Genetic Chaos

Monday, March 29, 2004

Latitudinal patterns and environmental determinants of recent human cultural diversity: do humans follow biogeographical rules?

Biogeographers have noted many strong patterns in the diversity and distribution of animal and plant taxa. Human cultural diversity also exhibits strong geographical patterns. Here we analyse the global distribution of 3814 human cultures in relation to latitude and climatic parameters. The density and diversity of human cultures declines with latitude and increases with temperature and rainfall. Human cultures in tropical, wetter or warmer areas have smaller ranges and are more densely packed and differentiated. These relationships can be documented statistically in ways that parallel species diversity among other organisms. The global nature of these patterns implies ecological equilibrium independent of evolutionary history in different continents, and has implications for the interpretation of human genetic diversity, as well as for the understanding of processes of human cultural diversification and their relationship to evolutionary and ecological mechanisms.

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