Presentation on theme: "Chapter 25 Worms and Mollusks"— Presentation transcript:
1Chapter 25 Worms and Mollusks Section 1: FlatwormsSection 2: Roundworms and RotifersSection 3: MollusksSection 4: Segmented Worms
2Body Structure of Flatworms Chapter 25Worms and Mollusks25.1 Flatworms (Phylum Plathelminthes)Body Structure of FlatwormsFlatworms are on the acoelomate branch of the evolutionary tree.Bilateral symmetryThin, flat bodiesDefinite head region and body organsLack a coelom2-way gut
325.1 Flatworms Feeding and Digestion Chapter 25Worms and Mollusks25.1 FlatwormsFeeding and DigestionFree-living flatworms feed on dead or slow-moving organisms.Parasitic flatworms have modified feeding structures called hooks and suckers, whichenable them to stay attached to their hosts.
4Respiration, Circulation, and Excretion Chapter 25Worms and Mollusks25.1 FlatwormsRespiration, Circulation, and ExcretionDiffusion moves dissolved oxygen and nutrients to all parts of their bodies.Carbon dioxide and other wastes also are removed from flatworm cells by diffusion.
5Chapter 25Worms and Mollusks25.1 FlatwormsFlame cells move water out of the body to excrete waste products and maintain water balance.
6The nervous system regulates the body’s response to stimuli. Chapter 25Worms and Mollusks25.1 FlatwormsResponse to StimuliThe nervous system regulates the body’s response to stimuli.
7Response to Stimuli 25.1 Flatworms 2 eyespots Chapter 25Worms and Mollusks25.1 FlatwormsResponse to Stimuli2 eyespots2 nerve cords that run the length of the bodyBrain-like structure called a ganglion which sends messages to/from the eyespots and along the nerve cords
8Move by contracting muscles in the body wall Chapter 25Worms and Mollusks25.1 FlatwormsMovementMove by contracting muscles in the body wallGlide by using cilia located on their undersides
9Flatworms are hermaphrodites. Chapter 25Worms and Mollusks25.1 FlatwormsReproductionFlatworms are hermaphrodites.Two different flatworms exchange sperm, and the eggs are fertilized internally.
10Free-living flatworms can reproduce asexually by regeneration. Chapter 25Worms and Mollusks25.1 FlatwormsFree-living flatworms can reproduce asexually by regeneration.
11Live in marine or freshwater Chapter 25Worms and Mollusks25.1 FlatwormsTurbellariansLive in marine or freshwaterHave eyespots that can detect the presence or absence of lightSensory cells help them identify chemicals and water movement.
12Parasites that infect the blood or body organs of their hosts Chapter 25Worms and Mollusks25.1 FlatwormsTrematodesParasites that infect the blood or body organs of their hostsThe parasitic fluke Schistosoma requires two hosts to complete its life cycle.These fluke eggs clog blood vessels, causing swelling and eventual tissue damage.
14Parasites adapted to life in the intestines of their hosts Chapter 25Worms and Mollusks25.1 FlatwormsCestodesParasites adapted to life in the intestines of their hostsProglottids form continuously; as new ones form near the scolex, older proglottids move farther back and mature.
1625.2 Roundworms and Rotifers (Phylum Nematods) Chapter 25Worms and Mollusks25.2 Roundworms and Rotifers(Phylum Nematods)Body Structure of RoundwormsFound everywhere from marine and freshwater habitats to landRoundworms have adaptations that enable them to live in many places.Bilateral Symmetry1-way gut
17Most roundworms are free-living. Chapter 25Worms and Mollusks25.2 Roundworms and RotifersFeeding and DigestionMost roundworms are free-living.The movement of food through the digestive tract is one-way.
18Respiration, Circulation, Excretion, and Response to Stimuli Chapter 25Worms and Mollusks25.2 Roundworms and RotifersRespiration, Circulation, Excretion, and Response to StimuliMost roundworms exchange gases and excrete metabolic wastes through their moist outer body coverings.Ganglia and associated nerve cords coordinate nematode responses.
19These muscles pull against the outside body wall and the pseudocoelom. Chapter 25Worms and Mollusks25.2 Roundworms and RotifersMovementMuscles cause their bodies to move in a thrashing manner as one muscle contracts and another relaxes.These muscles pull against the outside body wall and the pseudocoelom.
20Roundworms reproduce sexually. Chapter 25Worms and Mollusks25.2 Roundworms and RotifersReproductionRoundworms reproduce sexually.Fertilization is internal.Larva hatch from the fertilized eggs.
21Diversity of Roundworms Chapter 25Worms and Mollusks25.2 Roundworms and RotifersDiversity of RoundwormsTrichinella wormsHookwormsAscarid wormsPinwormsFilarial worms
22Chapter 25Worms and Mollusks25.2 Roundworms and RotifersNematodes in PlantsNematodes can infect and kill pine trees, soybean crops, and food plants such as tomatoes.
