What follows in these pages is my attempt to explore those twining threads and tendrils in life's ongoing story. I had to accept at the outset that this drama is flawed and fraught. I am, after all, only human. Our curiosity about other living things is limited by the array of senses we've been granted through our own evolutionary lineage. I can't see in ultraviolet colors. There are innumerable pheromones I cannot detect or respond to. Electromagnetic fields may as well be invisible magic as far as my body can actively perceive. If I had any of these abilities that are common to other animals, my insights might be different. That's hardly all. I'm a large mammal— technically megafauna. If I were the size of a bacterium, a mouse, or an elephant, my thoughts on plants and what they are would be shaped by my size and other aspects of my biology. Even considering some of my most direct interactions with plants during mealtimes, the plants I eat come from farms and have been cultivated over centuries to often be seedless, larger, or tastier than the original species. Such idiosyncrasies in experience and perception surely shape the story, knowledge that anyone fond of science eventually has to grapple with. We exist within a natural reality that we can question, investigate, and find inspiration in, but even what we know is not the whole of what exists.
It's taken time for me to learn and appreciate all these limitations, and more, affecting even the questions I might think to ask. Such constraints give form to our wonder, and that is what I wish to share with you. Within these pages, I hope you encounter living things you've never heard of before today as you slide from one window to the next, and each is an illustration of a broader story. Plants act as our focal points, mainly because they make such beautiful examples for considering how they've changed the world and been shaped by it in turn. The root system beneath each tale is the deeper story of how the relationship between plants and the rest of our planet has unfolded, the constant process of making and unmaking that unfolds as the green shoot of life continues to stretch from its point of origin. What I mean by "when the Earth was green" is not some irretrievable past or a denial that, despite our efforts, there is a great deal of green around us today, but thinking of key moments that plants have changed the nature of nature itself just as we tend to pay special attention to the great springtime blooms when the first leaves unfurled all around us are so impossibly, vibrantly verdant that I can't help but smile when I notice the hills around my home burst with color. When I see those shades, I think of all those varied lives and how many different ways of existing there are. If we take a moment to find connection with and live through lives unlike our own, we can find worlds within worlds just like rows of petals in a flower. Happy accidents, chance encounters, and nature's persistent habit of growing outside the boxes we try to organize it within have created relationships of incredible, transcendent change, moments in a broader tale that will keep unfolding for as long as there is an Earth. A bloom is the happiest of accidents.
CHAPTER ONE
SEX IN THE SHALLOWS
1.2 billion years ago
Arctic Canada
Little red threads waft back and forth to the slow rhythm of the waves. Each is so incredibly small that every wispy strand is anchored between individual pieces of crushed stone and quartz, relying upon what can only be a tenuous hold on the ever-shifting sea bottom. They can do little else but dance to the time called by the sea.
To pick out any single filament from the mass would be extremely difficult. These living things, stacks of cells that would seem to barely reach above the sediment, only span a couple of microns each, gathered around each other in organic strings growing from the tiny spaces between sand grains that were once stone. They make their own food by using energy from sunlight to rearrange organic molecules into forms able to nourish them during their sedentary existence. Despite their humble appearance, however, the threads are something novel on Earth. In a world of singular, self-contained bodies, the algae's cooperative cells can carry out different functions—whether that's holding tight to the substrate or sending a new generation out into the world. Their messy clumps are a foreshadowing, in miniature, of forests that will stretch both into the air and deep below the ground. The strands are not Earth's first photosynthesizers, nor are they technically plants. The multicellular strings are something between, a new expression of forms that have long existed but arranged in such a way that each part of the organism has its own role to play. The filaments have been shaped by the shifting demands of natural selection as well as a surprise co-habitation, a history in which the barriers between one living thing and another have become so permeable as to almost be intimate. And for the moment, the meek little algae are among the most complex life-forms among what is still—and will always be—a world densely populated by microbes.
So far as sheer longevity is concerned, organisms like these red algae will persist across incredible spans of time. Bangiomorpha, as they will eventually be named, wouldn't look out of place in a twenty-first-century tide pool. But all those other organisms that we might associate with a trip to the beach are still a long, long way off. During this Mesoproterozoic time, there are no shells in the sand. Nothing large enough to be visible to the human eye swims through the water. No fish, no cephalopods, no bivalves, nothing at all that we would recognize as animal lives in these waters—or anywhere else on Earth. The earliest recognizable animal life, sponges that will form their own anchors to the ocean bottom, are still over 400 million years off in the future from this point in prehistoric time.
