Love enduring

By Soncirey Mitchell
Reader Staff

Everything in this universe grows and changes in conjunction with and response to something else, metaphorically and literally. Humans are products of their environment, and whether that means personal idiosyncrasies or skin color, we build our bodies and minds around where we are and who or what we meet.

When talking about evolutionary adaptation, the obvious example is the Galápagos finches cataloged by Charles Darwin in 1859’s On the Origin of Species. Over millions of years, the birds evolved from one common ancestor into more than a dozen species, which slotted themselves and their offspring into ecological niches. Some developed sturdy, blunt beaks to crack nuts, while others grew long, skinny beaks to catch bugs.

Plants, on the other hand, have a far more direct and mutually beneficial relationship with their evolutionary partners, developing specialized fruits that attract and nourish specific animals. Plants that have learned to spread their seeds via bird droppings have evolved to become smaller, with thin, breakable skin to ensure birds can easily eat them. They also adopt bright shades that tetrachromats — animals that perceive red, green, blue and ultraviolet — can easily spot, such as bright red, blue or purple.

Adapting to mammals requires a different approach. Most have worse vision than birds and, therefore, rely on strong smells. These plants’ fruits develop in muted brown, yellow and green tones, and invest energy in strong protective skins and substantial, indigestible seeds that can pass through larger animals without being digested.

Peppers are an example of a fruit that adapted to suit the tastes of birds, yet, unwittingly, attracted mammals — i.e. humans — who spread their seeds in large quantities through agriculture. It’s the same desired outcome, just not the path peppers intended. Over the course of their evolution, peppers developed the bright colors that attract birds alongside capsaicin — the compound that gives them their spice — to which avians are immune. This was meant to deter mammals from eating them, but humans are odd creatures and like a bit of pain with their food.

These plants all have clear trajectories, but where do odd fruits like avocados fit in? Who, besides humans, spreads their unwieldy pits? Avocados, along with many other tropical fruits, are examples of evolutionary — or ecological — anachronism. They adapted to conditions that no longer exist, yet their evolution halted, rendering them relics of the ice age and beyond.

Such plants coevolved with now-extinct megafauna — shaping themselves to benefit, and benefit from, those long lost partners. Though the rest of the world moved on, the ghosts of ancient elephant-, sloth- and turtle-like beasts still haunt the genetics of their former foods. Without their partners, these fruits now fall to the ground and rot, with minimal dispersal, or are carried by water to less-than-ideal locations.

The theory of evolutionary anachronism stems from the work of ecologist Stanley Temple, later solidified by ecologist Daniel Janzen and paleoecologist Paul Martin, in the work “Neotropical Anachronisms: The Fruits the Gomphotheres Ate,” published in Science. (Gomphotheres are an ancestor of modern elephants.)

It was Martin who coined the term “megafaunal dispersal syndrome” to describe how these once great animals spread large seeds. He based the idea, in part, on elephants, which continue this ancient relationship with plants in Africa and, to a lesser extent, Asia.

In the natural world, it’s striking to see relative stagnation for thousands of years. The world these plants grew into is long gone, though they haven’t moved on from the beings around which they once molded themselves. In that sense, evolutionary anachronism feels like a tangible representation of love, and ultimately, grief. Even plants fighting to survive hold onto the past, growing in the same, inefficient way over thousands of years, carrying the dead into the present.

How beautiful, to be remembered in the descendants — in the very DNA — of someone you once cared for, and who cared for you. Even in nature, where every day is a struggle, bonds can transcend mere utility and become something lasting, despite the weight of ages.