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Life is chemistry. From diatom to Diana, life is not a magical imbued trait, is a process of the physics of our universe. The precise and convoluted chemistry of life requires specific physical and chemical situations. And this planet has a dizzying variety of such circumstances that, over millions or even billions of years, living chemical systems have evolved to thrive in.

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Our minds have made an error.

We look at these gliding beauties of marvelous complexity and we think that they...and we...are something of our own. That life is a kind of indescribable magic….

Even Darwin said, in his gorgeous conclusion to On the Origin of Species, that life was something that had been “originally breathed into a few forms or into one.” This completely understandable perspective is nonetheless an error. There was no way for Darwin to know it...but life….life is chemistry. From diatom to Diana, life is not a magical imbued trait, it is a process of the physics of our universe.

The precise and convoluted chemistry of life requires specific physical and chemical situations. And this planet has a dizzying variety of such circumstances that, over millions or even billions of years, living chemical systems have evolved to thrive in. But one thing that is always necessary is energy.

A system without energy doesn’t just not have life, it doesn’t have chemistry. And so, the story of life is the story of captured energy. These are Oscillatoria a form of cyanobacteria .

Every second of every day, for billions of years, the sun has been exploding, sending energy to the earth in the form of sunlight. And on the other end— or really, on our end—are photosynthetic bacteria like these that use the energy of that light to construct chemical complexity. These Oscillatoria are gliding toward that light so that they can harvest the energy they need to produce a kind of chemical so important...that you will probably be surprised to find out that it’s just sugar.

Oh sugar, such a chemical marvel. Just carbon and hydrogen and oxygen...but an evolutionary innovation so fundamental that it remains a primary source of nourishment for even the most advanced living things. You may have seen this beautiful filamentous algae called Spirogyra floating on the surface of water, where it also takes advantage of sunlight to produce its own food.

Oscillatoria and Spirogyra are for self...troph for nourishment. In the world of ecology, we call these self-nourishers the primary producers. They are where it all begins.

Primary Producers can turn the fundamental, inorganic components of their surrounding environment into food. In the case of photosynthetic (or, phototrophic) organisms, the energy component of that surrounding environment is light. There are also physical components...they need carbon dioxide and water and nitrogen and phosphorous for building materials, but light is the energy.

This is the first way organisms get food...they make it. And most autotrophs use light...but not all! There also lithotrophs, for example, that use chemical bonds in minerals to thrive.

Unfortunately, we don’t have any footage of just...more spirogyra for you! And like plants in our macroscopic systems, autotrophic microbes are the starting point of the story of captured energy. Because, in their bid to hold onto and use that energy, they themselves become balls of stored energy.

Not just in their energy storage systems like their sugars, but their whole selves are bags of entropically unstable complexity, ready to fall into randomness the moment their chemistry fails. I think we have to understand here that randomness is the natural state of the universe. Not because of some inherent evil, but just because there are literal trillions of random ways for atoms and molecules to be scattered about, and a vanishingly small number of ways in which they will be organized.

And so, fighting randomness...that is the cause of life, and that fight both requires energy, but also, definitionally, stores energy. Because an organized state tends toward disorganization, the path down that hill is one that releases energy. And as that energy is released, it can be captured.

And if it can be captured by another organism, it can be exploited. And so we have our second system living organisms use to stay alive. They don’t make their food...they eat it.

Single-celled eukaryotes, also called protozoans, dine on autotrophs, digesting their organic components to supplement their own bodies with the nutrients and energy they need to grow and survive. And from there, nature weaves the complexity of the food web, transferring nutrients and energy through this network of organisms consuming other organisms. Protozoans eat protozoans, and sometimes even a few metazoans— the microscopic multicellular organisms like rotifers, water bears, or fat flatworms.

And then you get to metazoans that eat protozoans, like Daphnia, which in turn gets eaten by fish, the microscopic now transitioning into the macro. These eaters consolidate the energy, not just keeping themselves alive, but feeding the more complex chemistry, pushing themselves further and further from randomness...further and further from the equilibrium state. But in the end, no matter what, life neither big nor small lasts.

Eventually, through random chance or wear and tear, the chemical systems maintaining this far-from-equilibrium state break, and the living chemistry ends. And so we have our final opportunity for energy transfer. The last link in the stored energy chain, the decomposers.

As microbes and plants and animals alike die, they decompose into the environment, their bodies broken down and recycled by organisms like this Peranema, which is usually found among decaying organic matter. Here, you can see its mouth, called the “rod organ,” through which it takes in bits of decomposing matter, and sometimes just other organisms, and eats them, converting them into carbohydrates that it stores in those shiny paramylon grains. Though these decomposers come at the end of the food chain, well after the sunlight that started it all, they are still surviving on that stored energy originally flung out from two atoms fusing in the core of the sun.

And, of course, the role they play in our ecosystems is still vital. As they break down once living organisms into their chemical building blocks, they release those nutrients back into the environment, ensuring that those building blocks are available to the autotrophs that will begin the cycle all over again. As we delve into more and more ecosystems, the vast number of factors that have shaped a microbe’s evolution become more and more apparent.

But one thing remains consistent, the chain of stored energy...the primary producers...the eaters...and the decomposers, sustaining the chemical system that keeps them complex...the energy that holds them together, and that is holding you together right now, preventing you from simply falling into randomness. Thank you for coming on this journey with us as we explore the unseen world that surrounds us. and thank you, also, to all of these wonderful people for supporting this channel on Patreon and making it possible for us to do this. If you want to see more from our Master of Microscopes, James Weiss check out Jam and Germs on Instagram.

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