior end (Cephalization)

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21 Embryonic Development The first three tissue layers are called germ layers. They give rise to the organs and organ systems of complex animals

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23 Diploblastic Animals with two tissue layers (ectoderm and endoderm) as embryos

24 Triploblastic Animals that develop further and have all three tissue layers (ectoderm, mesoderm, and endoderm) as embryos Can be further divided into protostomes or deuterostomes A coelom forms by the splitting of the mesoderm.

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26 Protostomes exhibit the following events during embryological development Spiral cleavage in which the cells divide w/o an in size Fate of cells is fixed each contributes to development in only one particular way blastopore is associated w/ the mouth A coelom forms by splitting of the mesoderm, which has arisen from cells near the blastopore

27 A body cavity Coelom Lies between the gut and body wall and has a lining (the peritoneum) derived from the mesoderm Organs that developed w/in this cavity are cushioned and protected

28 Deuterostomes exhibit the following events during embryological development Radial cleavage - the new daughter cells sit atop the previous cells Fate of cells is indeterminate Blastopore is associated with the anus, mouth appears later Coelom forms by the fusion of mesodermal pouches from the primitive gut

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32 Body Cavities - Acoelomate epidermis gut cavity no body cavity; region between gut and body wall packed with organs Fig. 25-6, p.406

33 Body Cavities - Pseudocoelomate epidermis gut cavity unlined body cavity (pseudocoel) around gut Fig. 25-6, p.406

34 Body Cavities - Coelom gut cavity lined body cavity (coelom) peritoneum Fig. 25-6, p.406

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37 Phylum Porifera The Sponges

38 No symmetry No tissues Cells line all body surfaces but don t form distinct tissues No organs Aquatic Sessile Filter feeders water enters through tiny pores and exits through one or more large openings

39 Collar cells trap food Cells engulf bacteria or other organic debris Collar cells release some of it to amoeba-like cells that process food and carry out other tasks that benefit the sponge

40 Water injected with fluorescien dye to watch the filtering process

41 Sponge Skeleton All sponges have fibers made of spongin a protein that gives the sponge its flexibility The endoskeleton contains spicules tiny needle shaped structures with 1-6 rays

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43 Sponge Predators Sea Slugs Very few b/c of spicules and production of foul smelling and toxic substances

44 Asexual Reproduction - Budding Small buds or pieces break away and grow into new sponges Can produce large colonies Fragmentation Production of Gemmules - encapsulated amoebocytes

45 Sexual Reproduction Eggs and sperm are released into the central cavity Zygote develops into a ciliated larva free living, sexually immature stage of animal development Larvae are flagellated, can swim briefly until settle in suitable substrate

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47 water out glasslike structural elements central cavity amoeboid cell pore semifluid matrix flattened surface cells water in flagellum microvilli nucleus Stepped Art Fig , p.409

48 Fig. 25-9d, p.408

49 The Jellies

50 Phylum Ctenophora The Comb Jellies The largest animals propelled by beating cilia Range in size from a few cm to 1.5 m in length Most of their body is jelly-like material called mesoglea Long tentacles covered with sticky filaments or an entire body covered by sticky mucus captures prey

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52 Cnidarians Tubular or bell-shaped Can be marine, freshwater or brackish forms Gastrovascular cavity digests food, circulates nutrients and serves as supportive hydrostatic skeleton Phylum Cnidaria

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54 Phylum Cnidaria Only animals that produce nematocysts Nerve net Hydrostatic skeleton Saclike gut capsule s lid at free surface of epidermal cell trigger barbed thread inside capsule nematocyst Fig , p.410

55 Have cnidocytes specialized cells containing nematocysts The nematocyst is a fluid-filled capsule containing a long, spirally coiled hollow thread When the trigger of cnidocyte is touched, the nematocyst is discharged Some threads merely trap prey or predators; others have spines that penetrate and inject paralyzing toxins

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61 What can the nematocysts do to humans?

