Parasitic and Non-Parasitic Organisms. Specifically,

¶ … parasitic and non-parasitic organisms. Specifically, it will discuss the parasitic hookworm, and the non-parasitic worm planaria, including research into the organisms.

Planaria

Planaria are non-parasitic flatworms that live in both fresh and saltwater areas. Some can also live on land, under rocks or logs or in other moist areas. They can be 1/8 of an inch to almost an inch long, and they are often used in laboratory experiments and study. They are not harmful to humans. They feed on detritus, along with other living and dead matter, and they are carnivorous. They move by using cilia to glide along the ground. Since they are non-parasitic, they do not have a host or a method of transmission.

They are currently used in a variety of different research, largely because they can regenerate. If they are cut in two, either lengthwise or crosswise, they can regenerate into two new creatures. They are beneficial because they can be used in a variety of scientific applications, and they aid learning in the classroom. Perhaps the most famous research using planaria includes research by scientist James V. McConnell, who studied them during the 1950s and 60s. He based his "Memory RNA" theories on his findings with the worms. His research involved showing the worms a bright light and then giving them an electric shock. After several experiments, when the worms viewed the light, they reacted as if they had been shocked, even when they were no longer shocked. He then cut them up, and the regenerated animals regained the learning and reacted to the light as if they had been shocked, as well. He determined that memory can be transmitted through chemicals, and this helped develop his memory RNA theory, however, his results have not been able to be replicated by modern scientists.

Planaria are flat worms, nematodes are round worms, such as the hookworm discussed below, and round worms, or nematodes do not beneficially affect them.

Hookworm

The hookworm is a parasitic worm that enters the body through sweat glands or hair follicles in the skin. This sets them apart from most other worms, which usually enter through the stomach. They usually live in human feces, and that is how they are transmitted to humans, they walk through, sit, or lie in contaminated dirt, and the worms transfer to their human hosts. They travel through the blood vessels to the lungs, where they can cause shortness of breath and coughing, and then they move on to the throat, where the host swallows them and they flow to the small intestine. They can grow to about .4 inches long, and they suck blood out of the walls of the intestine, which can cause anemia and abdominal pain. They mostly affect people living in African, China, Southeast Asia, and Latin America, and the World Health Organization believes that as many as 740 million people suffer from hookworm (Ballantyne, 2010). They are treated with medications that are extremely effective and have few side effects.