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Episode Extra: Behemoths of Biomass

(This post helps explain some of the science in the latest episode of my YouTube show, which is called, you guessed it, It’s Okay To Be Smart. It’s impossible to get all the details into a few minutes, so I dig into the them here. Watch the episode here if you haven’t already. Seriously, watch it already!)

Lots of the “scale of life” stuff that I talked about in my latest episode “Life by the Numbers” dealt with the mind-boggling multitudes that make up populations of things like birds, bacteria and viruses. But being numerous isn’t all there is to success. What about enormous single organisms?

Individual life forms may not have much influence on the world around them all by their lonesome selves, but when they come together on enormous scales like billions, trillions or quadrillions they can have huge influence their ecosystems because of … well, their sheer numbers. Trillions of bacteria crawling around in forest soil possess an incredibly diverse set of genes that they can share and transfer between each other like salesmen trading business cards. That drives evolution into the fast lane. These “big number” populations can also eat a lot, or provide food for a host of other organisms, as ocean viruses do as their infected dead sink to the bottom of the ocean to feed hordes of tiny creatures. Circle of life, man.

Now for the behemoths. Large single individuals can also have huge advantages from being large and independent, but that brings its own set of risks.

Take the Aspen tree grove named Pando that I talked about in the video. It gains an advantage by being one single, genetically identical, physically connected organism. It is literally a single tree that looks like tens of thousands. Wrap your mind around that. If one side of the grove is near water or minerals, it can transfer those nutrients to an area of grove that is dry or in less fertile soil, like a big city plumbing system. This underground connection is also a defense against forest fires, because all the above-surface parts can burn away and new trees can grow back quickly. Environmental adaptation, folks!

Several people didn’t like how I compared an underground fungus (it lives in Oregon’s Malheur National Forest) to the weight of 75 space shuttles. Well, there’s no number I can give you that will make any sense to our petty human brains. How about 7,000 tons? What’s even crazier is that the underground fungal web is nearly invisible. We’re used to seeing the fruiting bodies of fungi, those mushroom things. But it’s the threadlike hyphae and mycelium that reach like fingers through the forest floor, digesting dead plant matter so that it doesn’t pile up over the treetops (because it would, seriously). It’s a massively interconnected fungal buffet, and these decomposers help keep an area the size of 1,600 football fields clear.

Unfortunately, being genetically identical means they are extra-sensitive to disease and environmental disruption. That’s why WE need to be so careful about how we treat these giants of biomass.

So these big boys and girls can serve as cornerstones of ecosystems, be incredibly resilient, and attain great mass and reach because they are a single, large organism. But this is also their Achilles’ heel, and makes them incredibly sensitive to the destructive forces of man, beast and bug. Being bigger and broader is an immense accomplishment in terms of evolution, but evolution never reaches perfection. This is proof of species success, but success is perhaps never complete in the living world.

How do you think “bigger” compares to “numerous” in species success?