Every second, people around the world drink more than 26,000 cups of coffee. some of them may care only about the taste, and some of them may use it as a way to wake them up in the morning.
To humans, coffee is a valuable beverage crop due to its characteristic flavor, aroma, and most importantly the stimulating effects of caffeine. While we appreciate the diverse fragrances of a cup of coffee and the stimulation of the world’s most popular drug, we know little about its origin and forget coffee is the result of hundreds of thousands of years of plant evolution.
As a crop, high land Coffee Arabica and low land Robusta are the products of the only two coffee species cultivated now in over 50 tropical countries. However, according to IRD researchers, “a total of nearly 120 wild Coffee species exist starting from their origin in Lower Guinea, colonized the whole of Equatorial Africa and the Madagascar region in 400,000 years ago.” According to this French research organization, The true origin of coffee plants is neither the legend of the dancing goats in Ethiopia, described since the 8th Century, nor the theory of coffee species originating on the Horn of Africa before the Gondwana super-continent broke up more than 100 million years. (Courcoux)
Over the past 400,000 years, cycles of glaciation happened every 100,000 year that result in a high variability in climate and intense phases of cooling. However, during this period, the flora has survived and spread in refuge zones/biodiversity hot spots (regions suitable for forests at altitude or near oceans), such as Lower Guinea. The coffee species then diversified.
https://en.ird.fr/the-media-centre/scientific-newssheets/347-a-new-history-of-coffee
http://www.lahistoriaconmapas.com/atlas/africa+map/guinea-africa-map.htm