On page 102-103, Moalem talks about the actions of a tiny worm called dicrocoelium dentriticum that lives inside sheep and cattle. Moalem shows the worm's cycle of life from egg to offspring and how they return to a different host if their first host dies. The worm's offsprings will travel through the feces, snails, and ants. Finally to return by making the ant commit suicide. This relates to Big Idea 4: Biological systems interact, and these systems and their interactions possess complex properties.
With the dicrocoelium dentriticum in mind determine why living inside of a sheep or cattle provides the worm with selective advantages. Keep in mind the rules of survival we learned such as living space. Next determine how the worm has the ability to take over the ant's nervous system causing the ant to act uncharacteristically. Does the worm require certain proteins in order to control the ant or is there another mechanism?Also research what selective advantages could a parasite gain from infecting a specific host; for example, what selective advantages are there for dicrocoelium dentriticum to infect the cattle or sheep as opposed to a human. Use these results to come up with a solution to reduce the number of parasitic infections or why these infections benefit the ecosystem in the long run.
Jimmy Wang jimmypelewang@gmail.com
Dicrocoelium dentriticum is just one of many examples of parasites in different ecosystems. The symbiosis relationship between the warm and its host is a parasitic relationship where one species benefit and the other species is harmed. The relationship is related to the big idea 4 because dicrocoelium dentriticum depends on the host to provide for shelter and food. Although the host is getting harmed, the warm is involved in this coordinated system, allowing the warm to be “alive, growing, and reproducing”. According to page 103, Moalem discusses how because the warm needs to live in a sheep, the warm makes its host ant to be “suicidal” and to be eaten by a sheep. Even though the ant will die, the warm gets to survive and grow in a sheep.
ReplyDeleteDicrocoelum dentriticum are seen in humans although it is very rare. Dicrocoelum dentriticum are seen inside a liver of sheeps or cattles because of their diet since cattles and sheeps eat grass and many ants which are another host to the warm also are near grass. These warms control ant’s brain in a interesting manner and do not need any specific protein. The warms travel to the ants’ abdominal cavity, where the warms grow. The warms then travel to the brain causing a cataleptic cramp that paralyzes the ant when the ant is on a tip of grass when the temperatures get below 15 c. By freezing the ants on grass, sheeps easily eat ants by mistake and the warm gets to live in a sheep.
The liver of grazing animals provide ideal shelters for dicrocoelum dentriticums. The liver of grazing animals have blood supply that has all the nutrients that the parasite need to survive. The parasite don’t necessary prefer living in a grazing animal from humans but the parasites are usually in a cycle involved with growing up in ants that humans don’t eat. Since these parasites live and grow in ants where plants are, when doing a garden work or farming, it is best to wear gloves to avoid parasites to creep in on you.
http://www.askmedrug.com/5708
http://www.dpd.cdc.gov/dpdx/HTML/Dicrocoeliasis.htm
http://www.nr.gov.nl.ca/nr/agrifoods/animal/animal_health/vs_02_001_lancet_fluke_of_sheep.pdf
(Woosik Choi per. 6b,7 – wchoi3@students.d125.org)