Cyclic Hominid Evolution in A Moroccan-Algerian Coastal Refuge: The Last Million Years

  • Robert Glenn Johnson University of Minnesota
  • Andre Berger Université catholique de Louvain
Keywords: Hominid evolution, Ice age climate change, Orbital insolation, African monsoons, Hominid refugia, Human origins


To explain the abundance of species of genus Homo in the fossil record of Africa south of the Sahara, the small Moroccan-Algerian coastal zone that was isolated by the barren Sahara is proposed to have been a refuge in which cyclic evolution occurred. A dry climate in combination with a small population enabled natural selection to generate new sub species or species during each climate cycle. As generalized from the last two major glaciations, in each cycle three coastal zone climates of differing aridity occurred, depending on the latitudinal zonality of high latitude Gulf Stream flow. When initially isolated with minimal zonality (strong northward North Atlantic Drift of Gulf Stream water), the coastal climate was like today’s, with warm summers and mild winter rains. Subsequently during intervals of ice sheet growth with intermediate zonality (weaker Drift), winters were colder, the climate was drier, and the environmental stresses increased. Finally, with the quite strong or complete zonality associated with Northern Hemisphere deglaciations (little or no Drift), extreme aridity often reduced the inhabitable area of the coastal zone. When each Eurasian deglaciation was completed, the isolation was probably briefly interrupted, as it was in the mid Holocene, by a well-watered savanna that developed across the Sahara. The savannas enabled each small and genetically modified population to increase and extend its range southward into the larger Africa. The pulses of evolution are directly related to glacial cycles by way of Earth’s orbital eccentricity and precession of the equinox. The intervals of coastal zone isolation usually lasted almost 22,000 years, which is the time needed for the precession of the equinox to move summer around on Earth’s orbit from one perihelion point to the next where monsoons are strong, and deglaciation and the savannas tend to occur. However, isolations as long as ~76,000 years also are found in the record because Eurasian ice sheet growth sometimes resumed before deglaciation was complete. In the last million years there may have been at least 18 pluvial savanna intervals when populations of new species or sub species of hominids would have extended their range by expanding on the savanna into the larger Africa or Eurasia. Periodic pulses of evolution of primitive hominids probably also occurred much earlier in the Pliocene with brief savannas but without large Northern glaciations. Generation of new species of hominids in the coastal zone and their injection into the larger Africa by savanna connections may therefore have been largely responsible for the abundance of genus Homo and predecessors in the fossil record and for our own Homo sapiens that we know today.


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Author Biographies

Robert Glenn Johnson, University of Minnesota

Department of Earth Sciences, University of Minnesota Minneapolis, Minnesota 55455

Andre Berger, Université catholique de Louvain

Earth and Life Institute, Université catholique de Louvain B-1348 Louvain-la-Neuve, Belgium


deMenocal, P. B. (2004). African climate change and faunal evolution during the Pliocene-Pleistocene. Earth and Planetary Science Letters, 220, 3-24.

Hsu, K. J., Montadert, L., Bernoulli, D., Cita, M. B., Erickson, A., Garrison, R. E., Kidd, R. B., Melieres, F., Müller, C., & Wright, R. (1977). History of the Mediterranean salinity crisis. Nature, 267, 399-403.

Raynal, J. P., Sbihi Alaoui, F. Z., Geraads, D., Magoga, L., & Mohib, A. (2002). The earliest occupation of North-Africa: the Moroccan perspective. Quaternary international, 75(1), 65-75.

Bobe, R., Behrensmeyer, K., & Chapman, R. (2002). Faunal change, environmental variability and late Pliocene hominin evolution. Journal of human evolution, 42(1), 475-497.

Stewart, J. B., & Stringer, C. B. (2012). Human evolution out of Africa: the role of refugia and climate. Science, 335, 1317-1321.

Rossignol-Strick, M. (1983). African monsoons, an immediate climate response to orbital insolation. Nature, 304, 46-49.

Rossignol-Strick, M. (1985). Mediterranean sapropels, an immediate response of the African monsoon to variation of insolation. Palaeogeography, palaeoclimatology, palaeoecology, 49, 237-263.

Rossignol-Strick, M., Paterne, M. M., Bassinot, F., Emeis, K. C., & De Lange, G. J. (1998). An unusual mid-Pleistocene monsoon period over Africa and Asia. Nature, 392, 269-272.