23Nematodes eat flea larvae, controlling the flea population in yards. Chapter 25Worms and Mollusks25.2 Roundworms and RotifersCertain nematodes are used to control the spread of cabbage worm caterpillars, Japanese beetle grubs, and many other pests of crop plants.Nematodes eat flea larvae, controlling the flea population in yards.
25Sensory structures include sensory bristles and eyespots on the head. Chapter 25Worms and Mollusks25.2 Roundworms and RotifersRotifersBilateral symmetryPseudocoelomatesExchange gases and excrete metabolic wastes by diffusion through body walls.Sensory structures include sensory bristles and eyespots on the head.
26Body Structure of Mollusks Chapter 25Worms and Mollusks25.3 Mollusks (Phlyum Mollusca)Body Structure of MollusksMollusks are coelomate animals with bilateral symmetry, a soft internal body, a digestive tract with two openings, a muscular foot, and a mantle.
28A radula scrapes food into their mouths. Chapter 25Worms and Mollusks25.3 MollusksFeeding and DigestionA radula scrapes food into their mouths.
29Chapter 25Worms and Mollusks25.3 MollusksMollusks have complete guts with digestive glands, stomachs, and intestines.
30Gills are parts of the mantle. Chapter 25Worms and Mollusks25.3 MollusksRespirationGills are parts of the mantle.Gills contain a rich supply of blood for the transport of oxygen to the blood and for the removal of carbon dioxide from the blood.
31is pumped out of vessels into open spaces surrounding the body organs. Chapter 25Worms and Mollusks25.3 MollusksCirculationis pumped out of vessels into open spacessurrounding the body organs.In an open circulatory system, bloodExposes organs to nutrient rich blood directly and removes wasterOxygen and nutrients diffuse into tissues that are bathed in blood and carbon dioxide diffuses from tissues into the blood.
32In a closed circulatory system, blood is confined to Chapter 25Worms and Mollusks25.3 MollusksIn a closed circulatory system, blood is confined tovessels as it moves through the body.System of entirely closed vessels (arteries and veins) – like oursA closed system efficiently transports oxygen and nutrients to cells where they are converted to usable forms of energy.Allows for quicker movement
33Nervous systems coordinate their movements and behavior. Chapter 25Worms and Mollusks25.3 MollusksExcretionMollusks get rid of metabolic wastes from cellular processes through structures called nephridia.Response to StimuliNervous systems coordinate their movements and behavior.
34Mollusks reproduce sexually. Chapter 25Worms and Mollusks25.3 MollusksReproductionMollusks reproduce sexually.All mollusks share similar developmental patterns.
35The largest class of mollusks is Gastropoda. Chapter 25Worms and Mollusks25.3 MollusksDiversity of MollusksGastropodsThe largest class of mollusks is Gastropoda.Most species of gastropods have a single shell.Abalones, snails, conches, periwinkles, limpets, cowries, whelks, and conesSlugs and nudibranchs do not have shells.
36Bivalves are two-shelled mollusks. Chapter 25Worms and Mollusks25.3 MollusksBivalvesBivalves are two-shelled mollusks.Clams, mussels, oysters, and scallopsUse a muscular foot to burrow into wet sandMussels attach to rocks with byssal threads.
37Cephalopods are the head-footed mollusks. Chapter 25Worms and Mollusks25.3 MollusksCephalopodsCephalopods are the head-footed mollusks.Squid, octopus, chambered nautilus, and the cuttlefishThe foot of a cephalopod is divided into arms and tentacles with suckers.Cuttlefish
38Cephalopod Protection Chapter 25Worms and Mollusks25.3 MollusksCephalopod ProtectionExpel water to propel themselves away from threatHideShoot out an inky substance that forms a cloudChange color to blend in with their surroundings
39Review of Characteristics Chapter 25Worms and Mollusks25.3 MollusksReview of CharacteristicsBilateral symmetry2 body openingsCoelomA muscular foot (or feet)A mantle (thin membrane that surrounds the internal organs)Some have shellsHeterotrophs – may be grazers, predators or filter feeders
40Body Structure of Segmented Worms Chapter 25Worms and Mollusks25.4 Segmented Worms (aka Earthworms)(Phlyum Annelidia)Body Structure of Segmented WormsAnnelids undergo protostome development.Include earthworms, marine worms, and parasitic leechesSegmented and have a coelom
41Segments can be specialized. Chapter 25Worms and Mollusks25.4 Segmented WormsRigidity in annelid segments creates a hydrostatic skeleton that muscles can push against.Segmentation also permits segments to move independently of each other and enables a worm to survive damage.Segments can be specialized.
42Chapter 25Worms and Mollusks25.4 Segmented WormsFeeding and DigestionRunning through all earthworm segments from the mouth to the anus is the digestive tract.
43Most annelids have a closed circulatory system. Chapter 25Worms and Mollusks25.4 Segmented WormsCirculationMost annelids have a closed circulatory system.
44Respiration and Excretion Chapter 25Worms and Mollusks25.4 Segmented WormsRespiration and ExcretionEarthworms take in oxygen and give off carbon dioxide through their moist skin.Aquatic annelids have gills for the exchange of gases in the water.Segmented worms have two nephridia in almost every segment.
