View of the village of Kuboes, on the border of South Africa and Namibia.
DNA samples were collected from Nama individuals who have historically
lived in the region.
Photo: Brenna Henn/UC Davis
Nama women of Namibia The Nama are an indigenous population known to
carry exceptional levels of genetic diversity compared to other modern
groups.
In an article which passed beneath my radar last May, a team of anthropologists
led by Professor Brenna Henn of the Genome Center at the University of
California, Davis, cast doubt on the theory that modern humans all originated in
a single population in East Africa.
Instead, they propose a model in which early Homo sapiens spread across
Africa forming partially isolated populations, between which there was limited
gene flow by interbreeding.
The earliest split which is still detectable in the DNA of contemporary people
occurred between 120,000 to 135,000 years ago after two or more weakly
genetically differentiated populations had been mixing for hundreds of thousands
of years.
Before creationists start to get over-excited by the news that earlier
scientists might have been wrong about the exact details of the evolution of
modern humans, they should break the habit of a lifetime and find the courage to
read the abstract to the paper in Nature, which makes it clear that the debate
is about the details of our evolutionary origins in Africa. There is no serious
doubt about the truth of that explanation.
Hunter-gatherer people were carving human and other animal tracks in rocks in Namibia during the Later Stone Age (LSA) that began in Southern Africa about 20,000 years ago.
Unlike the Paluxy hoax in America, when crudely forged human tracks were carved by local people on top of dinosaur tracks, to provide souvenirs for gullible tourists during the Great Depression, these carvings are believed to have had cultural significance for the people who carved them.
They depict detailed human footprints interspersed with tracks of hooved animals which are so accurate that experts are able to determine detailed information on the species, age, sex, limbs, side of the body, trackway and relative direction of the tracks.
The carvings are on six rockfaces in the Doro !nawas mountains in Namibia.
The thing about evolution is that it explains how and why an ecosystem shapes and changes the evolution of the species within it and why the evolution of the species within it shapes and changes the ecosystem, all driven in the longer term by changing climate and geology and migration of new species into it.
The key to understanding that is understanding how environmental selectors favour certain variants over others, whether those variants are size, color, ability to find food and mates, or avoid being the prey of predators.
Given that then, we can us the Theory of evolution to predict that the reason Africa's fauna is the way it is today will be found in African geological and geological history and the history of migration into Africa from, mostly, Eurasia.
In his new book, African Ark: Mammals, landscape and the ecology of a continent, Professor Ara Monadjem of the Department of Biological Sciences, University of Eswatini, describes where the African megafauna came from and how they have shaped the African ecosystems, even influencing the evolution of humans, and in so doing have created an environment on which many plants and small animals depend.
His article in The Conversation explains the background to his book. His article is reprinted here under a Creative Commons license, reformatted for stylistic consistency.
From enormous elephants to tiny shrews: how mammals shape and are shaped by Africa’s landscapes
The African elephant is the world’s largest terrestrial mammal.
Africa is the world’s most diverse continent for large mammals such as antelopes, zebras and elephants. The heaviest of these large mammals top the scales at over one ton, and are referred to as megafauna. In fact, it’s the only continent that has not seen a mass extinction of these megafauna.
The continent’s megafauna community includes the world’s largest terrestrial mammal, the African elephant. Adult African bush elephants can weigh as much as 6 tons. Other giants across African continent include hippopotamuses, rhinoceroses and giraffes.
So, it is only in Africa that ecological interactions and dynamics can be studied as they would have been before the sudden and profound flourishing of Homo sapiens over the past 12 000 years; before then, megafauna would have dominated all terrestrial landscapes on all continents. A visit to Africa is, in other words, a visit to our planet’s past.
It’s not just a tale of megafauna and other well-known large mammals. I pay particular attention to small mammals, such as mice, bats and shrews. That’s partly because I have been studying these creatures for the past three decades.
These animals are also generally overlooked by both scientists and the public. But without them, and the ways in which they’ve interacted with each other and with their larger cousins over tens of thousands years, Africa wouldn’t have the richly varied landscapes it does today.
Africa’s mammals are a global treasure that must be protected. However, the lives of local communities are inextricably linked with these mammals and the remaining natural landscapes that harbour their dwindling populations; conservation solutions will require these communities’ active participation and blessing.
In some areas, nature-based tourism may be a viable solution. However, much of the rest of the continent – where no tourists go – will require other, perhaps novel, approaches. What we cannot afford is the extinction of any of these beautiful creatures or the continued loss and reduction of the ecosystem services that they freely provide.
Early mammal history
The history of African mammals begins with an apparently unrelated group of creatures. They’re so dissimilar from each other today that taxonomists didn’t work out their true relationships until about two decades ago. These are the elephants, manatees, elephant shrews, African golden moles, hyraxes and tenrecs. Collectively they make up the super-order Afrotheria.
