Nematoda(nematodes -Heterodera glycines)

By: Sarah Larsen5/19/09Period 4

Classification

• Usually classified into 5 main groups:

• Bacterivores- bacteria eating nematodes

• Fungivores- fungus eating nematodes

• Predators- eat other nematodes of the same size.

• Omnivores- eat more than one food material• Unknown- food source has not been

determined yet.

Body form, symmetry, and skeletal systems

• Tripoblastic: Has 3 germ layers… Ectoderm(cuticle), Mesoderm and Endoderm.

• Psuedocoelomate Animal: has a fully functional body cavity.

• Bilateral Symmetry: when one side of the body mirrors the other.

• Nematodes

do not have a

segmented

body.

Reproduction

• Generally sexual, sometimes asexual, involves internal fertilization.

• Most species, sexes are separate, the male is smaller than the female.

• Female nematodes can deploying over 100,000 eggs in a day.

Feeding and Digestive System

•Food is transported in the psuedocoloem by interior and exterior pressures.

•Three parts: stomodeum, intestine, proctodeum.

•The stomodeum = the “mouth and lips”, buccal cavity, and the pharynx (esophagus).

•Buccal cavity = tube that can contain small ‘teeth’ , food is sucked through the mouth into the buccal cavity.

Circulatory System

• Nematodes have a separate circulatory system made up of muscular tubes.

• Circulatory system: circulating fluid within the pseudocoelom.

Respiratory System

• Respiratory system: respiration by diffusion.

Environment

• Nematodes are mostly found naturally in soil.

• Parasitic nematodes will live in a host such as an insect or plant.

Human Interactions

• Some parasitic nematodes are the cause of many dangerous and even life-threatening diseases.

• Such as Trichinosis, Hookworm Infection, and Intestinal Roundworm Infection.

• Some are very helpful to people ‘cause they eat pests that can kill plants.

Unique Features

• 25,000 species have been identified, scientists estimate that that is only 5% of what could be out there.

• Over 50 species live in humans alone.

• Species range vastly in size, from under a millimeter to over a meter.

SpeciesHookworms(Ancylostoma duodenale)

Roundworms(Parascaris equorum)

Pinworms(Strongyloides stercoralis)

Bibliography

• www.cusmibio.unimi.it/.../nematodes/index3.htm

• http://www.eol.org/pages/2715• http://entnemdept.ufl.edu/creatures/nematode/soil_nematode.htm • Silverstein,Robert. Invertebrates. New York, N.Y.:Twenty-

First Century Books, 1996.• http://ucdnema.ucdavis.edu/imagemap/nemmap/ENT156HTML/vertlife

• http://nematode.unl.edu/digestive_system.html