Presentation on theme: "WORMS clip FLAT WORMS ~13,000 species Flatworms, liver flukes, tapeworms Usually parasitic Can be free living and carnivores Can be aquatic or terrestrial."— Presentation transcript:
FLAT WORMS ~13,000 species
Flatworms, liver flukes, tapeworms Usually parasitic Can be free living and carnivores Can be aquatic or terrestrial
Soft, Flattened, Acoelomates Keeps body cells in direct contact with O 2 Bilaterally symmetrical Cephalized Have true tissues and organs Two way gut Body structure
Have tissues and internal organs Have all 3 germ layers. Gas exchange occurs by diffusion through skin Pharynx - muscular tube that extends through the mouth and through which food is ingested
Planarians 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.
A 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.
Reproduction Sexual and asexual reproductionAsexual: Through regeneration -Able to regenerate any lost partsSexual: Hermaphrodites Both worms exchange sperm Fertilized eggs are enclosed in a cocoon and hatch in two to three weeks into tiny worms Planaria
Classes 1-Turbellaria Planaria and relatives Free living, marine and freshwater Two light-sensitive eyespots CLIP
2- Tremotoda Flukes-blood, liver, lung Head ends has suckers or hooks Have reduced digestive, nervous, and excretory systems. Reproductive systems are well developed and usually hermaphroditic Parasitic- infecting the intestines of their host Covered by teguments that protect them from host digestive juices. –E–Examples: Schistosoma mansoni- blood fluke Burrow through skin, lay eggs in intestines and past out of body Cause tissue decay
3-Cestoda Tapeworms Absorbs nutrients through body Taenia echinococcus -Can grow to 30 ft long -Has hooklets (Scolex) for attachment No digestive system Absorb nutrients directly through skin Proglottids -Segments of the worm
Each proglottid segment contains a full set of both male and female sex organs
Humans 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
A 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.
Cow eats grass Cow eats grass Eggs hatch and burrow into cow’s muscles, where they can become dormant Life cycle of Tapeworm Tapeworm releases packets of eggs which exits with the host feces. Some eggs end upon grass on in field
The blood fluke Schistosoma infects 200 million people, leading to body pains, anemia, and dysentery.
ROUND WORMS ~500,000 species
Roundworms (nematodes), hookworms Free-living and parasitic Aquatic and terrestrial Shaped like thick threads and tapered on both ends
Body Unsegmented, bilateral symmetry Pseudocoelom One way gut Exchange gases through body walls- through diffusion M o v e m e n t : C o n t r a c t i n g m u s c l e s - w h i p - l i k e m o t i o n f r o m l o n g i t u d i n a l m u s c l e s
n o t f o r t h e s q u e a m i s h
Reproduction: -Most species have separate sexes -Internal fertilization
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 fatal Trichinella spiralis trichina worm: Trichinosis
Trichinosis 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
Ascarid Worm: Matures in the intestines of the host Eating vegetables that are not washed Hookworms: Soil Walking barefoot anemia, malnutrition, and in children causes under-development
Filarial Worm Tropical regions Lives in blood and lymph vessels of birds and mammals Usually causes elephantiasis Endemic in central Africa, Turkey, India, Southeast Asia, Australia, Philippines, and South America transmitted by mosquitoes After 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.
Guinea worms 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. Contaminated water containing infected water fleas Once in the human intestine, larvae burrow into surrounding tissue.
SEGMENTED WORMS ~12,000 species
Segmentation allows a high degree of specialization of body regions. –Groups of segments are modified for different functions. 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 O 2 and CO 2 through moist skin
Segmented, Coelomates, Bilateral symmetry One way gut Ex: Earthworms, leeches
Movement: -By alternating the two groups of muscles 1- Longitudinal shorter or fatter 2- Circular longer or thinner -Setae: bristles animation
Feeding and Digestion: -Feed by sucking in soil and decaying matter -Earthworms move food through the pharynx-esophagus-crop-gizzard-intestines A 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
IntestineGizzard & CropPharynx Absorption- Large folds in the upper surface of the intestine – typhlosole (increases surface area)
Closed circulatory system Heart consist of five pairs of aortic arches Blood contains hemoglobin
Nephridia (in each segment) for excretion of nitrogenous wastes, urea. Wastes are discharged through exterior pores
Metanephridia of an earthworm
Excretory 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.
Reproduction: Sexually Some have separate sexes and some are hermaphrodites (earthworms and Leeches)
Earthworm: Clitellum secretes slim that contain eggs and sperm- the ring then becomes a cocoon- young worms hatch a week later.
The received sperm are stored while a special organ, the Clitellum, secretes a mucous cocoon.
Nervous 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 segment nerve cord on the body cavity's ventral surface
Classes of Annelida: 1- Oilgochaeta- Stream-lined bodies, few setaeStream-lined bodies, few setae Earthworms, Tubifex WormsEarthworms, Tubifex Worms
2. Hirudinea Leeches Moist-tropical Climates most are parasites use suckers to attach to host and blade-like teeth to make cut in host’s skin. once used by doctors for bloodletting hermaphroditic aquatic and terrestrial Were used to treat medical conditions -Keep blood from coagulating by hirudin, an anticoagulant in their saliva
3. Polychaeta (marine worms ) Sandworms, Blood Worms Live in Cracks and Creases in coral reefs, sand, mud, piles of rocks.
Parapodia are paddle-like appendages used in swimming and for respiration.
Ecology: Recycling in nature Diet of many birds Diet of fish
The 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. Coelom
Name of Disease Causative Organism VectorDefinitive test Human Ascaroid Ascaris lumbricoides Drinking infected (sewage) water Stool sample HookwormNecator americanus Walk barefoot on soil w/ juvenile Fecal Sample TrichinosisTrichinella spiralis Eating pig meat w/encysted T. Spiralis Tissue Sample of Muscles look for encysted T. Spiralis ElephantiasisWucheria bancrofti Mosquito BiteBlood Sample look for microfilaria Guinea WormDracunculus medianansis drink water/ swallow cyclops blood test, look for microfilaria River Blindness Oncocerca volulus Black Flies" Eye WormLoa loaDeer fly" Dog Heartworm Dirofilaria immitus Mosquito, mostly Aedes culex "