Planet of the Plants

The War of the Plants

What would it do to our overinflated sense of human exceptionalism, I wonder, if we were to suddenly realize we're just foot soldiers in a war among the plants? A war which in its latest incarnation has been going on for 65 million years?

Certainly, the answer to the question of how animals evolve and what pushes them to evolve, what dictates the shape and function of everything from bees to human beings, is generally speaking answered with one word: plants. The effect of flowers on human evolution, and the effect of grasses on the existence of modern human culture, is pretty much absolute. When flowering plants started using fruit as an enticement, numbers of groups of early mammals including those that would become the primates, switched from primarily eating bugs and roots to primarily eating fruit. This happened because plants wanted to disperse their seeds and feeding mammals fruit turned out to be a highly efficient method of getting seeds distributed far and wide, with a conveniently supplied source of fertilizer to boot in the form of animal dung. Primates developed their upper body strength and hands to gather fruit, and developed color vision to see when it was ripe. When grasses started making inroads on the forests, our early ancestors moved into this new environment and started hunting, developed an upright stance so they could see over the tall grasses, and eventually grasses would supply the few species of grains upon which civilized life utterly depends: wheat, rice, maize, barley, oats, millet. For animals, the reason why we are here at all and what form we take is answered on the whole with one statement: plants made it happen.

Plants alone possess the power to gather together CO2 from the atmosphere, water from the environment, and sunlight from outer space, our nearest star, and put them together to make packaged food energy in the form of carbohydrates, and it is upon this food that all animal life on Earth depends and which powers our cars and heats our homes. But despite their calm outward demeanor, plants wage wars on each other and sometimes on we animals that would make the machinations of human kingdoms seem tame.

65 million years ago, Earth was the planet of the forests. Forests covered the planet, even in Antarctica. Trees ruled everything, and life in the understory struggled for what scraps of light the trees let fall from their table in the sky. The Cretaceous-Paleogene extinction event that wiped out the dinosaurs also burned the forests, and for awhile only ferns could populate the landscape, followed by conifers. Trees evolved from flowering plants soon returned to something like their former strengths, but many had become extinct and many insects upon which the plants depended became extinct. This brief setback in the Kingdom of the Forests was capitalized on by a new kind of plant: the grasses. The grasses encouraged fires from which they could recover quickly but forests could not, and while grazing animals evolved to eat the grasses they also ate the tree sprouts which attempted to colonize the grasslands, and so largely permanent grasslands arose. Early hominids left the forest behind to try to make use of this new terrain, and eventually spread over the entire habitable globe. And then over 11,000 years ago, a type of grass allowed humans to stay in one place long enough and build high enough populations to build what are now the oldest human-built structures in the world, the ruins of Gobekli Tepe in Turkey. That grain, was wheat, and when humans found a mutation of wheat that would allow it to be gathered with much greater ease than the non-mutated form, they and that wheat created the agricultural revolution. Which meant that this wheat spread to grasslands all over the world.

Today, human civilization is utterly dependent on grasses, and the majority of the other foods we eat come from a very limited number of plant families. The grasses of course from whence we get the grains but also bamboo, the Rose family, the Cucurbitaceae (squashes, melons, pumpkins, gourds), the Nightshade family (tomatoes, potatoes, peppers and also tobacco), the Brassicaceae (cabbage, broccoli, brussel sprouts, radishes, turnips), and a few others. From an evolutionary point of view, the association of these plant families with human beings has thus far been an unqualified success. If anything were to happen to these few plant families, civilization as we know it would cease and maybe the human species as well. The grasses have benefited in another way, as humans cleared the forests to plant more grain and vegetables.

So yes, from an evolutionary point of view we're basically just foot soldiers in a 65 million year old war between the grasses and the forests. ;) And it is not impossible that one day the tide could turn and the forests cover the Earth again. And yet how much time does your average non-farming human being spend thinking deep thoughts about plants?

They should, you know? There has been new research showing a deeper level of communication among plants than we have previously thought. Next time you take a walk in the park think about this: all those plants, far from being inert landscaping, are talking to each other and fighting slow wars with each other all the time. We've found out they have an analogue to the animal nervous system. It's not like ours, but it is there none the less and capable of billions of connections. Just because we don't understand it, doesn't mean they don't have some kind of no doubt very different awareness. We are only scratching the surface of understanding the higher functions of plants. ("Shhh, the humans are coming, act dumb...") ;)

The rise and fall of plant kingdoms made us in the beginning and can unmake us. It was they who turned this world in the beginning from a hostile irradiated moonscape with a toxic atmosphere to the living world we see today. It's their planet really, we're just along for the ride. ;)