mardi 28 juin 2016
Termites and not humans invented farming 25 millions years ago
The research team, led by Eric Roberts of James Cook University and that also included researchers from Ohio, have discovered the oldest known examples of “fungus gardens” in 25 million-year-old fossil termite nests in East Africa. The fossilised termite gardens that exposed cliff sides in the Rukwa Rift Basin of southwestern Tanzania uncovered are the oldest physical evidence of farming on Earth.
According to the study, published in journal PLOS ONE, certain termite species cultivate fungi in “gardens” in subterranean chambers or nests that help them convert plant material into more easily digestible termite food source. DNA from modern termites revealed that termite fungus farming started around 25 to 30 million years ago. Tanzania’s fossil evidence confirmed the date and also allowed the researchers to specifically characterise evolution and timing of the symbiotic relationship between termites and fungi.
“The origin of this behaviour likely had a profound effect on how nutrients were concentrated across the landscape, influencing the evolution of Africa's biota,” study co-author Nancy Stevens of Ohio University said in a statement.
Program director in the National Science Foundation (NSF) Directorate for Geosciences, Paul Filmer, said that as termites digest 90 percent of the wood in the dry environment, a better understanding of the symbiotic relationship development will help in gaining “knowledge of the history of carbon cycling in this region.”
Wageningen University in the Netherlands researcher Duur Aanen compared the termite farming process to humans and domesticated livestock and crops that happened tens of millions of years later. The changeover to fungus agriculture improved the variety of possible habitats for both the fungus-growing termites and domesticated fungi.
It is believed that termite agriculture flourished in the cradle of the African rainforest. Fungiculture allowed termites to spread out to less hospitable areas and eventually spread out to Asia.
“This study emphasises the need for integrating perspectives from the fossil record with modern approaches in comparative biology -- it's a holistic approach to evolutionary biology and increases our understanding of environmental change in 'deep time,” said scientist Patrick O'Connor of Ohio University.
Source : http://www.ibtimes.com.au/termites-not-humans-invented-farming-25-million-years-ago-1519895