Invertebrate Animal Phyla: Worms - duxbury.k12.ma.us · Invertebrate Animal Phyla: Worms Domain:...
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Transcript of Invertebrate Animal Phyla: Worms - duxbury.k12.ma.us · Invertebrate Animal Phyla: Worms Domain:...
Invertebrate Animal Phyla: Worms
Domain: Eukaryota
Kingdom: Animalia
Worms in general:
*Symmetry =
What are the two benefits of this kind of symmetry?
There are three Phyla of "worms"
PHYLUM PLATYHELMINTHES “flatworms”
Ex. Planaria, Flukes, Tapeworms* 20,000 species
* Can be parasitic (flukes, tapeworms) or free-living (planaria).
* 1st animals in which tissues are organized into organs and organ systems.
*No body cavity.
* Flattened body dorsal and ventral.
* Have a Central Nervous System (CNS).Define:
* Well developed muscular system.
* One opening to the gut (still). Mouth/Anus
* Parasitic worms can have life cycles with multiple hosts.
Planaria Tapeworm
Tapeworm head (scolex) Fluke
Flatworm cross Section
Fluke Life Cycles
PHYLUM NEMATODA “roundworms”
Ex. Ascaris, hookworm, heartworm
* 10,000-15,000 known species. 1/2 million estimates. Very underestimated because many are hardly seen because they are small or internal parasites.
* Most are parasitic of plants and animals. Also found in great numbers in marine sediments rich in organic matter.
*Body Cavity
* Mostly small with cylindrical bodies usually pointed at each end.
* One way digestive tract; separate mouth and anus!
* Have a hydrostatic skeletonDefine:
* Very common parasites in most marine animals—sushi
Nematodes
Ascaris
Roundworm cross section
Nematode Life Cycles
Why you don't have to worry about parasitic worms.
* Sewage treatment
* Water treatment
* Cooking meat kills cysts and eggs
* USDA inspects
* Farming regulations for raising pigs
PHYLUM ANNELIDA “segmented worms”
Ex. Leeches, Earthworm, Seaworm (Nereis)
* 12,000 species
* Body consists of similar, repeating segments.
*Body Cavity
* Hydrostatic skeleton.
* Flexibility provided by segmentation allows for efficient crawling and burrowing.
* Closed circulatory system.Define:
* Most marine worms are found in the Class Polychaeta.~Each body segment has a pair of parapodia
Function?
Segmented Worm Cross Section
* Marine worms have a ciliated, planktonic larval stage called a trochophore larva.
Trochophore larva have been studied because the mollusks also have this larval stage in their life cycle.
* Some adults are predators of small prey. Others are deposit feedersDefine:
Trochophore Larvae
Leech Earthworm
SeawormSeaworm parapodia