27 ms·
What 9,000 years of breeding has done to corn, peaches, and other crops
- dalke 11y agoThe distribution maps are odd. My best interpretation is that the "natural" map shows the countries where a species can be found while "artificial" maps show those countries where a species is economically significant. I say this because the modern maize map does not include Sweden, but maize is grown in Sweden. (See http://www.alamy.com/stock-photo-maize-zea-mays-crop-flowering-in-field-narke-svealand-sweden-august-61846170.html http://www.alamy.com/stock-photo-maize-zea-mays-crop-floweri... for a picture, see http://småbruk.se/gronsaksodling/majsodling/ http://småbruk.se/gronsaksodling/majsodling/ for a description (in Swedish) of a hobby gardener growing sweet corn in Sweden.) Thus, the maps on the right-hand side should likely show a more extensive range for the domesticated variants. You might believe that makes the argument even stronger. However, consider tigers. While neither domesticated nor native to many countries, tigers exist in and are reproduced in many countries. (http://zooborns.typepad.com/zooborns/tiger/ http://zooborns.typepad.com/zooborns/tiger/ gives recent births in the US, UK, Germany, Denmark, and the Czech Republic.) A species distribution map using the similarly broad category would show that tigers are now wide-spread. Thus, I think it's reasonable to conclude those maps were made more for their immediate propaganda effect than as something where it's possible to draw useful inferences from the direct comparison of the two maps. (There are of course other problems with the map. Removal of milkweed in order to raise maize and other crops has lead to a steep decline in the monarch butterfly population. However, these maps cannot be used to address these broader.)