Saturday, April 09, 2005

Life's Top Ten Greatest Inventions

NewScientist has a good article on its selections for Life's Top Ten Greatest Inventions. My favorites are the last three on the list: parasitism, superorganisms and symbiosis.



Blogger Unknown said...

Do you think parasitism and symbiosis are related? But I agree with your choices.

5:41 AM  
Blogger Henry said...

I was about to embark on a prolonged explanation of what I think is the relationship between symbiosis and parasitism, when I grabbed an old Biology book and all these words came out at me which I had not given any consideration in a long time. So instead, I will list them(in no particular order) and let their presence speak for the continuum which exists.
Symbiosis, mutualism, commensalism, parasitism, predation, antibiosis.
Also, I found a new spin (or at least new to me) on the lichen. I would have named the lichen as a classic example of a mutualistic relationship. It was mentioned however that some considered it to be an example of "controlled parasitism" were the algal element is eventually consumed by fungal growth. I haven't investigated to determine the current dominant view, but it is an interesting thought and is also appropriate for this conversation. Would you consider our agriculture to be an example of controlled parasitism, or mutualism (if you had to choose one)?

7:44 PM  
Blogger Andrew said...

On agriculture:

I think it depends on which kinds of agriculture you're talking about. Cereal grains, for example, are annual plants that die at the end of each growing season anyway, so the human harvesting cycle corresponds to the natural lifecycle. Meanwhile, humans carry out the seed dispersal stage so that the plant no longer relies on wind to carry the seeds away. So that I would say is mutualism.

Domesticated animals I would say is more like controlled parasitism insofar as I don't see how it can be beneficial to the animal to be killed. (Keeping cows for milk I suppose could be more like mutualism if you treated the cows humanely.)

5:24 PM  
Blogger Henry said...

I can agree with that to some extent. I'm not sure that the qualifier-if you treated the cows humanely- is necessary. Their enjoyment of the arrangement doesn't change the bottom line of the equation. Also, even if they are killed before they die naturally, the species as a whole is benefitted if their reproductive success is greater than it would otherwise be in nature, so that would still make it a mutualistic situation. I guess maybe I can't see much difference between controlled parasitism and mutualism.
Hereis a bit on the lichen situation.

7:54 AM  

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