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Wednesday, March 28, 2007

The Largest Single Organism on Earth

The largest known organism is not some giant squid or other cephalopod. It's a stand of quaking aspen in Utah known as Pando. What seem to be individual trees are actually just the visible expression of a gigantic underground organism. Every "tree" is connected via the root system. The individual "trees" are genetically identical. (Erroneously referred to as "clones.")

The total size and weight of this organism isn't known with certainty but it's surely more than 6,000,000 kg. The Wikipedia article mentions that Pando is probably the oldest known organism as well, dating back 80,000 years. I'd like to confirm this, if possible. Does anyone know how accurate this date is and whether there is anything older?

Lots of plants are bigger than cephalopods. There are even some mushrooms that are bigger!


  1. Interesting. I would have thought some fungi would be competitive, since they can extend for miles underground. But they're probably not as heavy.

  2. The costal redwoods should be competitors for the largest and oldest individuals. Most of the time they also propagate clonally through shoots from roots, just like Aspen.

  3. "Largest organism" depends what dimension you're measuring. There are areas of genetically-identical honey fungus that measure up to ~9 km^2, which is about 20 times the size of this poplar stant. The difficulty is in proving that it's a single organism, and not a set of isolated clonally-identical colonies.

  4. Second thought: I wonder if there's seeding of stem cells from one end of the colony to the other. If not, you'd expect that mutations would accumulate gradually (though obviously very slowly) as the colony spreads.

    How wide does the colony have to get before the opposite edges become effectively isolated from each other?

    If the stand spreads over into a different type of soil, would you select for mutations favouring growth in that soil?

    Might it be possible to have speciation within a single organism, given _enough_ time?

  5. What is an organism?

    Proposed Definition Of Earth Organism And Of Gene.

    An Earth organism: a temporary self-replicable constrained-energy genetic system that supports and maintains Earth's biosphere by maintenance of genes.

    Gene: a primal Earth's organism.


    Dov Henis

  6. Yes, I have read that there is a genetically identical fungal entity (1 or more indivs.?) that lives in the soil of 4 or 5 COUNTIES --Manistee & others--in NW Michigan. It might be the largest in area, but I'm guessing it lives in a narrow band of depth--almost like a strata.