1. Phylum Nematoda
a.k.a. the “roundworms”

3. Unlike Phylum Platyhelminthes, these worms are mostly free-living, not parasitic. They are found everywhere in the world in massive amounts! Ex. A small bucket of soil may contain more than a million nematodes!!! There could be up to a million species.

4. They are found in soil, salt flats, oceans, ocean trenches, deep mines, hot springs, aquatic sediments (dirt at bottom of a pond), and even Antarctica! Some inhabit beer coasters! Others are parasites! 80% of all individual animals on this planet are nematode worms!!!

5. The beer mat Nematode

6. Free-living flatworms can be carnivores, herbivores, and detrivores.
Ex. small animals, small algae, fungi, decaying organic matter, bacteria, and plant juices.
This last one results in tremendous crop damage around the world.

8. These critters have three tissue layers and a pseudocoelom.
Platyhelminthes also have three tissue layers but are acoelomate.
These organisms have a one-way digestive tract.
That means they have two openings, a mouth and an anus.

10. Nematodes lack a circulatory system.
They have a simple nervous system with several nerve cell bundles, (ganglia), that make up the brain.
Also, several longitudinal nerves.
They breath O2 and excrete metabolic waste such as ammonia, NH3, mostly by diffusion.
Muscles in body wall that allow them to move.

11. Round worms move like a person flapping around in a sleeping bag
Round worms move like a person flapping around in a sleeping bag! Roundworms reproduce sexually, and most of them are gonochoristic, (separate sexes). They lay many, many eggs.