45The anterior segments are modified for sensing the environment. Chapter 25Worms and Mollusks25.4 Segmented WormsResponse to StimuliThe anterior segments are modified for sensing the environment.
46The earthworm contracts circular muscles running around each segment. Chapter 25Worms and Mollusks25.4 Segmented WormsMovementThe earthworm contracts circular muscles running around each segment.This squeezes the segment and causes the fluid in the coelom to press outward like paste.
47The fluid pressure causes the segment to get longer and thinner. Chapter 25Worms and Mollusks25.4 Segmented WormsThe fluid pressure causes the segment to get longer and thinner.The earthworm contracts the longitudinal muscles that run the length of its body.This causes the segment to shorten and return to its original shape, pulling its posterior end forward and resulting in movement.
48Reproduce both sexually and asexually Chapter 25Worms and Mollusks25.4 Segmented WormsReproductionReproduce both sexually and asexuallySperm are passed between two worms near segments called the clitellum.
49Earthworms and their relatives Chapter 25Worms and Mollusks25.4 Segmented WormsDiversity of AnnelidsEarthworms and their relativesMarine annelidsLeeches
50Characteristic Review Chapter 25Worms and Mollusks25.4 Segmented WormsCharacteristic ReviewBilateral symmetry2 body openingsCoelom‘tube within a tube’Live on land, in soil, freshwater and/or saltwaterMost have setae (help the animal move)
51Chapter Resource Menu Chapter Diagnostic Questions Worms and MollusksChapter Resource MenuChapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practicebiologygmh.comGlencoe Biology TransparenciesImage BankVocabularyAnimationClick on a hyperlink to view the corresponding feature.
52Identify the method of asexual reproduction used by flatworms. Chapter 25Worms and MollusksChapter Diagnostic QuestionsIdentify the method of asexual reproductionused by flatworms.regeneration of body partsproduction of both eggs and spermrelease of cocoons into the waterproduction of sporesABCDCDQ 1
53Which organs does a flatworm lack? Chapter 25Worms and Mollusks25.1 Formative QuestionsWhich organs does a flatworm lack?musclesrespiratory organsdigestive organsexcretory organsABCDFQ 2
54Which flatworm is not a parasite? Chapter 25Worms and Mollusks25.1 Formative QuestionsWhich flatworm is not a parasite?flukeplanariantapewormtrematodeABCDFQ 3
55What body plan do roundworms and rotifers have? Chapter 25Worms and Mollusks25.2 Formative QuestionsWhat body plan do roundworms androtifers have?acoelomatecoelomateprotocoelomatepseudocoelomateABCDFQ 4
56What organ does a mollusk use to feed? Chapter 25Worms and Mollusks25.3 Formative QuestionsWhat organ does a mollusk use to feed?footmantleradulatentacleABCDFQ 8
57A B What type of circulatory system do highly active animals require? Chapter 25Worms and Mollusks25.3 Formative QuestionsWhat type of circulatory system do highlyactive animals require?open circulatory systemclosed circulatory systemABFQ 9
58In what group of animals are the earthworms, polychaetes, and leeches? Chapter 25Worms and Mollusks25.4 Formative QuestionsIn what group of animals are the earthworms,polychaetes, and leeches?annelidsnematodestrematodesrotifersABCDFQ 13
59Which annelids are parasites? Chapter 25Worms and Mollusks25.4 Formative QuestionsWhich annelids are parasites?earthwormsleecheslumbriculid wormstubifex wormsABCDFQ 15
60How are leeches different from parasitic flatworms and roundworms? Chapter 25Worms and Mollusks25.4 Formative QuestionsHow are leeches different from parasiticflatworms and roundworms?Leeches have a mouth.Leeches feed on humans.Leeches do not have setae.Leeches are external parasites.ABCDFQ 16
61Chapter 25Worms and MollusksChapter Assessment QuestionsIdentify the body structure that free-living flatworms use for feeding.hookssuckerpharynxciliaABCDCAQ 1
62A B Flatworms have radial symmetry. True False Chapter 25Worms and MollusksChapter Assessment QuestionsFlatworms have radial symmetry.TrueFalseABCAQ 3
63Which organism is a coelomate? Chapter 25Worms and MollusksStandardized Test PracticeWhich organism is a coelomate?flatwormmolluskrotiferroundwormABCDSTP 1
64Which step in the life cycle of this parasite will be Chapter 25Worms and MollusksStandardized Test PracticeWhich step in the life cycle of this parasite will bebroken if proper sewage treatment is implemented?BCDEAABCDESTP 2
65Which organism is a cephalopod? Chapter 25Worms and MollusksStandardized Test PracticeWhich organism is a cephalopod?ABCDSTP 5
66circulatory digestive excretory nervous Chapter 25Worms and MollusksStandardized Test PracticeWhich body system in mollusks is absent inflatworms, roundworms, and rotifers?circulatorydigestiveexcretorynervousABCDSTP 6