Phylum Nematoda (Roundworms)
Roundworms are slender, unsegmented worms with tapering ends. They range in size from microscopic to a meter in length. Many are parasitic and live in hosts of almost every kind of plant and animal.
Body Plan:
Respiration, Circulation, and Excretion:
Roundworms have no internal transport system so they rely on diffusion to move waste and nutrients through their body. Reproduction:
Reproduce sexually. Male deposits sperm inside the female's reproductive tract, internal fertilization takes place. Parasitic roundworms often have life cycles that involve two or three different hosts or several organs within one host. |
Feeding:
Free living roundworms use grasping mouths and spines to catch and eat other small animals. Soil-dwelling and aquatic forms eat algae, fungi or pieces of decaying organic matter. Response:
Have simple nervous systems that have several ganglia. Nerves extend from ganglia in the head and run down the length of the body to control movement. Several types of sense organs detect chemicals given off by prey or hosts. Movement of round worms: http://www.youtube.com/watch?v=SpgjnXEFadg |
Classes of Roundworms
Filarial Worms:
Found in tropical regions of Asia, threadlike worms that live in the blood and lymph vessel of mammals.
Ascdarid Worms:
Can be found in humans and other vertebrate animals. Causes malnutrition by absorbing digested food. Spread by eating good not properly washed.
Hook Worms:
Eggs hatch outside the body and develop in soil. If they find an unprotected foot, they use sharp tooth-like hooks to borrow into skin and enter the blood stream. Travel through blood to hosts lungs and intestines, suck the host's blood, causing weakness and poor growth.
Filarial Worms:
Found in tropical regions of Asia, threadlike worms that live in the blood and lymph vessel of mammals.
Ascdarid Worms:
Can be found in humans and other vertebrate animals. Causes malnutrition by absorbing digested food. Spread by eating good not properly washed.
Hook Worms:
Eggs hatch outside the body and develop in soil. If they find an unprotected foot, they use sharp tooth-like hooks to borrow into skin and enter the blood stream. Travel through blood to hosts lungs and intestines, suck the host's blood, causing weakness and poor growth.