On pages 80-83 in the "Hey, Bud, Can You Do Me a Fava?" section (chapter 4) Dr. Sharon Moalem describes how plants use toxins for defense against predators. He also shows how different plant toxins affect humans in parts of the world. Moalem uses examples in history to show the effects some plant toxins can have in humans. This relates to Big Idea 1 (the process of evolution drives the diversity and unity of life) because evolution is the reason that plants have toxins so they can survive and reproduce.
First, find a plant that is consumed by humans and contains a toxin. What are the effects of the toxin? Then, explain why farmers cultivate the Indian vetch (page 80) even if it contains a powerful neurotoxin. Describe how jimsonweed took a part in Bacon's Rebellion (page 81). Why do people accidentally eat jimsonweed every year? Afterwards, explain why people get a burning sensation when they eat certain types of peppers and why water does nothing to help it. If the average human eats somewhere between 5,000 and 10,000 natural toxins every year (page 83), what do you think are the reasons behind this?
(Tyler Hagen-thagen4@students.d125.org)
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ReplyDeleteFirst off, some plants that are consumed by humans that contain toxins are apples that contain a toxin called amygdalin, and potatoes that contain solanine (http://www.nlm.nih.gov/medlineplus/ency/article/002875.htm).
ReplyDeleteIn page 80 of Survival of the Sickest, Moalem describes the reason that farmers cultivate the Indian vetch crop because the neurotoxins in the plant can help it survive while other plants are dying out. This is to do with evolution using the past Ap Biology evolution flowchart and the Big Idea 1. The plant has a variation, the neurotoxins, and it is favored for in Africa and Asia because it can last a lot longer during famines and droughts then other crops. Therefore the Indian vetch is selected for.
Another plant, jimsonweed, which has a variety of chemicals that can poison humans, was used to drug British soldiers who were sent to an early American colony, Jamestown during the Bacon's Rebellion. Although this made it hard for them to quell the rebellion, they eventually brought the rebellion to a stop. Many people happen to eat it today because it is mixed in with other plants from their garden (page 81). The reason many of these plants have these toxins is because in evolutionary history and still today, it helps the plants from getting eaten by animals. Solanaceae is a family of plants that include jimsonweed, eggplant, potato and tobacco, and these plants have a wide range of alkaloidal glucosides, a variety of chemicals.(http://www.sciencedaily.com/articles/s/solanaceae.htm)
Certain types of peppers, such as the habanero pepper, have toxins called capsaicin. "That burning sensation" after humans bite down on one of these very hot peppers is due to this toxin (page 82). This capsaicin sticks to mucous membranes in the body, allowing the heat of the pepper to stay so long, instead of being able to alleviate the heat by water. Again, these toxins are done by plants through the evolutionary process because they had a selection pressure of getting eaten by animals, and these traits allow them to be selected for and survive and reproduce easier.
We eat so many toxins through our food because so many plants we grow, that we do not see as harmful, such as apples, potatoes and eggplants, all have toxins that "researchers estimate that nearly 20 percent of cancer-related deaths are caused by" (page 83). A solution to this pressure of toxicity is to gradually, over time, evolve from humans that do not have mechanisms to manage these toxins easily, to humans that can easily manage these toxins in the body.
Rudy Viswanathan(aviswan4@students.d125.org)
Kidney bean or common bean produces a toxic substance known as phytohaemagglutinin, a lectin. This substance has various effects on the process of metabolism in cells. These include inducing mitosis and affecting cell membranes by altering their transport and permeability to proteins. It also agglutinates most red blood cell types of mammals. The symptoms of the presence of this substance in the body usually include nausea, vomiting, and diarrhea. But phytohaemagglutinin can be deactivated by cooking beans at 100 degrees celsius.
ReplyDelete(http://en.wikipedia.org/wiki/List_of_poisonous_plants)
On page 80 of “Survival Of The Sickest”, Dr. Moalem talked about how many farmers in Asia and Africa cultivate Indian vetch because of its ability to often survive when all other crops end up dying because of drought or infestation. The reason behind this is because of the presence of neurotoxins which helps to protect it against predators which are unable to consume the plant without being harmed. So these farmers grow Indian Vetch as an insurance crop so in an instance of drought or crop failure, the Indian Vetch will survive and will be available for consumption. But while these third world farmers consume Indian Vetch, there is a risk for becoming affected by the poison but it’s still a better option for them than starving.
On page 81, Dr. Moalem described the event of Bacon’s Rebellion during pre-colonial times where he attributed the use of jimsonweed by the British soldiers as hinderance in destroying the rebellion at first because it affected the soldier’s behavior by making them hallucinogenic. But people still manage to accidentally consume jimsonweed every year because it ends up getting mixed in with the other plants we consume from gardens. And the reason they continue to exists among these plants is because they can serve as adaptation for protecting plants from predators by killing animals and small insects which try to eat them when their toxins affect their bodies. This idea is related to Big Idea 1: The process of evolution drives the diversity and unity of life because with the presence of jimsonweed in some plants, there becomes an advantageous variation which may have helped previous and current species survive against predators which could have led to evolution.
When we consume pepper such as the habanero pepper, a burning sensation is produced by a chemical known as capsaicin just as Rudy stated. We are sensitive to it because it tickles the nerve fibers that sense pain and heat. Capsaicin also adheres to mucous membranes which explains why your eyes would hurt for so long if you accidentally rubbed them after handling peppers. It’s stickiness to mucous membranes also prevents it from being dissolved in water .
I believe that can the presence of toxins in our bodies can be partially beneficial to our bodies for stimulating natural detoxification. As the liver detects a rise in the presence of toxins in our body that we consume in plants, it will stimulates the detoxification of our blood to remove waste produced by our cells. By consuming 5,000 to 10,000 natural toxins each year we help to stimulate the liver to naturally clean out our blood more frequently when these substances are present.
(Prince Morkeh pmorkeh4@students.d125.org)