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Herbicide: Yes or No?

Herbicide: Yes or No?. By Alyssa Volivar Period 3 PBL #4. Background Information/Research. Glyphosate - basically, Round-Up ESPS (5-enolpyruvylshikimate-3-phosphate synthase) - The gene that makes plants resistant to glyphosate Evolution - Genetic change in a population over time

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Herbicide: Yes or No?

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  1. Herbicide: Yes or No? By Alyssa Volivar Period 3 PBL #4

  2. Background Information/Research • Glyphosate • - basically, Round-Up • ESPS(5-enolpyruvylshikimate-3-phosphate synthase) • - The gene that makes plants resistant to glyphosate • Evolution • - Genetic change in a population over time • Mutation [random] • - influenced by environment • Migration (gene flow) • - population moves from location to location • - genes are merged through reproduction • Natural Selection [random] • - promotes organisms that are biologically fit and best suited for survival • Artificial Selection [non-random] • - humans get desirable traits in organisms through selective breeding

  3. Background Information/Research • Herbicide is being used to eradicate weeds • Crops are being genetically modified to be herbicide resistant • Weeds are becoming resistant to herbicide also • Ryegrass (Loliumrigidum) • - first resistant weed discovered in 1996 in Australia • 7-10 million acres of US land are affected by “superweeds” (2010) • 103 types of weeds within 63 species of weeds werereported to be resistant to herbicide (2006) • Fifteen weed species were confirmed resistant to glyphosate (2009)

  4. Superweeds in the U.S.

  5. Double-whammy! Problem 1: People believe that scientists making crops genetically resistant to glyphosate are unhealthy, and unnatural. Problem 2: Weeds are becoming more and more resistant to herbicides.

  6. (Yes, there’s a reason there’s two problems.)

  7. Factors • Weeds are mutating to become resistant • There are no alternative methods as effective as herbicides

  8. How Do We Stop This?! How about some good old GMO and selective breeding?

  9. How? There are resistant weeds, and there are non-resistant weeds. With the technology available today, humans have the ability to mess with genes and DNA to get the traits they want. Scientists can alter the ESPS strain of DNA (which makes the weeds resistant) and make them non-resistant plants again. Then, they can introduce them to their fields which are speckled with the resistant strains and over time, they will breed and mix traits. Eventually there will be more non-resistant strains of the weed. But in order for them to breed, farmers must not use herbicide in that area so as not to kill the weeds. By having more of the non-resistant weeds, our herbicides become effective once more. There will be less resistant weeds.

  10. How? In using such large amounts of herbicide, we are essentially committing genetic drift (non-randomly in this case). We are removing the population of weeds and their traits, millions at a time. By genetically modifying these weeds, we will be promoting artificial selection. We are choosing which traits we want and don’t want, in this case wanting to get rid of their resistance to glyphosate. We would also be promoting migration/gene flow by taking the non-resistant weeds and modifying them, then introducing them into a new environment riddled with resistant weeds, and then having them mix their traits. Here, genes are exchanged.

  11. Back to Problem #1 Many people don’t agree with humans interfering with genes and genetic structure of living organisms, but when it comes to plants, there have been no health risks yet. In fact, all modern plants are GMOs through the natural process of evolution. The point is, natural selection favors those that are biologically fit and have traits suited for survival. In the problem of weeds and crops, the WEEDS ARE WINNING. Other solutions to this problem are old fashioned tilling of the soil, hand-pulling weeds, and using multiple herbicides. But none of them are effective on such a large-scale or in the long-run.

  12. Back to Problem #1 Eventually, if this trend keeps up, our crops will be overrun with weeds and food production is going to go down. We need herbicides to keep weeds under control. And if scientists make crops non-resistant to the herbicides, whenever they use it the crops will die anyway. Herbicides SHOULD be allowed in private and commercial use as it is the best way to keep weeds under control. Also, there have been no health risks at all. Yes, culturally it may seem wrong to someone, but without herbicides, our food supply will go down anyway due to the resistant weeds.

  13. In a Nutshell • Herbicides are still the best method of getting rid of weeds. • We can modify them to become non-resistant and breed them. • There are no health risks involved with herbicides/GMO/GEOs. • Herbicides should be allowed in order to keep food supply going.

  14. For More Information… Farmers Learning Limits of Popular Herbicide https://www.youtube.com/watch?v=At371F4PrVI Older Herbicides Come Back Into Play Against Resistant Weeds https://www.youtube.com/watch?v=KwO8DD-HeTw

  15. Bibliography [CSE] Glyphosate [Internet]. 2013 [cited 2013 April 10]. Available from http://en.wikipedia.org/wiki/Glyphosate. Refuges of genetic variation: controlling crop pest evolution [Internet]. 1986 [cited 2013 April 10]. Available from: http://evolution.berkeley.edu/evolibrary/article/0_0_0/agriculture_04 Salas R., Dayan F, Pan Z, Watson S, Dickson J, - Scott R, Burgos N. ESPS gene amplification endows resistance to glyphosate in Italian ryegrass (Loliumperenesspmultiflorum) from Arkansas, USA. [Internet]. Pest Management Science. 2012. Available from: http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=276260

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