Today, this group accounts for only a small fraction of the mammal species on the continent. But that is only because Africa – which formed part of the prehistoric southern supercontinent of Gondwana – was colonised, in stages and over millions of years, by ‘invaders’ from the northern supercontinent of Laurasia.
These colonists include nearly all the mammals that we normally associate with Africa, including rhinoceroses, zebras, antelopes, primates, bats and even rodents. In return, some Afrotherians, including elephants, roamed out of Africa to colonise other lands further north.
Other mammals, including monkeys and caviomorph rodents (such as guinea pigs and capybaras), used Africa as a stepping stone to colonise South America, as did lemurs to colonise Madagascar.
Shaped by geography
The variables of physical geography have worked hand in hand with the tectonic forces of prehistory.
Africa is not a uniform landscape that enjoys the same climate and habitat throughout. Some parts, such as Madagascar, are not even connected to the mainland but appear as offshore islands. Terrestrial mammals typically reach islands in two ways: they either raft across the intervening sea, or cross by foot during periods of drier weather or lower sea levels that connect the islands to the mainland.
In the continent’s interior, other formidable barriers restrict and determine mammal movement. Long, deep, fast-flowing rivers, such as the Congo in central Africa, can be almost as effective a barrier as open oceans. Mountain ranges can form inland ‘islands’ that are as ecologically isolated as their ocean equivalents.
By providing barriers, geographical features limit the movement of animals across the landscape, thereby affecting the composition of mammal communities in different parts of the continent.
Population shifts
Another element that’s crucial to telling the story of Africa’s mammals is an understanding of how species and population groups are formed and fluctuate over time.
For example, megafauna play important roles in shaping the landscape and its plant communities. This in turn shapes many smaller animals’ habitats. Hippopotamuses in the Okavango Delta create and maintain open water channels, which serve as critical habitat for fishes. And, by defecating in water, hippos also introduce vast amounts of organic fertiliser into this aquatic ecosystem, helping to enrich it.
Smaller animals, too, shape landscapes.
Some species of rats and mice, such as pouched mice in the genus Saccostomus, are granivores that feed on seeds, including those of trees responsible for bush encroachment in savannas such as the sicklebush. Colleagues and I have shown experimentally that various species of mice in Eswatini actually prefer the seeds of this encroaching plant and hence can assist in controlling its spread. But these rodents require good grass cover for persistence, and hence can’t provide this ecological service in over-grazed, degraded landscapes.
The numbers of animals naturally fluctuate over time, typically reflecting fluctuations in food supply brought about by, for example, droughts or floods. A key determinant of these population fluctuations is also the inherent life history characteristics of a species: short-lived, fast reproducing species such as rats and mice will, by definition, experience greater fluctuations in their numbers than long-lived, slow reproducing species like elephants.
Conservation
My book concludes by looking at human interactions with African mammals and the need to conserve these mammals, both for their own sake and for ours. The ecosystem services provided by many mammals are crucial to a healthy environment for all species. Humans evolved in Africa and have interacted with other African mammals for millions of years here.
This is not true on other continents, where humans are – in geological timescales – a recent addition. It may well be that this long relationship between humans and other African mammals is the reason why, despite the losses wrought by humankind, so many large mammals persist on the continent: they have ‘learnt’ through natural selection how to survive with us.
Published by The Conversation. Open access. (CC BY 4.0)
It happens with such monotonous regularity, with practically every biology paper ever published, that the fact that this article refutes creationist claims is hardly worth mentioning. One day, maybe, someone will tell the cult that they are living in a counter-factual wonderland, completely disconnected from the real world.
Four different Australopithecus crania that were found in the Sterkfontein caves, South Africa. The Sterkfontein cave fill containing this and other Australopithecus fossils was dated to 3.4 to 3.6 million years ago.
Because of the hominin remains found there, the system of caves at Driefontein in Gauteng, South Africa is a designated world heritage site, known as 'The Cradle of Humankind'. It is believed by some to be where modern Homo sapiens evolved out of ancestral hominins.
Driefontein is a cave system located in the Cradle of Humankind, a World Heritage Site in Gauteng, South Africa. The Cradle of Humankind is a paleontological site that is home to some of the world's most important hominid fossil finds, including the fossils of "Mrs. Ples" and "Little Foot."
The Driefontein cave system has been of particular interest to paleontologists because of the discovery of early hominid fossils there. The fossils found at Driefontein date back over 2 million years, and include specimens from several species, including Australopithecus africanus and Paranthropus robustus.
One of the most notable discoveries made at Driefontein was that of the "Little Foot" skeleton, which was found in the Sterkfontein Caves in 1994. Little Foot is an almost complete Australopithecus skeleton, estimated to be around 3.67 million years old, making it one of the oldest hominid fossils ever found.
