Until recently all living things on the earth were evolving. Over millions of years this has meant that life has become as diverse as an ant, a crocodile, a peanut, a sea horse, a virus, a pine tree and a human. Evolution has meant that some forms of life have survived ice ages and desertification; constantly adapting to change by natural selection and the survival of the fittest.
For the last 50,000 years or so, as humans have been evolving and changing, so have the foods we eat. Humans have also taken some seeds with them on long journeys and planted them in new lands. The new conditions have meant different characteristics have developed. Land masses have shifted and animals and plants have become separated and consequently evolved differently. All the time large gene pools have supplied enough variation to ensure that many survive and continue to evolve.
Over the course of the 10,000 years that people have been evolving from being hunter / gatherers to farmers, thousands of varieties of plants have been domesticated. This means that people have saved the seed from plants that produced well or tasted best or could withstand drought or pests etc in the wild or the field and sown that seed the following year. Each farmer saved his own seed but also swapped with neighbours and travellers; consciously or unconsciously keeping the gene pool diverse and evolving.
Crop diversity can be used as a resource to mediate potential stresses of the surrounding environment. A crop population with a diverse genetic makeup may have a lower risk of being entirely lost to any particular stress, such as temperature extremes, droughts, floods, pests, and other environmental variables. Crops with different planting times and times to maturity give the farmer the option to plant and harvest crops at multiple points in the season to guard against total crop loss to environmental threats.
Presently, humans are taking the very dangerous route of attempting to control evolution, by controlling seed availability and literally stopping the evolution of major food crops. This is being done in various ways. I don't want to discuss here who is doing this and why but merely to explain how we home gardeners and consumers can help keep evolution alive. The seeds, seedlings and vegetables you buy in supermarkets are becoming so removed from being whole organisms that they are verging on artificial versions of their ancestors. Selection is made for shelf life and appearance and once this is achieved, seed production becomes fixed and no more evolution is allowed to occur. Every year the same seed with the same name produces the same crop.... as long as conditions remain the same!
Research is beginning to show how devoid of nutrition mass-produced vegetables have become and how weak the plants are when even slight changes occur in their growing conditions. Should a particular chemical ingredient become unavailable,or average temperatures change, whole crops would fail. For example, so much of agricultural fertilisers are products of oil. What happens as oil becomes more expensive and less available? Already in Australia farmers are having difficulty accessing artificial fertilisers and are struggling to find other varieties to sow with a reduced chemical input requirement because the gene pools of some grains have been allowed to dwindle and in some cases we are almost down in numbers equal to polar bears, with the fittest already extinct. There used to be thousands of varieties of rice and wheat but now agri-business has destroyed the individual seed saver's diversity and in its place has sown a limited range of varieties world wide which are always the same and never evolve.
The answer is to ask questions, lots of questions....Buy produce from small, local growers who can name the variety of broccoli or beans or carrots that they have for sale this week. Ask about their growing methods and their seed acquisition. Ask if they save their own seed. Ask them how they extend their seasons. A smile will break out on the face of any grower passionate about his crops and you will learn stories of families and immigration and seedsaving and world wars and manures and compost.
Grow your own vegetables and get your seed from local seedsavers exchanges or small, independent seed companies, like those in the side bar of this blog. Try growing something different and save the seeds yourself. Be part of the solution not the problem.
Read websites such as Bioversity International and see what is being done to maintain food biodiversity in little nooks and crannies of our world. The paragraph of this piece which is in italics, and its accompanying photo, are from the section called Agricultural Ecosystems and is worth reading in more depth.
And Maggie, there'll be a test later!