2Phylum Plathyhelminthes FLAT WORMS~13,000 species
3Flatworms, liver flukes, tapeworms Usually parasitic Can be free living and carnivoresCan be aquatic or terrestrial
4Body structureSoft, Flattened, AcoelomatesKeeps body cells in direct contact with O2Bilaterally symmetricalCephalizedHave true tissues and organsTwo way gut
5Gas exchange occurs by diffusion through skin Have tissues and internal organsHave all 3 germ layers.Gas exchange occurs by diffusion through skinPharynx - muscular tube that extends through the mouth and through which food is ingested
6Planarians have flame cells to regulate body fluid volume and composition Body fluids are filtered across the flame cells.Waste is excreted through pores to the outside.
7A branched gastrovascular cavity is site of extracellular digestion and distributes nutrients about the body Simple nervous system:a. Paired ganglia form a brain. b. Sensory cells are in the body wall.
8Sexual and asexual reproduction Asexual: Through regeneration -Able to regenerate any lost partsSexual:HermaphroditesBoth worms exchange spermFertilized eggs are enclosed in a cocoon and hatch in two to three weeks into tiny wormsPlanaria
10Classes 1-Turbellaria Planaria and relatives Free living, marine and freshwaterTwo light-sensitive eyespotsCLIP
11Flukes-blood, liver, lung Head ends has suckers or hooks 2- TremotodaFlukes-blood, liver, lungHead ends has suckers or hooksHave reduced digestive, nervous, and excretory systems.Reproductive systems are well developed and usually hermaphroditicParasitic- infecting the intestines of their hostCovered by teguments that protect them from host digestive juices.Examples:Schistosoma mansoni- blood flukeBurrow through skin, lay eggs in intestines and past out of bodyCause tissue decay
123-CestodaTapewormsAbsorbs nutrients through bodyTaenia echinococcus-Can grow to 30 ft long-Has hooklets (Scolex) for attachmentNo digestive systemAbsorb nutrients directly through skinProglottids-Segments of the worm
13Each proglottid segment contains a full set of both male and female sex organs
14Humans can be infected by eating beef that has not been cooked well The tapeworm attaches to the lining of the host with suckers and hooks
15A tapeworm scolex contains hooks and suckers for attachment to intestinal wall of host. Behind the head is a short neck and then a long string of proglottids.
16Life cycle of TapewormTapeworm releases packets of eggs which exits with the host feces. Some eggs end upon grass on in fieldCow eats grassEggs hatch and burrow into cow’s muscles, where they can become dormant
17The blood fluke Schistosoma infects 200 million people, leading to body pains, anemia, and dysentery.
19Roundworms (nematodes), hookworms Free-living and parasitic Aquatic and terrestrialShaped like thick threads and tapered on both ends
20Unsegmented, bilateral symmetry Pseudocoelom One way gut Movement:Contracting muscles-whip-like motion from longitudinal musclesBodyUnsegmented, bilateral symmetryPseudocoelomOne way gutExchange gases through body walls-through diffusion
22-Most species have separate sexes -Internal fertilization Reproduction:-Most species have separate sexes-Internal fertilization
23-In humans, can be contracted by eating infected pork. DiseasesTrichinosis--Humans, Pigs-In humans, can be contracted by eating infected pork.-Symptoms include abdominal pain, nausea, puffy and swollen face, headache and vomiting. Can have permanent damage to the heart muscles.-Recovery in about 6 months-5% of cases are fataltrichina worm: TrichinosisTrichinella spiralis
24Trichinosis After maturation, female adult burrows into wall of small intestine and produces living offspring that are carried by bloodstream to skeletal muscles where they encyst.Muscle Biopsy Showing Trichinosis
25Ascarid Worm:Matures in the intestines of the hostEating vegetables that are not washedHookworms:SoilWalking barefootanemia, malnutrition, and in children causes under-development
26Lives in blood and lymph vessels of birds and mammals Filarial WormTropical regionsLives in blood and lymph vessels of birds and mammalsUsually causes elephantiasisEndemic in central Africa, Turkey, India, Southeast Asia, Australia, Philippines, and South Americatransmitted by mosquitoesAfter infection, the adult filarial worms migrate to and live in the lymphatic ducts of humans. There, they clog up the blood vessels and cause the enlargement of the various body parts. The worms then infiltrate connective tissue.
