What does it really mean to domesticate an animal or a plant?

To domesticate a species means to enter a long-term partnership with it, one that lasts across many generations. Humans take over the control and care of another species, feeding it, protecting it and steering its breeding, to get a steady supply of something: meat, milk, wool, labour. The deal runs both ways, which is why scientists call it a mutualistic relationship. Sheep get shelter and pasture, and people get a reliable flock.

That is different from taming. A tamed lion is one individual that has learned to put up with a keeper. A domesticated species has changed, in its genes, over generations. The word itself comes from the Latin domesticus, meaning 'belonging to the house'. The changes make animals and plants easier to handle, and they also make them worse at surviving without us. In animals, domestication mostly shifts genes for behaviour and makes them less aggressive. In plants, it shifts the shape of the plant, such as larger seeds and seedheads that no longer burst open.

The process was never a master plan. It was gradual, spread over wide areas, and based on trial and error. For animals that drifted into human company or were hunted for food, people did not set out to create a domestic species, or at least did not foresee the result. The dog came first, at least 15,000 years ago. Goats, sheep and cows came around 11,000 years ago, and the first crops, such as wheat and barley, arrived roughly 13,000 to 11,000 years ago in the Middle East.

Humans also have company. Ambrosia beetles, leafcutter ants and fungus-growing termites have each domesticated fungi that they eat, so the idea is bigger than farming.