Faculty in First Person: David Cowles

The Distinguished Faculty Lecturer for 2024 explains how we can all live better through symbiosis

by David Cowles '78, professor of biology

The Bible tells us that “God is love” and to “love one another” (I John 4:8, 11). Like many things in our fallen world, however, modern science has tended to mainly notice the predatory and competitive aspects of biological and human communities instead.

As a young biologist, that led me to wonder how the world might look if it followed God’s principles. That turned my focus to mutualistic symbiosis, a situation in which several creatures do indeed seem to “follow a different drummer” by working in long-term beneficial cooperation with each other.

Over the years, I have discovered that this type of symbiosis is widespread and have noticed several important principles:

Symbiosis can be especially important for young individuals.

One of my first forays into symbiosis, under the tutelage of the legendary Larry McCloskey here at WWU, was a study of the giant green anemone. The anemone, which lives in coastal tidepools and eats mussels dislodged from the rocks, isn’t itself really green. Instead, its cells are jammed full of green algae that benefit from this safe place to live. In turn, the algae use light energy to produce food to pass on to the anemone.

In my research I discovered that large anemones, which monopolize the bottom of tidepools and catch most of the mussels, get only a little help from their algae. However, the small anemones, which live on the less-advantageous side walls, receive a large portion of their total food needs from the work of the algae.

Human communities can be that way too. I well remember my neighbor Myrtle in my childhood community, who even after a terrible, crippling accident that left her in constant pain, thrived by maintaining an open-door policy to neighborhood kids. She became an example of agape love to all of us that visited her and were blessed by her attention and wisdom.

An educational community such as that here at WWU centers on that kind of symbiosis! I imagine that every one of us can think back on multiple special professors that sharpened our thoughts, stimulated our growth, and helped us focus in the right directions.

Symbiosis can be a powerful community-organizing and stabilizing force.

One such symbiosis is that of mycorrhizae: long strands of fungal tissue that extend for many meters through the soil and penetrate into the roots of nearby plants. These mycorrhizae enhance the health, growth, and development of the plants they partner with by increasing their ability to obtain water and nutrients from the soil. Furthermore, the mycorrhizae frequently connect to many different plants at once, forming a “wood-wide web” and facilitating exchange of nutrients and other materials among the plants connected to the web.

In a similar way, a huge number of microbial symbionts live within and upon us, not only defending us from disease but affecting our physiology, development, and even moods in a host of previously unsuspected ways. New ways these symbionts affect us are being discovered almost every week!

The cooperative organizations we as individuals belong to also enhance our well-being. Think about your local pastor, friendly grocer, firefighters, and police. All of them are symbiotic links that enhance our quality of life.

Even small, scarcely visible symbiotic relationships can powerfully shape communities.

Scientific papers were abuzz recently with the discovery of the surprisingly broad reach of a mutualistic symbiosis. Acacia trees, lions, elephants, and grazing animals are iconic in the broad sweep of the African savannah. Many of the acacia have a tiny symbiont: the acacia ant. This ant lives within acacia thorns and the tree produces special small structures to feed them. In return the ants clean around the tree and are tiny sentinels that nip anything that grazes on the leaves.

Recently an invasive ant that outcompetes the acacia ant and takes over the tree has appeared. The new ant does not so diligently nip grazers. In those areas elephants graze the trees. Their grazing is violent and the trees are quickly broken down. That provides hardship for local lions, who normally hide behind the trees to get close to their favorite prey, zebras. Zebras are now multiplying, lions are not doing so well, and the savannah is turning into a grassland. And all because of the loss of a tiny ant!

Think about those people in your life who make a small, consistent difference and enrich the textures of your day. The older gentleman who greets you with a hearty “hello” on your morning walk, the lady who maintains beautiful flower boxes just down the street, the kids across the road who give you a bright smile while they ride their bicycles past. They are symbionts too! And what would our lives be without them? So go ahead—be a symbiont yourself in the lives of those around you by brightening the corner where you are.