Nematoda and Rotifera Bilaterally symmetrical bodies with fluid filled space that holds storage areas and sperm and supports the body

Phylum Nematoda Made of roundworms Worms with long slender body that taper at both ends Psuedocoelomates-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 openings Food 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 nutrients Most 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 parasites Humans host 50 species

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

Female up to 30 cm, males much smaller Males hook in posterior to hold female during reproduction One female 200,000 eggs/day Eggs can live outside host for long time. Then enter another host where become larva Larva 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 feces Eggs produce larvae in damp dark soil Enter new host by boring into feet Then move to throat and lungs Swallowing takes them to the intestines where they mature Infect 400 million people world wide Most in tropical and subtropical region

Guinea worm video

Trichinella Infect humans, pigs, other mammals Live in walls of intestine of host Larvae travel to muscles, form cysts People get infected when eat undercooked meat The cyst release larvae which attach to intestine- become adults Infections=tricinosis Muscle pain, stiffness, death= results

Other parasitic round worms Pinworm-most common in human 16% of adults No serious disease 5-10mm in length-resemble white threads Live+mate lower intestines Eggs laid on skin around anus

Filarial worms Disease causing round worm in tropical countries Most dangerous live in lymphatic system Excess fluid system from cells up to 100 mm long, 4 inches Mosquitoes suck eggs out of blood Passed to another host when feeding Larvae then go to lymphatic system to start again. Ex. Elephantiasis, heartworm disease

Phylum Rotifera Rotifers=members of phylum Most transparent, free-living in fresh water Length of 100-500 micrometers males smaller gender Many can survive w/out water for long time Dry up till water can hydrate again look like sand psuedocolemates

Crown of cilia surounds mouth Sweeps food into dig, tract Food goes next into mastex, breaks food up Which is then digested in stomach Intestines absorb nutrients Waste pass through cloaca where all waste is collected Leave through anus Eggs leave same way from ovaries

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