Domestication is a defining feature of recent human evolution. In animals first trait selected by humans was behavior. In plants harvestability through selection of non-shattering seeds was the first trait of domestication. Plant domestication paved the way to agriculture which enabled highly specialized sedentary human societies. Domesticated plants differ from their wild ancestors in distinct ways that can be categorized under a term called as the domestication syndrome. Domestication syndrome includes reduced shattering of seeds (seeds don’t separate from the mother plant), absence of dormancy (fast and synchronous germination), insensitivity to daytime length, reduced defensive chemicals, altered biomass allocation.
In his book Michael Pollan focuses on four plants that has been under artificial selection by humans for quite different functions such as sweetness (apple), beauty (tulip), intoxication (cannabis) and high calorie content (potato).
Apple is one of the first trees that has been cultivated and maintained through grafting by people. Because of the high genetic variation and exceptionally high rate of genetic recombination apple trees can be very different from one generation to the other if planted from seed. Ancestral humans propagated best apples by grafting cuttings. Apple genome sequencing was completed in 2010 and results were published in Nature Genetics and apple breeding will take off like never before.
Apple isn’t the first domesticated plant in search of sweetness. Sugar is a very effective driver in behavior of animals. Glucose is the sole fuel of the brain. Plants have lured animals using sweet nectar as a currency in many adaptive ways. Heliconia plant of the New World tropics attracts hummingbirds for pollination of its flowers. Many plant families including the Passion flower (Passiflora spp.) uses extrafloral nectaries to attract ants as protectors. Here by sweetness, apple is using Humans as vectors to increases its fitness. At the same time it evolves under selective pressure exerted by farmers seeking for the sweetest individuals. The history of humans with sugar goes back to more than 10 thousand years ago to the island of New Guinea where sugarcane was first domesticated. Together with humans sugarcane also spread and reached Asian mainland. Indian Ocean is the first place where a truly global economy emerged in human history thanks to Arab sailor merchants. These sailors brought sugar everywhere in the old world and until the discovery of the new world Ottomans controlled its trade. Sugarcane completed it’s world journey a few centuries ago when it was brought to the Americas.
Just like sugarcane many plants became domesticated and traveled the world with humans. Today even the most remote “uncontacted human tribes” in the Brazilian Amazon cultivate banana for instance which is a plant that was domesticated strictly in the old world (see the banana plantations visible in the following aerial footage):
Uncontacted Amazon Tribe: First ever aerial footage from Survival International on Vimeo.
Plants unfortunately get less attention from filmmakers. This is most probably due to a narration problem. For example, when we see animals in a video we more or less can guess what we are seeing. Natural history of plants require some powerful story telling simply because their life cycles and interactions with the community around them are not very obvious.
Domesticate.
7 Comments