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25 July 2019 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Plant Sciences Congress
At a public seminar, Understanding human evolution through the study of past environments in the Free State, presented by the UFS Department of Plant Sciences, were, from the left, front: Kristen Wroth, Britt Bousman; back: Prof Louis Scott, mentor in the UFS Department of Plant Sciences, and Michael Toffolo.

Florisbad, a thermal spring situated 45 km northwest of Bloemfontein on the edge of a large dry saltpan, is a well-known fossil site that used to be a large lake where giant buffalo, blue wildebeest, and hippos roamed thousands of years ago. Today, this fossil-bearing spring is not only a tourist attraction and a venue for weddings, but also an established quaternary research station that has attracted several palaeo-scientists since the 1930s, following the discovery of a remarkable human cranium and other fauna. 

Studies of past environments 

Three international researchers studying different aspects of archaeology at this and other sites in the Free State, recently presented lectures at the UFS to a multidisciplinary group of academics in plant sciences, geology, geography, and environmental management.

These lectures are part of the ongoing collaboration regarding fossil plant (pollen), fauna, and archaeological studies between the University of the Free State (UFS), the National Museum, and universities abroad.

Florisbad, a key site for understanding the appearance of modern environments as well as modern humans in Southern Africa, is the focus of the investigations of all three visiting scientists, aiming to provide a better understanding of past Free State environments where human evolution has taken place.

Michael Toffolo, a junior research chair from the University of Bordeaux Montaigne in France, focuses on the reconstruction of site-formation processes, palaeo-environments, and ancient human activities based on the study of the micro-morphology of archaeological deposits. He has been working in Southern Africa since 2013. The title of his lecture was: Reconstructing Pleistocene environments in the Free State by looking at the microscopic sedimentary record. 

Fluoride-preserved bones

Florisbad is widely known for the discovery of an archaic modern human skull of c. 260 000 years old. According to Toffolo, the human probably died, and the remains was left at the spring by the hyenas. The bones consequently absorbed fluoride from the spring water, which counteracted decomposition and helped to preserve it. 

Britt Bousman talked about middle and late Pleistocene terraces and archaeology in the Modder River Valley. He has worked in Southern Africa for the past 43 years and started his collaboration with researchers from the UFS and the National Museum in 1985. They have worked together at several sites, investigating palaeo-environments. Bousman teaches Archaeology in the Department of Anthropology at the Texas State University. 

While most scientists study early human records in rock shelters, especially those near the coast where seafood was harvested by prehistoric people, he is one of only a few researchers who studies the evolution of early human behaviour in central South Africa in the context of their activities in the open environment. 

“Rock shelters are good spaces for human behaviour,” says Bousman. He believes, however, that the Modder River area is a better space to study how humans have survived on the land under changing climatic conditions in the long term; for example, how they hunted and slaughtered animals. This can be seen from the many artefacts they left, such as spearheads, scrapers, etc. Interesting animal remains were also found, such as the bones of an extinct giant zebra at the Erfkroon site along the Modder River, with a head measuring 63 cm compared to that of a current zebra, which measures 54 cm. The only complete horn core of an extinct giant wildebeest was also found at the site. 

The first chemists

According to Bousman, technology changed in the Stone Age and included the production of more grinding stones, indicating that humans collected plants and grinded them. Observations of modern plant-collecting activities suggested that not many plant foods needed grinding. Bousman proposes that different plant components may have been grinded for medicinal mixtures, therefore these ancestors may have assumed the role of chemists. 

Kristen Wroth, a postdoctoral researcher in the Geoarchaeology Working Group at the University of Tübingen, Germany, presented a lecture on early human-environment interactions and ancient pyro technology. She uses a suite of micro-archaeological techniques such as phytolith (microscopic plant silica) analysis, micromorphology, and FTIR to understand both human and Neanderthal behaviour and to reconstruct how local environments have changed in space and through time.


News Archive

To tan or not to tan: a burning issue
2009-12-08

 Prof. Werner Sinclair

“Some evidence exists which implies that sunscreens could indeed be responsible for the dramatic rise in the incidence of melanoma over the past three decades, the period during which the use of sunscreens became very popular,” says Prof. Werner Sinclair, Head of the Department of Dermatology at the University of the Free State. His inaugural lecture was on the topic Sunscreens – Curse or Blessing?

Prof. Sinclair says the use of sunscreen preparations is widely advocated as a measure to prevent acute sunburn, chronic sun damage and resultant premature skin aging as well as skin malignancies, including malignant melanoma. There is inconclusive evidence to prove that these preparations do indeed achieve all of these claims. The question is whether these preparations are doing more harm than good?

He says the incidence of skin cancer is rising dramatically and these tumours are induced mostly by the ultra-violet rays.

Of the UV light that reaches the earth 90-95% belongs to the UVA fraction. UVC is normally filtered out by the ozone layer. UVB leads to sunburn while UVA leads to pigmentation (tanning). Because frequent sunburn was often associated with skin cancer, UVB was assumed, naively, to be the culprit, he says.

Exposure to sunlight induces a sense of well-being, increases the libido, reduces appetite and induces the synthesis of large amounts of vitamin D, an essential nutritional factor. The use of sunscreen creams reduces vitamin D levels and low levels of vitamin D have been associated with breast and colon cancer. Prof. Sinclair says the 17% increase in breast cancer from 1981 to 1991 parallels the vigorous use of sunscreens over the same period.

Among the risk factors for the development of tumours are a family history, tendency to freckle, more than three episodes of severe sunburn during childhood, and the use of artificial UV light tanning booths. He says it remains a question whether to tan or not. It was earlier believed that the main carcinogenic rays were UVB and that UVA merely induced a tan. The increase in UVA exposure could have severe consequences.

Prof. Sinclair says the UV light used in artificial tanning booths consists mainly of pure UVA which are highly dangerous rays. It has been estimated that six per cent of all melanoma deaths in the UK can be directly attributed to the use of artificial tanning lights. The use of an artificial tanning booth will double the melanoma risk of a person. “UVA is solely responsible for solar skin aging and it is ironical that tanning addicts, who want to look beautiful, are inflicting accelerated ageing in the process,” he says.

On the use of sunscreens he says it can prevent painful sunburn, but UVA-induced damage continues unnoticed. UVB blockers decrease vitamin D synthesis, which is a particular problem in the elderly. It also prevents the sunburn warning and therefore increases the UVA dosage that an individual receives. It creates a false sense of security which is the biggest problem associated with sunscreens.

Evidence obtained from the state of Queensland in Australia, where the heaviest and longest use of sunscreens occurred, boasted the highest incidence of melanoma in the world. A huge study in Norway has shown a 350% increase in melanoma for men and 440% for women. This paralleled the increase in the use of UVB blocking sunscreens while there was no change in the ozone layer. It did however, occur during that time when tanning became fashionable in Norway and there was an increase especially in artificial tanning.

Prof. Sinclair says: “We believe that sunscreen use does not directly lead to melanoma, but UVA exposure does. The Melanoma Epidemic is a reality. Sunscreen preparations are not the magical answer in the fight against melanoma and the irresponsible use of these preparations can worsen the problem.”

Media Release
Issued by: Mangaliso Radebe
Assistant Director: Media Liaison
Tel: 051 401 2828
Cell: 078 460 3320
E-mail: radebemt.stg@ufs.ac.za
7 December 2009

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