[im] The broiler chicken as a signal of a human reconfigured biosphere

[János Sugár]

https://royalsocietypublishing.org/doi/10.1098/rsos.180325

Carys E. Bennett , Richard Thomas , Mark Williams , Jan Zalasiewicz , 
Matt Edgeworth , Holly Miller , Ben Coles , Alison Foster , Emily J. 
Burton  and Upenyu Marume
Published:12 December 2018

https://doi.org/10.1098/rsos.180325

Abstract

Changing patterns of human resource use and food consumption have 
profoundly impacted the Earth's biosphere. Until now, no individual 
taxa have been suggested as distinct and characteristic new 
morphospecies representing this change. Here we show that the 
domestic broiler chicken is one such potential marker. Human-directed 
changes in breeding, diet and farming practices demonstrate at least 
a doubling in body size from the late medieval period to the present 
in domesticated chickens, and an up to fivefold increase in body mass 
since the mid-twentieth century. Moreover, the skeletal morphology, 
pathology, bone geochemistry and genetics of modern broilers are 
demonstrably different to those of their ancestors. Physical and 
numerical changes to chickens in the second half of the twentieth 
century, i.e. during the putative Anthropocene Epoch, have been the 
most dramatic, with large increases in individual bird growth rate 
and population sizes. Broiler chickens, now unable to survive without 
human intervention, have a combined mass exceeding that of all other 
birds on Earth; this novel morphotype symbolizes the unprecedented 
human reconfiguration of the Earth's biosphere.