The Cradle of Humankind is a significant site for the study of human evolution and the history of life on Earth. Its importance has been recognized by UNESCO, which designated it a World Heritage Site in 1999.
ChatGPT.(6 Apr 2023) "Tell me about the Driefontein 'Cradle of Humankind', in South Africa, with references." Retrieved from https://chat.openai.com/chat
"Mrs. Ples" and "Little Foot" are two important hominid fossils found in the Cradle of Humankind in South Africa.
"Mrs. Ples":
"Mrs. Ples" is the nickname given to a fossil skull discovered in 1947 by paleontologist Robert Broom at the Sterkfontein Caves, which are part of the Cradle of Humankind. The fossil is officially known as StW 5, and is believed to be around 2.05 million years old. "Mrs. Ples" is believed to be a member of the species Australopithecus africanus, and is one of the most complete early hominid skulls ever found.
"Little Foot":
"Little Foot" is the nickname given to a nearly complete Australopithecus skeleton discovered in the Sterkfontein Caves in 1994. The fossil is officially known as StW 573, and is believed to be around 3.67 million years old, making it one of the oldest hominid fossils ever found. The discovery of "Little Foot" is significant because it provides important insights into the evolution of bipedalism, or walking on two legs. The skeleton is also notable for being nearly complete, which is rare in the field of paleoanthropology.
ChatGPT. (6 Apr 2023) "Tell me more about the fossils 'Mrs Ples' and 'Little Foot', with references, please." Retrieved from https://chat.openai.com/chat
In the following article, reprinted from The Conversation under a Creative Commons license, Tim Forssman, Senior lecturer, University of Pretoria, South Africa, explains the significance of the site in the story of the evolution of modern humans.
The article has been reformatted for stylistic consistency.
In the west, we tend to minimise the cultural achievements of Africa because it never attained the advanced technological economies Europe and Asia achieved n=my the Late Middle Ages. The factors which caused Africa to remain technologically under-developed include climate, lack of animals suitable for domestication as draught animals and beasts of burden, and the presence of tropical parasites such as the tsetse fly making it difficult to use domestic animals imported from Eurasia.
But despite this there is evidence of sophisticated cultures and political entities such as Great Zimbabwe, Kiliwa and the Kingdom of Mapungubwe, in south Africa, which by 800 CE was trading with China, and India as well as the rest of Africa.
Mapungubwe is a significant cultural site in South Africa, as it was the capital of the Mapungubwe Kingdom, which flourished between the 9th and 13th centuries AD. This kingdom was one of the largest and most complex societies in southern Africa at the time, and its people traded with China, India, and other parts of Africa.
The Mapungubwe Cultural Landscape was declared a UNESCO World Heritage Site in 2003, as it provides insight into the development of African societies before the colonial period. It is also considered a symbol of African cultural identity and the resilience of indigenous cultures in the face of colonialism.
Furthermore, Mapungubwe is considered an important archaeological site, as it has yielded a wealth of artifacts, including gold objects, pottery, and glass beads. These artifacts provide evidence of the advanced technological and artistic skills of the Mapungubwe people and their connections to other parts of the world.
ChatGPT. (2023, April 6). What's the cultural significance of Mapungubwe in South Africa? References, please. [Response to a question on OpenAI]. Retrieved from https://openai.com
In the following article, Tim Forssman, Senior Lecturer, University of Mpumalanga, South Africa, explains how his team are excavating the site in the Mapungubwe National Park and World Heritage Site and the significance of their discoveries, especially how the hunter-gatherers around the city were essential to its continuation and prosperity.
His article is reprinted here under a Creative Commons license, reformatted for stylistic consistency. The original can be read here.
Archaeology shows how hunter‑gatherers fitted into southern Africa’s first city, 800 years ago
Archaeologists excavate inside and outside Little Muck Shelter, in the Mapungubwe National Park, South Africa.
Where the Limpopo and Shashe Rivers meet, forming the modern border between Botswana, South Africa and Zimbabwe, lies a hill that hardly stands out from the rest. One could easily pass it without realising its historical significance. It was on and around this hill that what appears to be southern Africa’s earliest state-level society and urban city, Mapungubwe, appeared around 800 years ago.
After nearly a century of research, we’ve learnt quite a lot about this ancient kingdom and how it arose among early farmer society and its involvement in global trade networks. However, before farmers settled the region, this terrain was the home of hunter-gatherer groups, who have hardly been acknowledged despite, as it seems, their involvement in the rise of Mapungubwe.
My team and I have been working in northern South Africa at sites that we believe will help us recognise the roles played by hunter-gatherers during the development of the Mapungubwe state in a bid to generate a more inclusive representation of the region’s past.
