You begin with a lot of ideas bouncing around in your head. Experience teaches you about reality.
The reality that insecticides and herbicides, properly used, were wonderful revolutions in horticulture.
The reality of how there really isn't any money to be made.
The realities of how fragile life really can be.
When we first got goats I realized fairly quickly that I needed to supplement with selenium. We'd raised rabbits with a combination of hay and store bought feed. We'd raised chickens on a mix of grain and household scraps.
Feeding store bought feeds and human scraps, the selenium wasn't a problem. Feeding goats on pasture, I learned that even my lush hillside was not self-sufficient, even if I kept the number of herbivore's low. We needed to import something and that something was selenium.
Thanks to big data, researchers can now take a long look at the prevalence of minerals in the environment over the eons and one look at that data suggests that global selenium deficiency may have contributed to three of the planet's mass extinctions.
But in periods where landmasses are drifting apart – such as 200 million years ago, when the vast supercontinent Pangaea was breaking up – selenium levels can collapse.Towards the end of the Triassic period, 205 million years ago, selenium levels were around 60 parts per million in ocean sediments. Just three million years later, that figure plummeted to less than two parts per million. Large found similar patterns at the end of the two other unexplained mass extinctions – the Ordovician (more than 440 million years ago) and the Devonian (more than 355 million years ago).