Phylum Nematoda
description
Transcript of Phylum Nematoda
Phylum Nematoda
RoundwormsMeans “Thread”
Aaugh! They are Everywhere! Every fist-full of dirt Every rotten apple Each square meter of lake
bottom Most are free living Most are parasites
Nematooooda! One study in Colorado estimated that
nematodes consumed about as much grass as a prairie dog colony.
Characteristics Tough outer covering- Cuticle No circular muscles- run lengthwise
(move with a crazy thrusting movement) Smooth, round, nonsegmented Tube within a tube Separate sexes 15,000 known species
Muscle Diagram
Examples
Hookworm- Sucks blood in
intestine Enters between the
toes by boring in the skin
Filaria Causes Elephantiasis Transfer by mosquito
Trichinella Causes trichinosis Found in pork
Pinworm Common among children Intense rectal itching Worms are visible near the anus at night
or early in the morning
Horsehair Worm Parasites on
grasshoppers, crickets, locusts, katydids, and beetles
Other hosts include dragonflies, spiders, millipedes, centipedes, and leeches
Persistent Many nematodes are able to suspend
their life processes completely when conditions become unfavorable; in these resistant states they can survive extreme drying, heat, or cold, and then return to life when favorable conditions return.