Street-Perrott, F.A., & R.A. Perrott. (1993). Holocene vegetation, lake levels, and climate of Africa. In: Wright, H. E., et al. (Eds.), Global climates since the last glacial maximum (pp. 318-356). Minneapolis, MN: University of Minnesota Press.

Spoor, F. P., Neubauer, S., Steizer, S., Scott, N., Kwekason, A., & Dean, P. (2015). Reconstructed homo habilis type OH7 suggests deep-rooted species diversity in early homo. Nature, 519, 83-86.

Hublin, J. J., Ben-Ncer, A., Bailey, S. E., Freidline, S. E., Newbauer, S., Skinner, M. M., Bergmann, I., Le Cabec, A., Benazzi, S., Harvati, K. & Gunz, P. (2017). Nature, 546, 289-292.

Broecker, W.S. (1991). The great ocean conveyor. Oceanography. 4, 79-90.

Harmattan. (2018). In Encyclopedia Britannica. Retrieved from

Johnson, R. G. (2018). Initiation of the last ice age in Canada by a cascade of oceanic salinity increases. Journal of advances in natural science, 3(1), 237-252.

Berger, A. L. (1978). Long term variations of caloric summer insolation resulting from Earth’s orbital elements. Quaternary research, 9(2), p. 237. (Tabulated results and eccentricity values supplied by personal communication.)

Bartholomew, A. L. (1950). The advanced atlas of modern geography (p. 78). London: Meiklejohn and Son, Ltd.

Vernekar A. D. (1972). Long-period global variations of incoming solar radiation. In: Long-period global variations of incoming solar radiation. Meteorological monograph. 12. Boston, MA: American Meteorological Society.

Ruddiman, F. F., MacIntyre, J., Niebler-Hunt, & Durazzi, J. T. (1980). Oceanic evidence for the mechanism of rapid Northern Hemisphere glaciation. Quaternary research, 17, 135-147.

Ruddiman, F. F., Molfino, B., Esmay, A., & Pokras, E. (1980). Evidence bearing on the mechanism of rapid deglaciation. Climate change, 3, 65-87.

Heinrich, H. (1988). Origin and consequences of cyclic ice rafting in the northeast North Atlantic Ocean during the past 130,000 years. Quaternary research, 29, 143-152.

Stravers, J. A., Miller, G. H., & Kaufman, D. S. (1988). Late glacial ice margins and deglacial chronology for southeastern Baffin Island and Hudson Strait, eastern Canadian Arctic. Canadian journal of earth science, 29, 1000-1007.

Blake, W. (1966). End moraines and deglaciation chronology in northern Canada, with special reference to southern Baffin Island. Geological Survey of Canada. Paper. 66-76.

Johnson, R. G., & Lauritzen, S. E. (1966). Hudson Bay-Hudson Strait Jokulhlaups and Heinrich events: a hypothesis. Palaeogeography, palaeoclimatology, palaeoecology, 117, 123-137.

Bond, G. W., Broecker, W., Johnsen, S., McManus, J., Labeyrie, L., Jouzel, J., & Bonani, G. (1993).

a. Correlation between climate records from North Atlantic sediments and Greenland ice. Nature, 365, 143-147.

Gallup, C. D., Edwards, R. L., & Johnson, R. G. (1994). The timing of high sea levels over the past 200,000 years. Science, 263, 796-800.

Ruddiman, W. F., & McIntyre, A. (1994). Oceanic mechanisms for amplification of the 23,000-year ice-volume cycle. Science, 212, 617-627.

Field, M. H., Huntley, B., & Müller, H. (1994). Eemian climate fluctuations observed in a European pollen record. Nature, 371, 779-783.

Kallel, N., Duplessy, J. C., Labeyrie, L., Fontugne, M., Paterne, M., & Montacer, M. (2000). Mediterranean pluvial periods and sapropel formation over the last 200,000 years. Palaeogeography, palaeoclimatology, paleoecology, 157, 45-58.

Muerdter, D. R. (1984). Low-salinity surface water incursions across the Strait of Sicily during Late Quaternary sapropel intervals. Marine geology, 58, 401-414.

