Nematoda and Rotifera

Bilaterally symmetrical bodies with fluid filled space that holds storage areas

and sperm and supports the body

Phylum Nematoda

Made of roundwormsWorms with long slender body that taper

at both endsPsuedocoelomates-have psuedocoelom,

hollow-filled cavity lined by mesoderm on outside endoderm in inside

Range from 1 mm to 250 cm (4 ft)

Digestive track with 2 openingsFood enters the anterior mouth and waste

leaves through posterior anus created a digestive tract.

One direction Different parts of the tract able to do different

things i.e., absorb different nutrientsMost have different sexes and separated by a

non celled cuticle

80,000 species known, estimated 500,000 more

Majority free living on land, in salt water, in fresh water

Caenorhabditis elegans – C. elegans used to study development by biologists

150 species parasitesHumans host 50 species

ascaris

Genus of nematoda that are parasitesLive in intestines of pig, horses, humans.Feed on food as it passes through intestinesCan multiply and block intestines if not treated

Female up to 30 cm, males much smallerMales hook in posterior to hold female during

reproductionOne female 200,000 eggs/dayEggs can live outside host for long time. Then enter another host where become larvaLarva can travel through body including lungs

then mature worm goes back to intestines

http://images.google.com/imgres?imgurl=http://www.dpd.cdc.gov/dpdx/images/ParasiteImages/A-F/Ascariasis/Ascariasis_LifeCycle.gif&imgrefurl=http://www.dpd.cdc.gov/dpdx/hTML/ImageLibrary/A-F/Ascariasis/body_Ascariasis_il9.htm&usg=__eulZZrk2rYfgiDmjWhG7W2dxTG

Hookworms

Intestinal parasites

Mouth has cutting plates that secure onto host’ intestinal wall

Feed on blood if many present creates anemia in host

In children slow mental and physical development

Release eggs inside host’s fecesEggs produce larvae in damp dark soilEnter new host by boring into feetThen move to throat and lungsSwallowing takes them to the intestines

where they matureInfect 400 million people world wideMost in tropical and subtropical region

Guinea worm

video

Trichinella

Infect humans, pigs, other mammalsLive in walls of intestine of hostLarvae travel to muscles, form cystsPeople get infected when eat undercooked meatThe cyst release larvae which attach to intestine-

become adultsInfections=tricinosisMuscle pain, stiffness, death= results

Other parasitic round worms

Pinworm-most common in human 16% of adults

No serious disease5-10mm in length-

resemble white threadsLive+mate lower

intestinesEggs laid on skin around

anus

Filarial wormsDisease causing round worm in tropical

countriesMost dangerous live in lymphatic systemExcess fluid system from cells up to 100 mm long, 4 inchesMosquitoes suck eggs out of bloodPassed to another host when feedingLarvae then go to lymphatic system to start

again.Ex. Elephantiasis, heartworm disease

Phylum RotiferaRotifers=members of phylumMost transparent, free-living in fresh waterLength of 100-500 micrometers males smaller

genderMany can survive w/out water for long timeDry up till water can hydrate again look like

sandpsuedocolemates

Crown of cilia surounds mouth

Sweeps food into dig, tractFood goes next into mastex,

breaks food upWhich is then digested in

stomachIntestines absorb nutrientsWaste pass through cloaca

where all waste is collectedLeave through anusEggs leave same way from

ovaries

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Using your notes come up with 3 similarities btw rotifers and roundworms