Understanding Climate's Influence on Human Evolution (2010) / Chapter Skim
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1 Introduction
1 Introduction
Pages 9-15
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From page 9... ...
This fossil record contains a history of critical evolutionary events that have ultimately shaped and defined what it means to be human, including the origins of bipedalism; the emergence of our genus Homo; the first use of stone tools; increases in brain size; and the emergence of Homo sapiens, more advanced tools, and culture. Some of these events appear to have coincided with major changes in African climate, raising the intriguing possibility that key junctures in human evolution and behavioral development may have been climatically mediated.
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From page 10... ...
These challenges affected how early humans secured food, found shelter, escaped predators, and developed social interactions that favored survival. The capacity to make tools, share hunted-and-gathered food, control the use of fire, build shelters, and create complex societies based on symbolic communication set the stage for new ways in which humans interacted with their surroundings.
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From page 11... ...
Three examples -- from progressively older parts of the evolutionary and earth records -- illustrate the way in which hominins may have interacted with the earth system and illustrate some of the enduring scientific questions that remain to be explored: The Mayan "Collapse" Between A.D. 750 and 1150, the Classic Mayan civilization of southern Mexico and Central America underwent a dramatic transformation involving complex changes in Mayan society and an apparent collapse of population size by 70 percent or more (Turner, 1990; Rice et al., 2004)
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From page 12... ...
There is a common thread in these three examples of interactions between our human ancestors and the earth system -- in each case, scientists face major limitations in resolving fascinating questions about our origins and history. A transformation in our understanding of the human story requires an improved understanding of the timing of critical evolutionary and climatic events, an improved sampling of the fossil and archaeological evidence for critical intervals in human prehistory, and -- perhaps most importantly -- a dramatic change in the way in which earth scientists, climate scientists, and anthropologists work together to interpret this story.
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From page 13... ...
, initial environmental conditions, and findings from the fossil record. An important consideration in any discussion of causality is the possibility that hominin evolution was largely unaffected by climate change -- the evolution–environment "null hypothesis." Ecological factors such as predation, competition, and disease among organisms operate in all environments, and these interactions have an important influence on their evolutionary history.
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From page 14... ...
These mutations become widespread because natural selection relies on the concept that environment plays the vital role in the difference between evolutionary success and extinction. An improved understanding of environmental change -- that is, the earth system context as a dynamic force in evolutionary success and extinction -- will substantially advance the scientific understanding of life on our planet, including human evolution.
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From page 15... ...
Chapter 3 contains a description of two overarching research themes, encompassing a range of individual research initiatives, which have the greatest potential to provide major advances in the understanding of potential interactions between the earth system and hominin evolution, and Chapter 4 describes the implementation strategies that will be needed to address these themes and initiatives. Recognizing deficiencies in the understanding of evolutionary principles and processes in the wider nonscientific community, Chapter 4 also contains the committee's response to the specific charge to suggest dissemination strategies.
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