The first farmers

To understand the importance of biodiversity in agriculture, it’s necessary to understand something about the history of agriculture itself.

These are modern farmers, but they use time-honored methods to harvest their crops. (International Crops Research Institute for the Semi-Arid Tropics.)

Agriculture didn’t just pop out of the ground on its own some two million years ago, when human-like creatures first roamed Earth. The word itself implies that humans were involved — “agriculture” comes from the Latin for “field” plus “cultivation,” which means preparing the land for the growing of crops. And it took humans a while to get around to that.

For centuries they kept themselves alive by being what the experts call “hunter-gatherers,” or those who hunted down (or fished for) and killed their animal food, and who gathered the plants that they liked to eat and that they found, through trial and error, didn’t poison them..

A change of technique.
They were good at hunting and gathering (if they weren’t, they went hungry), but they felt a need to change their techniques about ten thousand years ago: They began to cultivate their own food. Perhaps this was because human population had grown to the point that people needed to supplement their wild food with home-grown (“domesticated”) plants and animals. Historians debate constantly about just how and when all this came about, but it seems that people took to agriculture because it produced a more reliable supply of food. It also allowed larger numbers of people to live together in communities — first villages, then towns, and later cities.

The shift also forced people to dramatically alter their roaming ways. A farmer had to stay in one place to tend crops and livestock, rather than live the life of a wandering nomad. The birth of agriculture meant a new and very important emphasis on genetic diversity. The farmer now had to decide which plants and animals best served her or his purposes, and then to save the seed from those plants for next year, or to mate the best animal with another. Rather than just accepting what Nature made available, in terms of a wild animal that had the bad luck to wander into the farmer’s ambush or a wild plant that seemed nourishing and tasty (or at least not harmful), humans began to use diversity to produce the food they liked best.

What would you do if you were deciding which plants’ seeds — maizes, for instance, or beans — to keep and use next year? You would undoubtedly be influenced by a few basic qualities, such as how the food tastes (does your family like it, or does Junior say “Yuk” every time it’s served?) How about the time it takes to grow to maturity? (The longer it stays in the field, ripening, the more vulnerable it is to insects, diseases, and marauding animals and even your hungry neighbors. A shorter growing time might be better.) Can the plant take intense heat or scarcity of rain or soil with a lot of salt in it? (If you live in a hot, dry climate or on degraded land, this can make a big difference.) And on and on, right down to the color and texture of the seed. There are some parts of the world where people prefer a white, smooth bean, and others where they like a brown, wrinkled one.

The earliest plant breeders.
The farmer, in picking and choosing what to plant next time, and the time after that, and the time after that, was creating what agricultural scientists today call a landrace. Put in simple terms, a landrace is a cultivar (a variety of a plant that has been cultivated) that is adapted to local environmental conditions. One scientific study refers to landraces as “the products of centuries of planting, selecting, and replanting by farmers.”

The farmer’s a she. Chances are, when we speak of “the farmer” we’re speaking about a woman. We know very little about the earliest agriculturalists, but it’s quite likely that the women in a community were the ones who planted seeds, cultivated the crops, and gathered the seeds for next season. That holds true for modern times, too; there have been estimates that the majority of the world’s farmers are women. (International Plant Genetic Resources Institute)

Landraces may not look pretty or taste good to everyone, and they might not be in demand in markets or fancy restaurants. But because they are descendants of ancient crops, landraces can be treasuries of genetic diversity. They may contain genes that, when combined with genes from other varieties, produce characteristics that are much desired by the marketplace, the farmer, and the consumer.

This means they are useful to farmers and scientists in breeding what are called “improved” varieties — crops that can handle disease, or insect damage, or short day length, cold nights, high altitude, or any of a number of environmental conditions. Or they may be especially rich in proteins or the small traces of vitamins and minerals (“micronutrients”) that are essential to keeping us healthy.

Whether they thought of it or not, these early farmers were the first plant breeders. Plant breeding has been defined as “the science of manipulating a plant's genetic composition,” and that is exactly what the early farmers, in selecting plants with favorable genetic characteristics, were doing. Today, that form of farmer-supervised plant breeding still goes on, but it has been supplemented by breeding done by men and women in white laboratory coats and on neatly-arranged experimental fields.

Biological diversity, then, is essential to the continued growth of food, and that is essential to the continued growth of the human race. The diversity may be easy to see — the veggie aisle in a supermarket may display a diversity of green, red, and orange sweet peppers, or onions that can sting your tongue, alongside onions that are advertised as sweet — but it also can reside out of your sight, in the genes of the plant or the seed that produced it.

A lot of this diversity didn’t just happen, either as the result of farmers messing about with landraces or professors making decisions in laboratories. (For a look at one of history's most significant experiments in agricultural diversity, see the page on the Green Revolution.) The diverse sorts of food we eat owe a lot to where they first grew, as wild plants. Certain parts of the world have contributed heavily to this storehouse of genetic material. They are called centers of diversity.

Take a side trip to centers of diversity

What did Gregor Mendel prove with his peas?

Next: Mendel and his peas — Agriculture home page — Glossary — Site map
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