Zoology Chapter 28
Terms
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- Flatworms
- Phylum Platyhelminthes
- Two Sided,right and left, only can be divided equally by one plane(cut in half). Flatworms are arranged this way.
- Bilateral Symmetry
- Concentration of newons tissues at the anterior end, BRAIN
- CEPHALIZATION
- Without a body cavity
- Acoelomate
- Dorsal
- Top
- Ventral
- Bottom
- Anterior
- Front
- Posterior
- REAR
- Three Classes
-
Turbellaria
Trematoda
Cestoda - Trematoda
- No digestive system, sucker used to attach to their host, no sense organs, no movement. Known as flukes. All parasitic. Asian liver fluke, sheep liver fluke
- Endoparasites
- Lives inside host
- Tegument
- Thick layer of cells to protect them from being digested
- Ectoparasites
- Lives on the outside of their hosts
- Turbellaria
- Free living, mostly marine,freshwater, most common is the Planeria. Lives under rocks in streams and ponds.
- Asexual
- In the summer they sttach their posterior ends and strech and tear in two. Have almost total regeneration
- Sexual
- Hermaphodites, cross fertilization
- Degeneration
- Lost certain characteristics of their ancestors, backwards evolution.
- Schistosoma
- blood flukes, passes through the skin from the water, kills 800,000 per year, infects 200 million in tropical regions.
- Clonorchis sinesis
- human liver fluke, get it by eating infected fish
- Cestoda
- Parasitic TAPEWORMS, Adult stage permentaly attach to intestinal wall of host, no digestive system
- digestion
- absorbs food from the host's intestine directly through their skin
- Proglottids
- Rest of teh tapeworm- rectangular body sections masses of reproductive organs, oldest at posterior ends
- scolex
- Head of tapeworm.knob shaped head with hooks and/or suckers
- Cysts
- larval tapeworms inside the meat, kill them by cooking
- Phylum Rynchocoela
-
Free living Marine worms
Length 1-100 ft
have a circulatory system and a digest tube that is open on both ends - Phylum Nematoda
-
Unsegmented roundworms
Pseudocelom
Free Living
Parasites - PSEUDOCOELOM
- False Cavity, cavity between middle layer and inner layer
- FREE LIVING
- Most Roundworms
- PARASITES
- About 50 species parasitize plants and animals
- ASCARIS
- Infects human intestines, eggs carried to soil in human waste, eggs can live for years
- NEMATODA EGGS Devlop Where?
- In the intestines and bore through the walls into blood vessels where they enter the blood and travel to the lungs
- How do the worms return to th eintestine to mate?
- Animal coughs them up and then swallows them, they mate, and their eggs pass out in waste.
- Necator
- Hookworms, bores through bare feet
- Trichinella
- Parasitic roundworms in pigs that causes trichinosis in humans. Cooking/freezing kills it.
- PHYLUM ROTIFERA
-
Have a row a cilia around the mouth
feed on bacteria and protists
and are well developed one way gut. - Flatworms have these systems
- Distinct centralized nrevous system, simple excretory system, and a complex reproductive system, a prmitive intestine (one opening for food and waste)
- What can Flatworms do to humans?
- Flatworms can cause misery and early death.
- Pork Tape Worm attaches to it host by what?
- 4 suckers and a row of hooks
- Beef Tapeworms attach to its host by what?
- 4 suckers
- Fish Tapeworm attaches to it's hosts by what?
- two groovelike attachment organs. NO hooks or suckers.
- Dog Tapeworm attaches to it's hosts by what?
- 4 suckers, lots of hooks.