I suppose I will start my blog off with a series of works I have written for school. This is a final paper that I did for ecological anthropology. I earned a 95%, because I made the claim that human's are the dominant niche. I still believe that we are, though I recognize that every species is of equal importance. we are just at the top of the food chain, according to my research we attained this rank using cunning intelligence, rather than the traditional use of brute force.
I am left with a wonder about the implications of human dominance. We have dramatically altered the ecosystem. Luckily, mother earth is resilient. I assume that if the world were to "end" because of our actions, the earth would adapt to our changes. The world would end in the sense that humans would no longer exist. But, do we have the power to end all life? Or would it be like the dinosaur extinction? If we cease to be, would this event allow another species to fill the top niche? In any case, if human life were to end, the giant spherical rock we call earth would probably still exist. Provided that we don't accidentally create and detonate an explosive capable of annihilating the planet.
Super Humans: Homo sapien Domination of the Hominid Niche through Innovation
A comparison of AMH and neanderthal
bone structure.
Photo credit:http://tinyurl.com/d6ojrzk
Homo neanderthalensis (Neanderthals) occupied Eurasia for roughly a half a million years. These hominids were well adapted to the colder climates of Eurasia. This is demonstrated in their robust bone structure, short limbs, and large nasal passages (Mellars,1998). These stocky traits limited heat loss by keeping the limbs close to the blood supply. The large nasal passages helped warm and humidify air before allowing it to enter the lungs (Gilligan, 2007). This is in contrast to the gracile, heat adapted anatomically modern humans (AMH) who began developing in Africa around 200 kya. AMHs had long limbs, which were ideal for heat loss (Gilligan, 2007). Neanderthals had a larger brain case with an average cranial capacity of 1450 ccs. AMH demonstrate a cranial capacity of 1345 cc. The relatively small difference in cranial capacity does not necessarily indicate that Neanderthals were more intelligent than AMH (Gilligan, 2007). It should be noted that the range of height and width in Neanderthals falls with in the shorter, wider range of AMHs. Neanderthals used the Mousterian techno complex and eventually developed the Châtelperronian techno complex (Gilligan, 2007). AMH used the Aurignacian and Gravettian techno complexes. Neanderthals were top carnivorous predators who likely hunted large game. This is demonstrated through analysis of stable isotope dating, faunal remains, and the comparison of bone injuries to bone injuries that occur in rodeo performers (Hockett & Haws, 2005). AMH were omnivores who exploited a wide range of plant and animal sources (Hocket et al., 2005). Neanderthals were undoubtedly more fit in the environment in Eurasia than AMH.
bone structure.
Photo credit:http://tinyurl.com/d6ojrzk
The Neanderthals went extinct about 30 kya. This event allowed AMH to fill the hominid niche. Currently, there are three main theories as to why the Neanderthals became extinct: climate change, competition for resources with migrating AMH, and DNA admixture of Neanderthals in to AMH. Regardless of what ecological factors caused the demise of the Neanderthals, all three theories suggest that greater innovation by AMH in clothing, diet, and social networks allowed for humans to survive and take over the hominid niche.
Marine isotope stage 3, which occurred from 60kya to 24 kya, was characterized by rapid fluctuations in temperature and wind velocity (Gilligan, 2007). This situation limited the amount of genetic adaptation that could occur. The cold spikes were particularly detrimental to the Neanderthals. These cold spikes included wind velocity spikes and the combination increased the wind chill factor and thus cold stress. If cold stress is allowed to continue for too long hypothermia and eventually death will occur. Hypothermia as a cause of death is undetectable after the victim returns to a normal temperature. It is also undetectable in the skeletal structure of fossilized remains. Clothing can protect against cold stress and can be broken down in to two categories: simple and complex. Simple clothing includes lose clothing that is draped over the wearer while complex clothing is layered and form fitting. Protection from cold stress through the use of clothing is rated in units known as clos. Simple clothing provides 1-2 clos while complex clothing provides 3-5 clos.
It is assumed that the Neanderthals used simple clothing in the form of animal pelts loosely draped over the wearer (Gilligan, 2007). This is inferred through the observation that Neanderthals were cold adapted. If they were using clothing that provided adequate protection from cold stress there would be no evolutionary force selecting for cold adaptation because a less fit wearer would not die from cold stress. It is assumed that AMH used complex clothing because they remained heat adapted after they migrated in to Eurasia. Other factors such as, the discovery of needles and buttons at AMH sites provide evidence that AHM were using complex clothing.
Infants and
young children are far more susceptible to hypothermia. If the Neanderthals
could not adequately protect their offspring from cold stress the rate of
infant mortality would increase. This in turn would cause the population to
decrease as fewer individuals make it to reproductive age. In contrast, if AMH
were using clothing to protect their infants from cold stress their fertility
rates would increase or at least stay constant (Gilligan, 2007). The use of
complex clothing is a clear example of an AMH innovation that protected them
from mortality.
The MIS 3
rapid climate fluctuations inevitably altered the amount of flora and fauna in
any given period. Early humans would need to adjust their hunting and gathering
practices to account for changes in available energy sources. It is documented
that the Neanderthals were top predators who mainly consumed large game. While
AMH consumed a wide range of plant and animal sources (Hockett et al., 2005).
