Abstract
Abstract During the voyage of the H.M.S. Beagle, Charles Darwin quickly realized that geographic isolation led to significant changes in the adaptation of local flora and fauna (Darwin 1859). Genetic isolation is one of the well-known mechanisms by which adaptation (allopatric speciation) can occur (Palumbi, Annu Rev Ecol Syst 25:547–72, 1994; Ricklefs, J Avian Biol 33:207–11, 2002; Burns et al., Evolution 56:1240–52, 2002; Hendry et al., Science 290:516–8, 2009). Evolutionary changes can also occur when landmasses converge or are “bridged.” An important and relatively recent (Pliocene Epoch) example known as the “Great American Biotic Interchange” allowed for the migration of previously isolated species into new ecological niches between North and South America (Webb 1985, Ann Mo Bot Gard 93:245–57, 2006; Kirby and MacFadden, Palaeogeogr Palaeoclimatol Palaeoecol 228:193–202, 2005). Geographic isolation (vicariance) or geographic merging (geodispersal) can occur for a variety of reasons (sea level rise, splitting of continents, mountain building). In addition, the growth of a large supercontinent (or breakup) may change the climatic zonation on the globe and form a different type of barrier for species migration. This short review paper focuses on changing paleogeography throughout the Phanerozoic and the close ties between paleogeography and the evolutionary history of life on Earth.
Highlights
Because ocean floor magnetic anomalies can only be reliably traced back to Mesozoic time, reconstructions of Paleozoic and earlier continental reconstructions rely almost exclusively on faunal and geological comparisons (Meert and Lieberman 2004; Cocks and Torsvik 2002)
Reconstructing past maps of the Earth requires the ability to determine both the age of the rocks and the paleoposition of the rocks at the time they formed. Modern geochronological methods such as uranium–lead (U–Pb) and argon–argon (Ar–Ar) provide precise constraints on the ages of igneous, metamorphic, and sedimentary sequences. When these geochronologic data are tied to the fossil record, it is possible to determine the rates of evolutionary change as well as pinpoint time intervals of radiation and extinction (Bowring and Erwin 1998)
The time required for the average position of the geomagnetic field to approximate the position of the spin axis is thought to be on the order of 7,000–10,000 years
Summary
Because ocean floor magnetic anomalies can only be reliably traced back to Mesozoic time, reconstructions of Paleozoic and earlier continental reconstructions rely almost exclusively on faunal and geological comparisons (Meert and Lieberman 2004; Cocks and Torsvik 2002). Reconstruction of the continent, assuming a normal magnetic field existed during formation of the rock. Reconstruction of the continent, assuming a reverse magnetic field existed during the formation of the rock.
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