Monday, June 23, 2014

Agriculture and food plants (extra)

When people started to plant stored seed stock deliberately, they also began protecting their plant. This changed the evolutionary pressure that these food plants experienced, as they no longer had to survive in a natural environment. Instead, people created a new environment for them, and selected for other characteristics than what nature previously had. Seeds recovered at archaeological sites clearly show that early farmers selected for larger seeds and thinner coats. Thick, impermeable seed coats are often essential for seeds to survive in a natural environment, because the seeds of many wild plants remain dormant for months until winter is over and rain sets in. But under human management thick seed coats are unnecessary, as farmers take over responsibility for storing seeds away from moisture and predators. In fact, seeds with thinner coats were preferred as they are easier to eat or process, and they allow seedlings to sprout more quickly when sown.

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