OnlyHuman

"Parasites are not only incredibly diverse; they are also incredibly successful. There are parasitic stretches of DNA in your own genes, some of which are called retrotransposons. Many of the parasitic stretches were originally viruses that entered our DNA. Most of them don't do us any harm. They just copy and insert themselves in other parts of our DNA, basically replicating themselves. Sometimes they hop into other species and replicate themselves in a new host. According to one estimate, roughly one-third to one-half of all human DNA is basically parasitic.

Once you broaden your definition, you can label many things parasites. A lot of people ask me, "Do you think humans are parasites?" It's an interesting idea and one worth thinking about. People casually refer to humanity as a virus spreading across the earth. In fact, we do look like some strange kind of bio-film spreading across the landscape.

I think it's a pretty good metaphor. If the biosphere is our host, we do use it up for our own benefit. We do manipulate it. We alter the flows and fluxes of elements like carbon and nitrogen to benefit ourselves--often at the expense of the biosphere as a whole. If you look at how coral reefs or tropical forests are faring these days, you'll notice that our host is not doing that well right now.

However, as you can probably tell from my talk, I don't think there's anything all that bad about being called a parasite. Parasites are very sophisticated; parasites are highly evolved; parasites are very successful, as reflected in their diversity. In fact, I would say that we may be parasites, but we're not very good ones. Successful parasites do a very good job of balancing--using up their hosts and keeping them alive. It's all a question of tuning the adaptation to your particular host. In our case, we have only one host, so we have to be particularly careful."

- Carl Zimmer, Columbia University

Comments

[richard kearns]

my dear--i think you are confusing parasites and symbiotes

parasites just use up their hosts

symbiots feed off of and take care of their hosts

[Aatom]

Main Entry: par·a·site
Pronunciation: 'par-&-"sIt
Function: noun
Etymology: Middle French, from Latin parasitus, from Greek parasitos, from para- + sitos grain, food

3: Something that resembles a biological parasite in dependence on something else for existence or support without making a useful or adequate return

It would be hard to argue that this definition doesn't succinctly describe our relationship to the planet.

[richard kearns]

actually, it wouldn't be hard at all to argue another case, but i actually like definition #3 below myself (2b would be second place):

parasite:

1. Biology. An organism that grows, feeds, and is sheltered on or in a different organism while contributing nothing to the survival of its host.
2. a. One who habitually takes advantage of the generosity of others without making any useful return.
b. One who lives off and flatters the rich; a sycophant.
3. A professional dinner guest, especially in ancient Greece.

[Latin parasītus, a person who lives by amusing the rich, from Greek parasītos, person who eats at someone else's table, parasite : para-, beside; see para–1 + sītos, grain, food.]

[Aatom]

lol. i love 3. as well.

[kelly]

im the artist of the image you call "only human"...you might at least give me credit for the image since u seem to have lifted it without my permission

[Aatom]

More than happy to give credit where it is due, Kelly! I was very taken with this image two years ago when I posted this. It's messy, haunting, and slightly amusing. Just like us! Please accept my humble apology for not giving a full credit initially. I should have visited your site at the time, but I have now and absolutely love your work. Anyone reading this should visit kellymoore.net to check it all out...