Today we will go over Chapter 7; we are reading one chapter a week.
I encourage this to be slow blogging - the very opposite of "breaking". I will leave this on my hot list for a week, so comment any time during the week.
When we get near the end of GGS, I'll start a poll for the next book; I am strongly leaning towards the book Ideas: A history of thought from fire to Freud.
Ground rules: I expect vigorous discussion. But I expect civil discussion. A sign I saw in a restaurant said
Be nice or leave
If you want to have a flame war, go elsewhere, please.
Chapter 7 discusses how plants got domesticated.
Wild plants are much less useful to humans than their cultivated versions. Some (like various berries) are just smaller. Others (like almonds) are usually poisonous (a dozen wild almonds can contain enough cyanide to kill you).
How did these plants get domesticated, long before people knew about genes and such?
The whole chapter is about this, but here are some ways:
Many fruits exist to spread seeds. People naturally chose to eat the larger fruits, and then they spread those seeds through defecation. A lot of plants started growing in latrines, and the ones in human latrines tended to be the seeds that produced larger and sweeter fruit. With almonds, there is a single gene that produces both the bitter flavor of wild almonds, and the cyanide. Humans ate the nonbitter, nonpoisonous almonds, and spread those seeds - first, again, in their latrines; later, more consciously, by planting seeds of the right trees. In similar ways, with different plants, we selected plants for oiliness, fleshiness, and fiber length.
Another set of ways we modified plants involves their means of propagation. Wild peas, for example, have pods that explode, spreading the seeds (the peas themselves) on the ground. But people would only eat the peas in pods that did not explode, thus selecting for that type of pea. Other plants (like wheat) enclose their seeds in thick coats, so that some will survive a drought. But once humans started planting them, the seeds that reproduced fastest were the ones with less thick coats.
There's a lot more detail in the chapter - it's pretty interesting stuff.
Here's a question for discussion:
Given the fact that we've been modifying plants for tens of thousands of years, just what is 'natural' and just what is 'genetically modified'?
Have fun in the comments!