Early Odds

Kevin Lewis

June 08, 2024

The importance of continents, oceans and plate tectonics for the evolution of complex life: Implications for finding extraterrestrial civilizations
Robert Stern & Taras Gerya
Scientific Reports, April 2024

Within the uncertainties of involved astronomical and biological parameters, the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing the importance of planetary tectonic style for biological evolution. We summarize growing evidence that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated emergence and evolution of complex species. We further suggest that both continents and oceans are required for ACCs because early evolution of simple life must happen in water but late evolution of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox (1) by adding two additional terms to the Drake Equation: f-oc (the fraction of habitable exoplanets with significant continents and oceans) and f-pt (the fraction of habitable exoplanets with significant continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by demonstrating that the product of f-oc and f-pt is very small (< 0.00003–0.002). We propose that the lack of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on exoplanets with primitive life.

War and the origins of Chinese civilization
Zhiwu Chen, Peter Turchin & Wanda Wang
University of Connecticut Working Paper, April 2023

Why did complex societies, characterized by densely-populated walled cities, first arise in northern China, jump-starting early Chinese civilization? We explore this question in three steps. First, the North, especially the alluvial plains along the Yellow and the Yangtze Rivers, had generally flatter terrains than the South. Second, by dividing China’s landmass into 100 km × 100 km grid-cells and using our archaeological database, we demonstrate that cells with flatter terrains faced higher war threats in prehistoric and early historic times, where war threats are respectively proxied by each cell’s number of excavated military grave goods for the Neolithic period (8000−1700 BCE) and by its number of recorded conflicts for the Eastern Zhou (770−221 BCE, the earliest period for which war data are available). Third, we establish that during both the Neolithic and the Eastern Zhou, higher war threats led to the construction of more settlements with defensive walls and moats, resulting in more walled cities (i.e., early cradles of civilization). Thus, warfare was a key driver of the evolution of complex societies. This finding is robust after controlling for irrigation potential, agricultural productivity, and threats from the steppe, as well as under alternative specifications.

From Roman Table to Anglo-Saxon Grave: An Archaeological Biography of the Scremby Cup
Hugh Willmott et al.
European Journal of Archaeology, forthcoming

The presence of Roman material in early Anglo-Saxon graves in England is well documented, and recent excavations at Scremby in Lincolnshire have revealed a complete copper-alloy enamelled drinking cup in a sixth-century AD female burial. Not only is such a Roman vessel a very rare find, but also its inclusion in an early medieval grave makes it a unique example of the reuse of an antique object in a funerary context. This article presents a typological and metallurgical analysis of the cup and selected comparative examples from England and France are discussed. The context of deposition and the role the cup played as a burial container for animal fat are examined, as are the mechanisms that lay behind the cup's continued life several centuries after its manufacture.

The time between Palaeolithic hearths
Ángela Herrejón-Lagunilla et al.
Nature, forthcoming

Resolving the timescale of human activity in the Palaeolithic Age is one of the most challenging problems in prehistoric archaeology. The duration and frequency of hunter-gatherer camps reflect key aspects of social life and human–environment interactions. However, the time dimension of Palaeolithic contexts is generally inaccurately reconstructed because of the limitations of dating techniques, the impact of disturbing agents on sedimentary deposits and the palimpsest effect. Here we report high-resolution time differences between six Middle Palaeolithic hearths from El Salt Unit X (Spain) obtained through archaeomagnetic and archaeostratigraphic analyses. The set of hearths covers at least around 200–240 years with 99% probability, having decade- and century-long intervals between the different hearths. Our results provide a quantitative estimate of the time framework for the human occupation events included in the studied sequence. This is a step forward in Palaeolithic archaeology, a discipline in which human behaviour is usually approached from a temporal scale typical of geological processes, whereas significant change may happen at the smaller scales of human generations. Here we reach a timescale close to a human lifespan.

Early animal management in northern Europe: Multi-proxy evidence from Swifterbant, the Netherlands
Nathalie Brusgaard et al.
Antiquity, June 2024, Pages 654-671

The nature and timing of the transition to farming north of the Linearbandkeramik zone in Europe is the subject of much debate, but our understanding of this fundamental shift in lifeways is hampered by the low resolution of available data. This article presents new multi-proxy evidence from Swifterbant (4240–4050 BC), in the Dutch wetlands, for morphologically domestic cattle with two different dietary regimes. The authors argue that the results indicate early animal management, alongside arable farming and the continuance of foraging practices, prompting the reconsideration away from broad statements about the Neolithic north of the Linearbandkeramik zone towards more local trajectories.

Early Holocene exploitation of taro and yam among southern East Asian hunter-gatherers
Weiwei Wang et al.
Antiquity, June 2024, Pages 597-615

Increases in population size are associated with the adoption of Neolithic agricultural practices in many areas of the world, but rapid population growth within the Dingsishan cultural group of southern China pre-dated the arrival of rice and millet farming in this area. In this article, the authors identify starch grains from taros (Colocasia) and yams (Dioscorea) in dental calculus and on food-processing tools from the Dingsishan sites of Huiyaotian and Liyupo (c. 9030–6741 BP). They conclude that the harvesting and processing of these dietary staples supported an Early Holocene population increase in southern East Asia, before the spread of rice and millet farming.


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