STEALTH EDUCATION
tion, oceanic upwelling relationships to nutrient availability for commercial fishing, whale migration patterns, El Nino/La Nina impacts on weather and climate patterns, and, by extension, the importance of glaciation to water resource availability in the Western United States, both at present and in the past.
Expansion of discussion can be used in conjunction with figure 4 to introduce the concepts of coastal environments as factors in the development of early civi- lizations in Central and South America. These coastal environments provided effective oases of water and abundant food from marine and terrestrial sourc- es. This in turn provided excess labor which allowed the labor specialization necessary for development of the civi- lizations (Soconusco, Mixtec, Olmec, Mayan, Incan etc.) of the coastal regions of Central and South America, which then expanded inland along streams and through gaps in the volcanic chains which characterize the western coasts of the central and southern Americas.
Figure 3 – Potential Migration Pathways from Asia and Europe to the Americas, Modified from Stanford and Bradley, Across the Atlantic Ice, 2013.
The influences of rivers and streams as transportation pathways from coastal regions to continental interiors pro- vide entrees to discussions of mountain building, stream runoff and river devel- opment, physiographic and adiabatic controls on coastal climate variability, marine current and upwelling effects on
marine life, weather patterns, monsoonal controls associated with the Intertropical Convergence Zone, as well as other elements directly associated with the tectonic setting of the Americas.
Figure 5 introduces the concept of land bridges as low sea level pathways for migration into what are now apparently isolated Caribbean islands. This figure illustrates the potential movement of humans and other terrestrial animals into the Caribbean islands with subsequent isolation into the modern archipelago. This discussion can be expanded to include other areas as well, e.g. the Mediterranean Islands, the South Pacific Archipelagoes, Japan, Taiwan, the Aleutians, Madagascar, Great Britain, etc.
Lower sea level associated with glacial maxima allowed island-hopping by reducing the open water separation between land masses. In some cases, direct connection with the mainland was present (e.g. Trinidad, Great Britain, and the Maritime Provinces of Canada). Now separated modern islands were often part of a single landmass at the time of human entry into the area as illustrated by Figure 6 showing the Anguilla Bank, once a land mass including the island of St. Martin, Anguilla and St. Bartholemy. Glacial melting over the past 10,000 years resulted in a 300+ foot sea level rise producing the present island chain configuration we know today as the Caribbean Islands.
These types of illustrations are very useful in allowing the introduction of glacial cycles, climate change, sea level rise
Figure 4 – Holocene Migration Pathways in South America Rothhammer and Dillahay, 2001.
www.aipg.org Continued on p.46
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