Symbiosis & Corn

[unsung]

EK Lecture 9 Q208:

Although human behavior ensures the success of each new generation of corn, selective breeding by humans has genetically altered corn so that it could not survive in the wild without human intervention. Corn population is controlled, and most of the corn seeds are eaten or become spoiled. The relationship between humans and corn is best described as:

A. commensalism because humans benefit and corn is neither benefited nor harmed.

B. commensalism because there is no true benefit to either species.

C. parasitism because humans benefit and corn is harmed.

D. mutualism because both species benefit.

The book's answer is D, because humans eat corn, and (the genetically altered) corn can't survive without human intervention.

But I thought it would be C, because humans *altered* the corn so that it could not survive in the wild without us... so, aren't we harming the corn?

???

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[koopa_troopa]

I think you have to ignore what what happened in the past and just look at what is happening now. With humans, corn can grow. With corn, humans have food. The genetic modification was just a one time event. It doesn't really describe their relationship today.

 

[BloodySurgeon]

Well this is a similar relationship with humans and chickens. We fatten and genetically select large chickens so that it won't survive in the wild but will live longer as a species in our controlled environment. We are massively breeding them in chicken farms and they become evolutionary beneficial. Evolution only cares about the offspring, and even though the chickens have poor adaptations the fact is that humans cause the chickens to reproduce and have more offspring while the chickens help the humans by providing them with food to survive.

This is good to know, but really the way to think of it is to do what the above poster says: even though we caused the genetic modification, the fact is that they can't survive without us. We allow the following generations to continue and they aid in our survival as well. Therefore the answer is D.

 

[Scarletblack]

cool...I had the same question, but this makes sense...