NEMATODANEMATODA

CharacteristicsCharacteristics

RoundwormsRoundworms Name means “thread-Name means “thread-

like”like” Thought to be most Thought to be most

abundant animals on abundant animals on Earth (only about 20,000 Earth (only about 20,000 species identified, species identified, thought that there might thought that there might be more than 1,000,000)be more than 1,000,000)

Bilateral symmetryBilateral symmetry Size- all under 5mmSize- all under 5mm

AnatomyAnatomy

Long narrow bodies no Long narrow bodies no legslegs

PseudocoelomatesPseudocoelomates Mouth and Anus!Mouth and Anus! Excretion out of anusExcretion out of anus Outer covering called Outer covering called

cuticle is shed as worm cuticle is shed as worm grows usually 4 times grows usually 4 times during lifetimeduring lifetime

AnatomyAnatomy

No respiratory or No respiratory or circulatory systemscirculatory systems

No skeletonNo skeleton Two nerve cordsTwo nerve cords Has musclesHas muscles

FeedingFeeding

HerbivoresHerbivores BacterivoresBacterivores FungivoresFungivores PredatorsPredators OmnivoresOmnivores Parasites – picture is Parasites – picture is

of of TrichinellaTrichinella in pork in pork meatmeat

Trichinella spiralisTrichinella spiralis

Found in pork meat Found in pork meat that is undercookedthat is undercooked

Symptoms – nausea, Symptoms – nausea, diarrhea, muscle diarrhea, muscle pain as worms pain as worms invade, cardiac invade, cardiac problems, problems, pneumonia, nervous pneumonia, nervous disordersdisorders

No cureNo cure

PinwormsPinworms

Intestinal worms- live in Intestinal worms- live in rectum of humansrectum of humans

Female worms leave Female worms leave rectum at night to lay rectum at night to lay eggs on surrounding skineggs on surrounding skin

Eggs can survive in Eggs can survive in bedding and clothing for bedding and clothing for 2 weeks2 weeks

Spread by ingesting Spread by ingesting eggseggs

Medicines kill worms - Medicines kill worms - curablecurable

Ascaris lumbricoidesAscaris lumbricoides

Intestinal roundwormIntestinal roundworm Female worm can Female worm can

produce up to 200,000 produce up to 200,000 eggs a dayeggs a day

Eggs ingested from food Eggs ingested from food contaminated with fecal contaminated with fecal mattermatter

Larvae hatch, burrow Larvae hatch, burrow through intestine, can through intestine, can migrate anywhere in migrate anywhere in bodybody

Medicines kill worms - Medicines kill worms - curablecurable

ReproductionReproduction

Reproduce sexuallyReproduce sexually Both males and Both males and

femalesfemales Usually males Usually males

smaller in size than smaller in size than femalesfemales

HabitatHabitat

Mostly found in soilsMostly found in soils Can be found at bottom Can be found at bottom

of deepest oceans to of deepest oceans to tops of highest tops of highest mountainsmountains

Found in tropics to polar Found in tropics to polar regionsregions

Everywhere on EarthEverywhere on Earth Some free-living, some Some free-living, some

parasitesparasites What are some biotic What are some biotic

and abiotic factors?and abiotic factors?

AdaptationsAdaptations

Parasites are “wide-Parasites are “wide-range” can infect range” can infect many hostsmany hosts

Nematodes have a Nematodes have a metabolically- metabolically- suppressed stage if suppressed stage if survival is threatenedsurvival is threatened

During drought they During drought they go into dormancy go into dormancy (like hibernation)(like hibernation)