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44 Cards in this Set
- Front
- Back
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flatworms are ____,____ worms that have tissues and internal organ systems. They are the simplest animals to have three embryonic _____ _____, ____ symmetry and ____
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soft, flattened
germ layers, bilateral, cephalization |
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flat worms are acoelomates or coelomates?
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acoelomates
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T/F flatworms lack cephalization and do not have a head region
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false
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flatworms are ____ and most of their ___ are close to the external environment. therefore, they rely on the process of _____, since materials can easily pass into and out of their bodies.
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thin, cells, diffusion
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which species is simpler in structure, parasitic or free-living? explain.
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parasitic; as they evolved into parasites, internal organs were modified or lost
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T/F all flatworms obtain food in the same way.
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False
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What muscular organ is used for feeding?
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pharynx
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What is the process to get food to the body tissues?
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food is digested by gust, nutrients are absorbed, digested food is diffused
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do all flatworms digest food in the same way?
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no
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why do many flatworms not need a circulatory system?
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because their bodies are so flat and thin
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flame cells function in what system?
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excretion
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what substances do flame cells remove?
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excess water, metabolic wastes
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the ganglia are part of what system?
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nervous
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What is the function of the specialized cells that flatworms have?
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detect external stimuli
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Two ways that flatworms move:
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1. cilia on their epidermal cells help then glide through water
2. muscle cells allow them to twist and turn so that they can react rapidly to environmental stimuli. |
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T/F Most free living flatworms are hermaphrodites.
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true
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What happens during sexual reproduction?
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Two worms join in pairs. They deliver sperm to eachother. Eggs are laid in clusters and hatch in a few weeks.
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How do flatworms reproduce sexually?
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fission
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3 main groups of flatworms:
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turbellarians, flukes, tapeworms
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common name for class turbellaria
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turbellarians
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are turbellarians free living or parasitic?
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freeliving
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environment of turbellarians
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marine or fresh water
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ex. of turbellarian
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planarians - " cross -eyed " freshwater worms
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common name for class trematoda
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flukes
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are flukes parasitic?
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yes
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environment of flukes
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internal organs of the host
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What 2 hosts are needed for the fluke life style?
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human and freshwater snails
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What type of environment does this cycle take place? (flukes)
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blood and water
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The Schistosoma blood fluke is responsible for what health problem, and in what part of the world is this disease a serious threat?
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schistosomiasis ; tropical areas
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Common name for class cestoda
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tapeworms
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are tapeworms free-living or parasitic?
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parasitic
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environment of tapeworms?
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intestines
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Why do tapeworms not have a digestive tract?
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pre-digested food can be absorbed through body cells
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What is the function of the scolex?
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contain suckers or hooks
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How do tapeworms obtain food?
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it uses its scolex to attach to intestinal wall and absorb nutrients
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What is found in a proglottid of a tapeworm?
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both male and female reproductive organs
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How do the zygotes get out of the host?
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in feces
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What is a cyst?
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a dormant protective stage
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How do humans become infected by the beef tapeworm?
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eating incompletely cooked meat containing cysts.
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To what class do tapeworms belong?
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Cestoda
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To what class do turbellarians belong?
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Turbellaria
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To what class do flukes belong?
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trematoda
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phylum of flatworm:
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platyheiminthes
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phylum of roundworm:
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nematoda
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