It is well documented in current nutritional science that meat sources provide a large amount of macronutrients while plant sources provide a large amount of micronutrients. Micronutrients are often involved in the extraction of kilocalories (Kcals) from macronutrients. Without micronutrients the dense amount of calories in, for example, bone marrow, would be wasted when a lack of niacin rendered the TCA cycle ineffective (Hockett et al., 2005). Furthermore, it is known that consuming a wide variety of foods increases life span and helps women have safer pregnancies and healthier babies. That is, combining adequate Kcal consumption with adequate vitamin and mineral consumption decreases mortality along the lifespan. This increases the fertility rate by allowing more individuals to survive to reproductive age (Hockett et al., 2005).
The ability to exploit a wider range of sustenance protects the individual from starving in time when large game is scarce (Hockett et al., 2005). Research shows that Neanderthals often endured famine and routinely underwent times of small-scale extinction in specific sites. However, that isn’t to say their highly specialized diet was completely ineffective. The Neanderthals survived in for 500,000 years, which is a very long time. Furthermore, big game yields a high Kcal return for a relatively small amount of work. This strategy was probably quite effective while the Neanderthals had little competition. It seems that their sustenance strategy became less effective once AMH began migrating in to Eurasia. This event created a kind of competition that the Neanderthals had probably never experienced and the pressure coupled with the fact that AMH’s wide diet breadth probably allowed their population size to increase caused a famine the Neanderthals could not recover from.
A wide diet breadth filled with micronutrients from plant sources is a AMH innovation that not only kept them fed in times when big game was scarce but also allowed for increasing fertility rates and decreasing mortality rates. It should be noted that a population of Neanderthals in southern Spain survived until 28 kya or about 5-10 thousand years after the rest of the Neanderthals disappeared. These Neanderthals consumed a wider diet, which included shellfish and plant sources. They also lived north of the Ebro boundary, which kept them isolated from AMH for much longer than other Neanderthals (Hockett et al., 2005).
Neanderthals lived in small groups with large land areas between them. They probably did not engage in trade with other Neanderthal groups nor did they transport valuable resources over long distances. This isolated way of life for Neanderthals contributed to periods of localized extinction (Horan, Bulte, and Shogren, 2004). AMH groups were large with small land areas in between. Groups were part of a larger social and trade network. This social network engaged in the trade of information and ideas as well as raw goods. With in AMH groups members participated in different activities and the settlements had different areas for different functions. AMH created innovations in food procurement, particularly in hunting, and these hunting innovations became a problem for the Neanderthals and their specialized diets. AMH innovations in group organization, culture, trade, and food procurement allowed for direct competitive exclusivity.
DNA admixture
is the theory that the Neanderthals went extinct through interbreeding with AMH
(Wall and Hammer, 2006). It can be loosely tied to the overarching theme of AMH
innovation with the assumption that Neanderthals chose to mate with AMH to
attain the benefits of AMH innovation. Research is in the process of creating a
Neanderthal genome from the mitochondrial DNA extracted from Neanderthal
fossils. However, current data is limited. So far, research indicates that
Europeans have .01-25% Neanderthal DNA. This is not highly suggestive of DNA
admixture (Green, Krause, Ptak, Briggs, Ronan, Simons, Du, Egholm, Rothberg,
Paunovic, and Paabo, 2006). This number may increase as we gather more
Neanderthal loci or it may stay the same. More research is needed on this
theory.
In summary, the
Neanderthals were the closest members of the Homo genus to Homo sapiens who inhabited Eurasia exclusively. The species survived around 500,000 years but became extinct about 30-40 kya. This was around the time AMH entered Eurasia. The Neanderthals were more fit for the Eurasian environment than AMH. However, AMH managed to survive when the Neanderthals perished. There are three theories estimating why the Neanderthals became extinct: climate change, competitive exclusivity with AMH, and DNA admixture. AMH survival was probably due to innovations in clothing, social networks, and energy procurement. The exact cause of Neanderthal extinction may never be known but it was probably a combination of all three theories. Or perhaps it was from an extraneous factor that is yet to be discovered. Whatever the reason is it remains clear that humans used innovation in order to survive. In fact, we are still using innovation to dominate the top niche despite not necessarily being the most fit organism for the environment.
References
Green, R.,
Krause, J., Ptak, S., Briggs, A., Ronan, M., Simmons, J., Du, L., Egholm, M.,
Rotheberg, J.,
Paunovic, M., Paabo, S. (2006). Analysis of one million base pairs of Neanderthal DNA. Nature
444,
330-336
Gilligan, I. (2007). Neanderthal
extinction and modern human behavior: the role of climate change and
clothing. World Archeology 39, 499-514
Hocket, B., Haws, J. (2005). Nutritional ecology and the human demography of Neanderthal extinction.
Quarternary International 137, 21-34
Horan, R., Bulte, E., Shogren, J. (2005) How trade saved humanity from biological exculsion: an
economic theory of
Neanderthal extinction. Journal of
Economic Behavior and Organization 58,
1-29
Mellars, P. (1998). The fate of the Neanderthals. Nature 395, 539-540.
Wall, J., Hammer, M. (2006).
Archaic admixture in the human genome. Current
Opinion in Genetics and
Development
16, 606-610