Bryden, H. L., & Kinder, T. H. (1991). Steady two-layer exchange through the Strait of Gibraltar. Deep-sea research, 38 Suppl. 1., 5445-5463.

Reid, L. L. (1979). On the contribution of the Mediterranean Sea outflow to the Norwegian-Greenland Sea. Deep-sea research, 26, 1199-1223.

Greatbatch, R. J., & Xu, J. (1993). On the transport of volume and heat through sections across the North Atlantic: Climatology and the pentads 1955-1959, 1970-1974. Journal of geophysical research, 98, 10125-10143.

Worthington, L. V. (1976). On the North Atlantic Circulation, Johns Hopkins oceanographic studies No. 6 (p. 7). Baltimore, MD: Johns Hopkins University Press.

Arkhipov, S. A., Ehlers, J., Johnson, R. G., & Wright, H. E. (1995). Glacial drainage toward the Mediterranean during Middle and Late Pleistocene. Boreas, 24, 196-206.

Johnson, R. G. (2001). Last interglacial seastands on Barbados and an early anomalous deglaciation timed by differential uplift. Journal of geophysical research, 106 (C6), 11543-11551.

Fairbanks, R. G. (1990). The age and origin of the “Younger Dryas climate event” in Greenland ice cores. Paleoceanography, 5, 937-948.

Esat, T. M., McCulloch, M. T., Chappell, J., Pillans, B., & Omura, A. (1999). Rapid fluctuations in sea level recorded at Huon Peninsula during the penultimate deglaciation. Science, 238, 197-201.

Muhs, D. R., Pandolfi, K. R., Simmons, K. R., & Schumann, R. R. (2012). Sea level history of past interglacial periods from Uranium-series dating of corals, Curacao, Leeward Antilles islands. Quaternary research, 78, 157-168.

Mesolella, K. J., Mathews, R. K., Broecker, W. S., & Thurber, D. L. (1969). The astronomical theory of climate change: Barbados data. Journal of geology, 77, 250-274.

Thunell, R. C., & Williams, D. F. (1982). Paleoceanographic events associated with termination II in the eastern Mediterranaean. Oceanologica acta, 5, 229-233.

Lambeck, K., Yokoyama, Y., Johnston, P., & Purcell, A. (2000). Global ice volumes at the Last Glacial Maximum and early Late Glacial. Earth and planetary science letters, 181, 513-527.

Bard, E., Rostok, T., Turon, J. L., & Gendreau, S. (2000). Hydrological impact of Heinrich events in the subtropical northeast Atlantic. Science, 289, 1321-1324.

Yan, Z., & Petit-Maire, N. (2000). The last 140 ka in the Afro-Asian arid/semiarid transitional zone. Palaeogeography, palaeoclimatology, paleoecology, 110, 217-233.

Tjallingii, R., Claussen, M., Stuut, J. W., Fohlmeister, J., Alexandra, J. J., Bickert, T., Lamy, F., & Ruhl, U. (2008). Coherent high- and low-latitude control of the northwest African hydrological balance. Nature geoscience, 1, 670-675.

Ruddiman, W. F., & McIntyre, A. (1973). Time-transgressive deglacial retreat of polar waters from the North Atlantic. Quaternary research, 3, 117-130.

Johnson, R. G. (1982). Brunhes-Matuyama magnetic reversal dated at 790,000 yr by marine-astronomical correlations. Quaternary research. 17, 135-147.

Johnson, R. G. (2015). Did a bi-polar multi-level oceanic oscillation cause the Little Ice Age and other high latitude climate extremes? Journal of advances in natural sciences, 3(1), 228-236.

Lamb, H. H. (1995). Climate, History and the Modern World (2nd ed., p. 60). Routledge, NY: Johns Hopkins University Press.

Bender, M. L., Fairbanks, R. G., Taylor, F. W., Mathews, R. K., Goddard, J. G., & Broecker, W. S. (1979). Uranium-series dating of the Pleistocene reef tracts of Barbados, West Indies. GSA bulletin, 90, 577-594.

How to Cite
Johnson, R., & Berger, A. (2019). Cyclic Hominid Evolution in A Moroccan-Algerian Coastal Refuge: The Last Million Years. JOURNAL OF ADVANCES IN NATURAL SCIENCES, 6, 444-466.