Humans created agriculture by selecting for desired properties of plants and animals. The result of human selection is much like natural selection but greatly speeded up and directed towards humanly preferred results.

Natural selection moves evolution forward by allowing genetically stabilized improvements to persist, while inferior results deteriorate away. The process of each improvement excelling over previous states is very slow, because many generations are needed to increase the number of improved individuals.

When humans pick the type that they prefer, they produce many generations with no inferior types involved. So each human selection of types moves the result forward each time, which would be every year, when plant seeds are grown.

In doing that, humans create some extreme evolution for domesticated agriculture, which often includes multiple copies of genomes per cell.

A very unusual example which tells oceans about the process is tartaric acid in grapes. Scientists cannot find a biological function for the tartaric acid. Evolution physiology tells the story.

One of the most unexpected features of tartaric acid in grapes is the large quantity. The necessity shows why. As humans selected grapes for best results, the types that produced tartaric acid were selected for, of course knowing nothing of the biochemistry, as the process occurred over thousands of years.

What tartaric acid does in grapes is prevent the bacteria from overtaking the fermentation of wine. But the accumulated acid was not the best result. So selection resulted in a precipitation of the tartaric acid during the wine making process.

No other acid would precipitate during wine-making but tartaric acid. As it precipitates, it coats the surfaces with tartaric acid crystals. Those crystals are edible but not desired; and they can be left behind on surfaces. To do that, the wine must age in one container and then be transferred to another.

Wine making has a lot of subtle art to it. Going through just the right process causes the tartaric acid to form and inhibit bacterial growth and then precipitate out to improve wine quality. No biochemistry needed to be known, as long as the proper procedures were followed.

And of course, the grapes that work best for doing that are the ones that produce a lot of tartaric acid. So human selection created grapes that produce a lot of tartaric acid with no known biological reason besides human selection for preferred wine-making results.