Are Parasites Singing Their Own Unceasing Song Of Life?
Donald A. Windsor
Well, parasites may not be singing, but they sure are showing off their most visible presence – biodiversity.
James Lovelock referred to the infrared signal of the oxygen-methane disequilibrium radiating from Earth's atmosphere as an "unceasing song of life".
"This unceasing song of life is audible to anyone with a receiver, even from outside the Solar System." (1).
If Lovelock's statement is correct, then this song would indicate life on any extraterrestrial entity.
After such life is found, perhaps it could reveal whether parasitism is, or is not, a universal property of life. I suspect that it is.
Here on Earth, our life exhibits parasitism. But, what would life look like without parasitism? I suspect that the signature hallmark of life is biodiversity. But biodiversity can result from life adapting to environmental forces, such as competition, predation, habitat, and climate.
Parasites enhance biodiversity by thwarting monocultures. Therefore, the absence of monocultures on extraterrestrial entities could be a signature of parasitism.
However, how would a monoculture be recognized? On Earth we have no naturally occurring pure monocultures; they exists only in labs or buildings. Our so-called monocultures, such as with agricultural crops like corn and wheat, always have other species living among them.
Here is a handy metric that I propose. In a monoculture, the number of individuals of one species is at least 1 magnitude higher than the total number of individuals of all the other species combined, in the same area.
For example, if a bean field had 10,000 individual bean plants, then it would be a monoculture if the total number of individuals of all the other species in that field was under 1,000, a difference of 1 order of magnitude.
This metric would not be able to compare macro-species with microbial species, because the microbes would always outnumber the macros. However, it may be useful in comparing a monoculture of a microbe with other microbial species.
So, while the unceasing song of parasitism may not be a song, it may be an image visible to anyone with a viewer.
1. Lovelock, James. The Ages of Gaia. A Biography of Our Living Earth. 2nd Edition. New York, NY: Oxford University Press. 2000. 268 pages. Quote on page 7 of the Introductory.