Superweeds

Question 1

What is resistance?

Answer 1

The ability of an organism to avoid or repel attacks by biotic agents or to withstand the effects of abiotic agents.

Question 2

Outline the 6 steps of the evolution of resistance.

Answer 2

1. Variation in population.
2. Selection pressure (herbicide or pesticide).
3. Some individuals survive due to resistance to the herbicide.
4. Survivors pass on resistance to offspring.
5. Farmers then need to increase the herbicide dose in order to kill weeds, repeating the process above will result in a population of weeds that are resistant to even higher doses of herbicide.
6. This cycle continues until the herbicide is ineffective against super weeds.

Question 3

Why or how is something considered a superweed?

Answer 3

• Transgenes may enter the genome from GMO crops providing a survival advantage. Advantages may include pest and herbicide resistance and lower water requirement.
• Factors limiting growth of the transgenic plant are removed making them more difficult to control.
• Monopolise or deplete other resources.
• Outcompete other plants