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63 Two Main Body Plans outer epithelium (epidermis) Polyp mesoglea (matrix) Medusa inner epithelium (gastrodermis) Fig , p.410

64 Polyp is vase-shaped Mouth is upward Sessile Produces the medusae Medusa is bell-shaped Mouth is downward Has more mesoglea Tentacles found around margin of bell Motile Produces eggs and sperm

65 Class Phylum

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67 Class Anthozoa Sea Anemones Solitary polyps Upward turned oral disk contains mouth surrounded by hollow tentacles containing nematocysts

68 Class Anthozoa - Corals Resemble sea anemones encased in CaCO 3 Responsible for coral reefs by slow accumulation of limestone

69 Class Hydrozoa - Hydra Dominant polyp stage Portuguese Man of War is colony of polyps Original polyp becomes the gas-filled float

70 Nerve Net of Hydra

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72 Class Scyphozoa True Jellies Helmet Jelly

73 Class Cubozoa Box Jellies

74 The Flatworms The Simplest Organ Systems

75 Phylum Platyhelminthes Bilateral Symmetry Moderate cephalization Triploblastic Possess several distinct organs, organ systems and true muscles Possess an incomplete digestive tract only one opening No coelom

76 Class Turbellaria Marine or freshwater and moist terrestrial habitats

77 Planarians Carnivorous eat small animals and carrion Breathe by diffusion through skin Flattened body places all cells close to water Flame cells excretory apparatus fxn to maintain water balance Ammonia wastes diffuse from cells to water Move by means of cilia on ventral surface to glide along film of mucus

78 Pharynx sucks up food and expels wastes

79 Reproduce asexually by transverse fission Mid-body constriction separates the parent into two halves, each of which regenerates the missing portion

80 Reproduces sexually by crossfertilization of hermaphroditic forms

81 Muscular contractions produce undulations which allow some to swim Eyespots on head detect light Pair of lateral auricles detect environment Rudimentary brain (ganglia) capable of simple learning

82 Class Trematoda PARASITIC feed on a host Cause weight loss BLOOD FLUKES and LIVER FLUKES Suckers present for attaching to host internal organs Majority are hermaphroditic

83 Life cycle of Schistosoma japonicum Infects 200 million people/year Human is the definitive (1 ) host where the mature parasite lives Snail is the intermediate (2 ) host where the immature stage lives

84 TAPEWORMS Class Cestoda Parasites of vertebrate digestive systems Scolex head armed with suckers and/or hooks that help maintain position by attaching to intestinal lining

85 Proglottids long ribbon of units located behind scolex Filled with reproductive organs No digestive system

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87 Life Cycle Mature proglottids fill with eggs, are released from posterior end of worm, pass from body with feces Eggs are eaten by intermediate host and larva develops, usually in muscle tissue Definitive host becomes infected when it eats an intermediate host containing the larvae *Cook your beef and pork WELL DONE

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91 Life cycle of the beef tapeworm Taenia saginata. Can grow to be 25 meters long.

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93 The Annelids Segmented worms

94 Phylum Annelida True coelom well-developed and fluid-filled serves as hydrostatic skeleton, permits development of complex organ systems, protects internal structures, permits internal organs to fxn separately from the body wall muscles Segmented (repeated body parts) provides for specialization of diff body regions

95 Class Oligochaeta / Clitellata The earthworms - (scavengers) Feed on soil and detritus decaying org matter Aerate the soil important to farmers Few bristles (setae) per segment used for traction while crawling and burrowing

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99 Complete digestive system divided into parts Each part specialized for a specific fxn in digestion Pharynx esophagus crop gizzard intestine *Excretory system found in each segment

100 Closed Circulatory System Hgb present in blood cells Dorsal and ventral longitudinal vessels connected by pairs of vessels 5 pairs of hearts circle the esophagus gas exchange thru skin

101 Nervous System Pair of cerebral ganglia (rudimentary brain) lie above pharynx

102 Reproduction hermaphroditic Worms X sperm and store it The clitellum secretes a mucous cocoon - slides along worm picking up its eggs and then the stored sperm Cocoon slips off worm into soil and protects embryos during development

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105 Movement Muscles in each segment contract and elongate

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108 Leeches Class Hirundinea Carnivorous predators &/or parasites

109 Blade-like jaws - slit the host s skin or secrete enzyme that digests a hole in the skin Secretes numbing chem to prevent detection of the incision Secrete hirudin protein that prevents blood clotting

110 Medicinal Use Used to treat bruised tissues and for stimulating circulation of blood to fingers and toes reattached after being severed

