OUT OF SIGHT, OUT OF MIND

One of the surprising, but moving experiences of my life was one night when I first watched a cell actually divide in two. We all have learned that cells do this. I had seen television specials, documentaries and teaching films showing cell division. So it was surprising to me that when I actually saw the event myself, I found it profoundly emotional. Maybe that’s just me.

Later I was similarly affected in a class where I had students place corn pollen in a special solution, and we watched the pollen tubes grow before our very eyes. This growth can occur in just minutes and is easily observed under a microscope. Corn pollen can grow up to twelve inches to reach a plants ovary. As I sat at a microscope and watched a mystery of life occur before my eyes, I was surprisingly moved.

Pollen is normally deposited on the stigma of a flowering plant, a structure rising some distance above the ovary (in human terms). The pollen tube grows down to the ovary and bursts, releasing two sperm cells onto the ovary. One sperm cell unites with the ovary to create the embryo. The other sperm cell unites with a special cell to form the endosperm. The endosperm will become the food supply that nourishes the new embryo and/or humans in many instances. We intercede and eat the endosperm of such as plants as wheat, barley, oats, corn, peaches, pears, cherries, apricots, grapes, berries, cucumbers, tomatoes, peppers, and more.

Getting pollen to the stigma is a bit of a trick for plants since they are generally immobile and can’t get together in some central location to socialize. The process is called pollination, and generally it occurs in one of two ways: either by wind or by an intermediary animal.

Bees are the best known of these pollinators, although not the only ones. And while most folks think honey bees are the best pollinators, this isn’t true. In fact, honey bees are not even native to North America. They were first brought by the early pilgrims and quickly spread out to fill the continent. But prior to that there was a rich population of Native bees on this continent that pollinated everything necessary very efficiently. In fact, North America has one of the richest populations of these solitary bees in the world.

There are approximately 4000 species of Native bees in North America. These bees do not form large colonies with honey stores like honey bees do. Instead, each female mates and sets about establishing her own nest. She finds an appropriate site and lays her eggs one at a time, provisioning each egg with pollen and nectar for the year. After laying her last eggs she dies. But the new generation lives invisibly within her nest for the remainder of the year. This generation will hatch out at appropriate times the following year to complete the cycle.

Many of these bees are extremely local, being found in only specific regions. Some are tied to the life cycle of a single plant and are found only where that plant thrives. Others are more general and widespread. Many of them nest in the ground. Others nest in hollow stems, or old beetle holes in logs. Many are very small, significantly smaller than honey bees. They are not even colored in what most of us would think typical bee coloration. Because they spend most of the year inside a nest, are active for only short periods, and may not look like ordinary bees, they are invisible to most lay people.

However, “by their fruits ye shall know them”. Native bees out-pollinate honey bees by tremendous amounts. Two hundred and fifty native bees can pollinate an acre of apples. It would take a honey bee hive of 50,000 honey bees to serve the same orchard. Native bees are the hidden pollinators. Often, when they are not present, crop yield is poor and losses are attributed to weather or disease, when instead it is a lack of pollinators. These little creatures are generally out of human sight, and out of human mind.

Symbiosis II

When a relationship no longer provides mutual benefit, it is dead.

SYMBIOSIS

Sometimes significant truths are hidden in plain sight.

You might be surprised to know that there are more parasites than free-living animals. Every free-living animal that has been carefully examined has had at least one animal that lives exclusively in, or on, the host. This fact alone, if borne out by continued studies, would make the number of animals living on other animals equal to the number of hosts. But in addition, most animals host much more than one other animal that are shared with, perhaps, numerous other hosts. So if there are a million free-living animal species, there must surely be at least a million other animals that live on them.

Of course, “parasite” may not be the correct word for all of these animals, but that is a semantic discussion, not relating to whether such animals exist in large numbers or not. I may discuss that very issue in a later essay.

Another group of animals that live exclusively in, or on, another living species are the pollinators. The biological connection between the flowering plants and pollinators is so strong that one simply would cease to exist without the other. The majority of flowering plants require an animal to move pollen from one flower or plant to another. But the pollinator requires the flower to supply pollen and/or nectar, absolutely essential to the pollinator’s survival. The two are entwined in an ecological dance that is absolute, and mutually dependent.

Approximately a quarter of a million plants, and three quarters of a million insects, has been described by scientists on the earth today. Together this accounts for fully two thirds of all known organisms on our planet. This is not an accident. These two groups are interdependent for food and reproductive services. There are literally thousands of partnerships between insects and plants. Most are fragile, many are very specific, and often they include third party arrangements. If one partner is lost or diminished, the others will also be lost or diminished. The world does not consist of species. The world consists of ecosystems and partnerships.

The German mycologist (fungus specialist) Heinrich Anton de Bary coined a term as long ago as the late 1800’s for these kinds of relationships: symbiosis. He defined them as “the living together of unlike organisms”. This term has been modified over the years to have slightly different meanings. But I think the original meaning captures a concept that has not been properly appreciated in scientific circles.

Important common phenomena are sometimes underappreciated, while the new, the esoteric or the scandalous captures our attention. In the years since Darwin, evolution has become a dominant scientific principle. “Survival of the fittest” is a common metaphor. But what if the “fittest” doesn’t mean the strongest, or fastest or best adept at hiding, or most prolific as is popularly thought? What if “fit” actually means the ones best at living together? There are literally million of examples that this might be the case. And the pollinators may be the best example we could study.

The study of symbiosis may be one of the true unifying principles of Biology, and one that could more productively be applied to human existence than the results of social Darwinism.