27Guinea worms Contaminated water containing infected water fleas Once in the human intestine, larvae burrow into surrounding tissue.The worms mate.Males die soon after, but pregnant females continue to grow.As adults, each threadlike worm can be three feet long and harbor three million embryos. More than one guinea worm can infect a person at the same time.About eight months later, the female prepares to expel mature embryos by migrating toward the skin surface.Extreme pain occurs as the worm emerges from under the skin, often around the infected person's ankle.The pain is temporarily relieved by immersing the area in water, an act that contaminates the water and starts the cycle again.
29Diffusion of O2 and CO2 through moist skin Ranging in length from less than 1 mm to 3 m for the giant Australian earthworm.Annelids live in the sea, most freshwater habitats, and damp soil.Diffusion of O2 and CO2 through moist skinSegmentation allows a high degree of specialization of body regions.Groups of segments are modified for different functions.
30Segmented, Coelomates, Bilateral symmetry One way gutEx: Earthworms,leeches
31Movement: By alternating the two groups of muscles 1- Longitudinal shorter or fatter2- Circularlonger or thinner-Setae: bristlesanimation
32Feeding and Digestion: -Feed by sucking in soil and decaying matter -Earthworms move food through the pharynx-esophagus-crop-gizzard-intestinesA muscular pharynx draws food into the mouth.Food is stored in a crop and ground up in a muscular gizzard.Gizzard can contain sand to aid in breakdown.ChemMech
33Intestine Gizzard & Crop Pharynx Absorption- Large folds in the upper surface of the intestine –typhlosole (increases surface area)IntestineGizzard & CropPharynx
34Closed circulatory system Heart consist of five pairs of aortic archesBlood contains hemoglobin
38Excretory system involves nephridia. a. Coiled nephridia tubules in each segment have two openings: one is a ciliated funnel that collects coelomic fluid, and the other is an exit through body wall.b. Between the two openings, a coiled nephridia tubule removes waste from blood vessels.
39Reproduction:SexuallySome have separate sexes and some are hermaphrodites (earthworms and Leeches)
40Earthworm: Clitellum secretes slim that contain eggs and sperm- the ring then becomes a cocoon- young worms hatch a week later.
41The received sperm are stored while a special organ, the Clitellum, secretes a mucous cocoon.
42Nervous system has a brain connected to a ventral solid nerve cord; a ganglion is in each segment. Long ventral nerve cord leads from brain to ganglionic swellings and lateral nerves in each segmentnerve cord on the body cavity's ventral surface
43Classes of Annelida:1- Oilgochaeta-Stream-lined bodies, few setaeEarthworms, Tubifex Worms
44Moist-tropical Climates 2. HirudineaLeechesMoist-tropical Climatesmost are parasitesuse suckers to attach to host and blade-like teeth to make cut in host’s skin.once used by doctors for bloodlettinghermaphroditicaquatic and terrestrialWere used to treat medical conditions-Keep blood from coagulating by hirudin, an anticoagulant in their saliva
453. Polychaeta (marine worms ) Sandworms, Blood WormsLive in Cracks and Creases in coral reefs, sand, mud, piles of rocks.
46Parapodia are paddle-like appendages used in swimming and for respiration.
47Ecology:Recycling in natureDiet of many birdsDiet of fish
48The evolutionary significance of the coelom cannot be overemphasized. The coelom provides a hydrostatic skeleton that allows new and diverse modes of locomotion.It also provides body space for storage and for complex organ development.The coelom cushions internal structures and separates the action of the body wall muscles from those of the internal organs, such as the digestive muscles.