Evolution News Plants

Weeds evolve at high speed? And it’s our fault, due to farming

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From New Scientist:

The remains, which date to a time just 2000 years after farmers sowed their first seeds, include durum wheat, figs, chickpeas (garbanzos) and herbs. Alongside these important crops there is evidence of at least 35 weed species – suggesting that it didn’t take long for opportunistic herbaceous plants to adapt to our agricultural revolution.

What’s more, five of those species – including darnel and Egyptian hartwort – appear to have been obligatory weeds, meaning they can usually only grow in cultivated fields.

So they evolved by losing information? Like most evolution we have actually observed?

We are told that the crop weed darnel somehow evolved to look like wheat.

But do we know that darnel didn’t just always happen to look like that (it is a rye grass)? Which makes it difficult to remove, hence allowing it to survive, relative to other weeds. In fact, that was the precise point of an ancient parable:

Jesus told them another parable: “The kingdom of heaven is like a man who sowed good seed in his field. But while everyone was sleeping, his enemy came and sowed weeds among the wheat, and went away. When the wheat sprouted and formed heads, then the weeds also appeared.

“The owner’s servants came to him and said, ‘Sir, didn’t you sow good seed in your field? Where then did the weeds come from?’

“?‘An enemy did this,’ he replied.

“The servants asked him, ‘Do you want us to go and pull them up?’

“?‘No,’ he answered, ‘because while you are pulling the weeds, you may uproot the wheat with them. Let both grow together until the harvest. At that time I will tell the harvesters: First collect the weeds and tie them in bundles to be burned; then gather the wheat and bring it into my barn.’?”

A researcher opines:

“I’ll bet that weeds were the big problem in early monocultures – and picking weeds may have consumed a lot of time for those early farmers,” says McDonald.

The parable suggests that they didn’t actually do much of that; they just harvested the good stuff and burned the rest. Their agriculture was much less productive than today’s, probably, but we are here because they persisted. Follow UD News at Twitter!

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