Ice Age: Distinct Hominin Adaptation Essay

Introduction

Ice age adaptations include the Pleistocene, which is divided into four stages. This includes early Pleistocene stage, middle Pleistocene stage, late Pleistocene as well as numerous faunal stages. Pleistocene term is derived from the Greek word plestos kainos, which means most new. Pleistocene is the sixth epoch of Cenozoic Era. The late Pleistocene stage corresponds with the terminal of Paleolithic age.

The Pleistocene dates approximately 1.806 million years ago (Gibbard, P. and van Kolfschoten, T. (2004). The ice age period was characterized with massive ice cover on earth. This explains the frequent glacial activity during that age. Pleistocene climate had characteristic El Nino as well as trade winds. Ice age was characterized with low temperatures. The mean annual temperatures averaged at -6 °C. Other features of this period include increased snow on mountaintops, increased river flow as well as full lakes due to low temperatures experienced at that time.

During this period, oceanic evaporation extent was low due to low temperatures (Gibbard, P. and van Kolfschoten, T. (2004). This resulted to low precipitation in form of rainfall leading to occurrence of dry and extensive deserts. Major events characterizing this period is glaciations, which transformed the earth’s geography as well as plant and animal evolution. Ice age is characterized by distinct hominin adaptation. These adaptations are based on environmental conditions associated with ice and glaciers.

Hominin adaptations during ice age

All organisms develop adaptations to an environment and only the fit survive. This s according to the law of natural selection by Charles Darwin. During the ice age, 30 % of earth was covered by ice. Few plants could withstand the harsh climate. Rainfall was also inadequate leading to development of expansive deserts. This explains why the world experienced minimal plant coverage. Food was scarce and hard to get by. Organisms had to develop adaptations to cope with the environment.

Early australopiths as well as early Homo preferred living in wooded places. The woods acted as shelter. They lived in groups and families. Homo erectus was living in some parts of Africa. Unlike Early Australopiths, Homo erectus lived in open places. They also lived in groups. Due to low temperatures characterizing the ice age, mammals including hominin had some adaptations. These adaptations are categorized into anatomical as well as behavioral in an attempt to curb extinction.

Their skins were literally covered with hair. Scientifically, hair traps air inside the skin pores preventing loss of heat to the surrounding since air is a poor conductor of heat. Tufts of hair kept the hominin species warm (Gibbard, P. and van Kolfschoten, T. (2004). Another adaptations of hominin included massive deposit of fat on adipose tissues. Fat acted as energy stores since fat is a more efficient source of energy compared to other food types. This is so because it produced a lot of ATP when metabolized (Cann, R.L.; Stoneking, M. and Wilson, A.C (1987). The hominin species metabolized fat leading to production of energy in form of heat. Fat also prevented heat loss as it acted as buffer. Cann, R.L.; Stoneking, M. and Wilson, A.C. (1987)

Another anatomical adaptation included development of tall in addition to lean body. This was especially observed in Homo ergaster. In Africa, climate was different compared to Asia and Northern hemisphere. Within the tropics, climate was hot. This led to a difference between the hominin species. African species has less hair on their bodies due to the hot climate. Winds associated with the tropical climate increased evaporation on their bodies creating the necessary coolness. African species has less fat deposit within their skin’s adipose promoting heat loss (Cann, R.L.; Stoneking, M. and Wilson, A.C. (1987).

Neandertals who had a more developed brain also characterize ice age. Their brain capabilities allowed them develop cultural behaviors that helped them cope with ice age climate. They lived in Asia and some parts of Europe. These regions were much colder than Africa. The Neandertals had ability to move on trees as well as on ground. This enabled them live in different environments and climates. For example, when temperatures were exceedingly low, they lived and moved along trees. When temperatures were high, they moved to open habitats. This increased their survival.

Another adaptation of ice age Neandertals is their diverse food variety. They feed on meat, herbs as well as seeds. This increased their food security. Homo species of ice age had some skills to make tools. They made various tools using stone. The stone tools were used for prey hunting as well as digging out roots. Ability to make tools helped the early man cope with changing climatic conditions. Diet flexibility helped the Homo species cope with fluctuating food availability.

With time, Home erectus population increased prompting migration to various parts. Some moved to Eurasia’s temperate regions characterized by cold climate (Ruth, and R. Röthlisberger (2005). They had to adapt to their new climate both anatomically and behaviorally. To escape the cold weather, they started living in caves. Since they lived in groups, they generated heat from their bodies while in the caves. Anatomical adaptations included growth of hair on their bodies as well as increased fat deposits within their adipose tissues (Ruth, and R. Röthlisberger (2005).

Ice age was also characterized by discovery of fire. Homo erectus species discovered fire and its uses. Many theories describe the fire discovery process though all are based on friction. Fire was used to cook, scare away wild animals, provide warmth as well as make tools. The oldest fire hearths date back to approximately 300,000 to 400,000 years ago. Hearths have been discovered in various sites in Germany, Hungary as well as China. Another adaptation of Homo species living during ice age includes wearing of animal hides. This was because of cold weather associated with this period. The animal hides provided warmth and comfort to early man living in some parts of Europe and Asia. Homo species living in this age had some embroidery skills where they used bones as needles. This is evident due to discovery of bone needles that date to thirty thousands years back.

Role of extinction in hominin evolution during Middle-Pliestocene period

Ice age was associated with much low temperatures, which led to diminished plant growth as well as rainfall. This led to extinction of various animals and plants. Large mammals such as mammoths could not cope with reduced plant growth therefore; they became extinct due to food shortage. Extinction did not only affect big mammals, it also affected Hominin species. Originally, hominin species feed on plants matter however; extinction of numerous plants during ice age necessitated introduction of new diets. Man began feeding on flesh as an alternative diet. Plant extinction led to increase of carnivorous animals. Competition was high and only the fittest survived. Man learnt new ways of protecting himself from wild animals using fire and weapons. Plant extinction led to food shortage. Man responded to this by developing tools that could dig plant roots deep in soil. Majority of these tools were made from stone.

Extinction associated with ice age resulted to evolution of man in terms of behavior and anatomy. Man developed a smaller body to reduce food consumption. He also learnt the idea of shelters to escape from wild animals and cold therefore, ice age played a big role in evolution of man.

References

1. Gibbard, P. and van Kolfschoten, T. (2004) “The Pleistocene and Holocene Epochs” Chapter 22PDF (2.96 MiB) In Gradstein, F. M., Ogg, James G., and Smith, A. Gilbert (eds.), A Geologic Time Scale 2004 Cambridge University Press, Cambridge, ISBN 0521781426
2. Cambridge University Press, Cambridge, ISBN 0-521-32370-3, pp. 241–251.
3. Templeton, A. (2002) “Out of Africa again and again” Nature 416: p. 45
4. Eswarana, Vinayak; Harpendingb, Henry and Rogers, Alan R. (2005) “Genomics refutes an exclusively African origin of humans” Journal of Human Evolution 49(1): pp. 1–18.
5. Ruth, and R. Röthlisberger (2005) “Visual stratigraphy of the North Greenland Ice Core Project (NorthGRIP) ice core during the last glacial period” Journal of Geophysical Research 110: (D02108)
6. Cann, R.L.; Stoneking, M. and Wilson, A.C. (1987) “Mitochondrial DNA and human evolution” Nature 325: pp. 31–36
7. Stringer, C.B. (1992) “Evolution of early modern humans” In: Jones, Steve; Martin, R. and Pilbeam, David R. (eds.) (1992) The Cambridge encyclopedia of human evolution