Every time a species becomes extinct it is like pulling a brick out of the foundation. This constitutes a grave threat to our world food security. In 1990 Robert and Christine Prescott-Allen, looking world wide, suggest that human diets rely on 103 species. Genetically speaking this is a minuscule number of what is available for our use. The Diversity of Life states preservation of the natural system is the only answer to preservation of the world's biodiversity.
Seed banks are vulnerable to political upheaval, fires, and earth quakes.
As generations came and went and seeds were selected by the farmer and handed down to his sons, each farmer eventually held seeds unique to his own farm. Traditional crop varieties developed in this way are known as landraces. Over the centuries they have accumulated by the tens of thousands. The agricultural gene pool is shrinking. Large seed companies have the best opportunity to exploit plant genetic engineering.