This dissertation employs the theory of self-organizing criticality (SOC) into the study of Chinese cities. SOC was proposed at the end of the 1980s to explain system complexity by combining both self-organizing and critical behaviors. SOC has been broadly used in explaining phenomena in physical and social sciences. However, few attempts have been made to connect urban studies with SOC because of the extreme complexity of urban phenomena. This study develops a generalized SOC to study Chinese cities at both the inter-urban and the intra-urban levels. At the inter-urban level, this study finds that the rank size distribution of Chinese cities has followed Zipf's law since 1984. In addition, the rank size dynamics of Chinese cities experienced a spatiotemporal shift. Before 1996, city rank increases in a few small- and middle-sized cities because of favorable economic policies offered by the central government. After 1996, a majority of the Chinese cities began to be involved in this rank size shuffling. Cities with increasing ranks present clustered distribution, mainly along the south and east coastal areas. Part of the reason is that the market economy mechanism has transcended policy factors in determining the city competitiveness. At the intra-urban level, the study shows that Shenzhen's urban physical development is currently facing physical environmental thresholds, shifting the development strategies spatiotemporally from fringe and isolated growth to fringe and infill growth. The resulted urban patches show power law relationship both in the area-perimeter distributions and the magnitude-frequency distributions. In summary, this research proves the applicability of the generalized SOC in urban studies. At both the inter-urban and the intra-urban levels, the Chinese cities present the characteristics of SOC. Given a stable condition of power law, shifts occur in the inside dynamics of China's urban system and Shenzhen city. This study is one of the few empirical urban studies based on SOC. The study contributes to the literature on SOC theory and provides theoretical breakthroughs in studying Chinese cities. Finally, this study has potential implications on urban policies and urban development strategies.

This dissertation comprises three articles that propose explanations for the eventual extinction of Neanderthals in Europe after a period of several thousand years of coexistence with anatomically modern humans (AMH). I propose that bioenergetic differences between Neanderthals and AMH favored the persistence of AMH. This difference in energetic efficiency was augmented by any behavior that was advantageous to AMH. Consequently, such behaviors directly impacted the rate of Neanderthal extinction. The first article proposes a mathematical model that reconstructs Neanderthal and AMH energetic budgets to predict how using fire for cooking might have affected the success of each species. I first use the model to establish that energetic differences alone result in Neanderthal extinction when Neanderthals and AMH occupy the same landscape. I then establish that cooking meat increases its caloric value, and incorporate that parameter into the model. The outcome indicates that differential fire use by Neanderthals and AMH significantly affects the rate of Neanderthal extinction. The second article analyzes the evidence for marrow and bone grease extraction from reindeer carcasses by Neanderthals and AMH during cold climate phases. I analyze two assemblages produced by Neanderthals and three produced by AMH to determine how each group exploited these crucial nutritional resources. Results indicate that marrow processing intensity correlates with site function rather than with human species while bone grease may have been more intensively processed by AMH. In the third article, I integrate these studies within a new theoretical framework combining self-organizing criticality (SOC) and resilience thinking (RT). I explore Neanderthal extinction across multiple scales. SOC explores how interactions at the scale of the individual can combine to cause events such as an extinction. RT provides a systems-level framework for understanding how patterns of change among Neanderthals, AMH, prey populations, and the landscapes they inhabit may lead to instability and collapse. I identify the arrival of AMH into a landscape occupied by Neanderthals as a threshold point that set the process of Neanderthal demise in motion. I then use SOC and RT together to explain Neanderthal extinction as a slow and patchy process, rather than a sudden extinction.