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
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
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