111 Colored SEM of teeth of medicinal leech UP CLOSE AND PERSONAL

112 Following failed venous reconstruction with vein grafts, leeches were applied and color improved dramatically. Application continued every 4 to 6 hours. 5 days postoperatively, active range of motion was begun. 8 days postoperatively, venous flow was sufficiently restored. 3 weeks postoperatively, a skin graft was performed. 6 weeks postoperatively, following treatment with active and passive movement as well as coban taping, the finger has a TAM of 224 degrees. Leeches U.S.A. LTD

113 A 45-year-old, white male patient who suffered a complete avulsion of the upper twothirds of his right ear. The ear was reattached. 24 hrs after surgery 48 hrs 72 hrs 6 days 2 months after surgery Leeches U.S.A. LTD

114 Phylum Nematoda The Roundworms

115 The Nematodes Cylindrical, bilateral bodies with tapered ends Caenorhabditis elegans species used by scientists for experiments Small, tiny, transparent, only 959 body cells Easy to observe and manipulate

116 Many are agricultural pests Some are animal parasites: Ascaris lumbricoides largest intestinal worm to infect humans Cause stomach pain, vomiting, fever, wheezing, and abdominal tenderness and worm move through intestines

117 Trichinella spiralis Attach to intestines of pigs and game animals Eggs develop and migrate to blood and muscles Causes Trichinosis

118 Wuchereria bancrofti causes elephantiasis

119 Pinworms caused by Enterobius vermicularis live in the human rectum Common in young children

120 Phylum Mollusca

121 Phylum Mollusca Snails, slugs, oysters, clams, octopuses, squids Bilateral Symmetry Soft bodied, most protected by hard CaCO 3 shell Squids and octopuses have reduced, internalized shell or no shell

122 3 parts Molluscan Body Plan Foot for locomotion Visceral Mass containing most of the internal organs Mantle heavy fold of tissue that surrounds the visceral mass and secretes the shell Radula present in many molluscs fxns as a rasping tongue to scape food from surfaces

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125 Class Bivalvia Clams, oysters, mussels, scallops Shell divided in 2 halves May extend foot for mobility or anchorage Mantle contains gills for gas X and feeding Most are suspension feeders Traps small food particles in mucus coating of gills and use cilia to move particles to mouth Water enters incurrent siphon, moves over gills, exits an excurrent siphon No radula or distinct head

126 Sedentary lives Use foot as anchor in sand/mud Sessile mussels secrete threads that anchor them to rocks, docks or other hard surfaces

127 Scallops propel themselves along the sea floor by flapping their shells Light sensitive eyes of scallop

128 Class Gastropoda Snails and Slugs Herbivores - use radula to scrape food Torsion during embryonic development Causes anus to develop above head of adult Most have shell (exceptions are slugs and nudibranchs) Many have distinct heads with eyes at tips of tentacles

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132 Class Cephalopoda Squids and octopuses Carnivores Use beaklike jaws to crush prey Mouth is at center of several long tentacles Mantle covers visceral mass Shell reduced and internal in Squids Shell totally absent in Octopuses

133 Closed circulatory system blood is always contained in vessels Well developed nervous system complex brains capable of learning Well developed sense organs

134 Chambered Nautilus Only shelled cephalopod alive today

135 Squids Swim backward in open water

136 Octopuses Usually move along sea floor in search for food instead of swimming in open water

137 Phylum Echinodermata

138 1 ly bottom dwelling marine animals 5-pointed radial symmetry as adults Larvae are free-swimming, bilateral, filterfeeders Endoskeleton of calcium-rich ossicles

139 Class Asteroidea Sea stars 5 or more arms extending from a central disc Tube feet on undersurface of arms Regeneration abilities

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142 Class Holothuroidea Sea Cucumbers

143 Class Echinoidea Sea urchins and sand dollars

144 Class Ophiuroidea Brittle stars No suckers on tube feet

145 Class Crinoidea Sea Lilies Mouths point upward Used in suspension feeding

146 Class Concentricycloidea Sea daisies

147 Phylum Arthropoda The most successful phylum

148 Arthropods Segmented bodies Jointed appendages modified for walking, feeding, sensory reception, copulation and defense. Covered by cuticle exoskeleton constructed of layers of chitin and protein

149 Exoskeleton thin and flexible in joints, thick and hard elsewhere Provides protection and points of attachment for muscles Impermeable to water Must be shed for animal to grow (molt) and new one is secreted

150 Cephalization

151 Gas X Feathery gills in aquatic species Tracheal system in insects Book-lungs in other terrestrial forms (spiders)