Our Human Origins Continue to Remain Unclear. There have been several hominin species which all became extinct except our own - Homo Sapiens Sapiens

At this website by various means we seek to defend life, to encourage Christian faith, to promote Catholic tradition, to edify Marriage in its link to the Creator, to encourage families and individuals, and to support missionary disciples of Jesus.  G.S.

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Field work in Archaeology and Paleoanthropology is constantly turning up new evidence, which requires adjusting our theories about human origins, the appearance and extinction of species, and the migration of populations. Here are a number of fascinating links to explore. 

https://www.nhm.ac.uk/discover/homo-erectus-our-ancient-ancestor.html

https://www.nhm.ac.uk/discover/human-evolution.html

https://www.nhm.ac.uk/discover/news/2021/february/modern-human-origins-cannot-be-traced-back-to-a-single-point.html

https://www.nhm.ac.uk/discover/news/2016/february/earliest-evidence-humans-breeding-neanderthals.html

https://www.nhm.ac.uk/discover/news/2018/january/humans-left-africa-40-000-years-earlier-than-we-thought.html

https://www.nhm.ac.uk/discover/news/2019/july/modern-humans-may-have-been-in-europe-150-000-years-earlier-than.html

https://www.nhm.ac.uk/discover/news/2021/february/modern-human-origins-cannot-be-traced-back-to-a-single-point.html

https://www.historymuseum.ca/neanderthal/

https://www.sciencemag.org/news/1996/12/early-human-species-may-have-coexisted-our-own

https://www.cmnh.org/pnas


NATURAL HISTORY MUSEUM

Human origins                 

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/index.html

1,800,000 – 200,000 BC                                          Homo erectus 

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/homo-erectus/index.html

900,000 - 700,000 BC                                               Homo antecessor

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/homo-antecessor/index.html

600,000 - 250,000 BC                                                  Homo heidelbergensis

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/homo-heidelbergensis/index.html

400,000 – 125,000 BC                                                   Homo rhodesiensis

http://humanorigins.si.edu/evidence/human-fossils/fossils/kabwe-1

http://www.bradshawfoundation.com/origins/homo_rhodesiensis.php

400,000 - 35,000 BC                                      Homo sapiens neanderthalensis

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/neanderthals/

http://archaeologyinfo.com/homo-neanderthalensis/

400,000 – present BC                                                         Homo sapiens sapiens   

http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/homo-sapiens/

95,000 – 17,000 BC                                       Homo florensiensis (The Hobbit)

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/homo-floresiensis/index.html

60,000 – 40,000 BC                                                      Denisovans

http://www.nhm.ac.uk/nature-online/life/human-origins/early-human-family/denisovans/index.html

Homo erectus                          
Reconstruction of early Homo erectus

Homo erectus was the first of our relatives to have human-like body proportions, with shorter arms and longer legs relative to its torso. 

H. erectus was also the first hominin known to have migrated out of Africa, and possibly the first to control fire and cook food.

Highly varied and by far the longest-lived of all the human species, H. erectus survived from about 1.8 million years ago in Africa and western Asia to possibly as late as 200,000 years ago in Indonesia.


Key fossils                              Replica fossil skull of 'Turkana Boy', a male Homo erectus aged 9-12 years old.

Although evidence suggests that H. erectus originated in Africa, the first fossils were found in Asia, and it is in Asia where this species survived for so long.

The first H. erectus fossil was found in Java, Indonesia in 1891, and is commonly known as Java Man. By 1940 many more remains had been found there, and in China.

However, the find that has revealed most about this species is ‘Turkana Boy’ from Nariokotome, Kenya. Unearthed in 1984, the skeleton is around 1.5 million years old and represents the most complete ancient human specimen ever discovered

By studying his remains, scientists have concluded that H. erectus did not use trees for safety or as a food source like earlier hominins. Instead, they were a tall species that walked and ran in much the same way as we do.

Successful species?

In terms of species survival, H. erectus is a huge success story. Fossil evidence for H. erectus stretches over more than 1.5 million years, making it the longest surviving species of all our human relatives. Compare this to our own species, Homo sapiens, which has been around for perhaps 400,000 years so far, and we begin to appreciate the ability of this species to survive over a long period with many changes to the environment and climate.

Beyond Africa

Current evidence suggests all hominins before H. erectus lived in Africa. However, almost as soon as this species appears in the fossil record there is evidence it expanded out of Africa into western and eastern Asia and Indonesia.

Migration happens for many reasons but essentially H. erectus probably drifted across northern Africa, across the Sinai region into Asia, when suitable habitats and food sources stretched that far. Meat was an important part of their diet and carnivorous animals often range more widely than herbivores. This, together with their larger body size, helps explain the large geographic range of H. erectus.


 Homo heidelbergensis           
Homo heidelbergensis reconstruction

Homo heidelbergensis is known to have lived from at least 600,000 years ago in Africa and Europe to maybe as late as 250,000 years ago in some areas. 

They routinely butchered large animals, and their fossil remains are often associated with handaxes.

Evidence suggests that African H. heidelbergensis could be the ancestor of our own species, Homo sapiens.

Distinctly human


Replica of the Broken Hill skull from Kabwe, Zambia, the finest known example of Homo heidelbergensis

After 1 million years ago, we see different human species living across Asia and Europe as well as Africa, which are thought of as distinctly human in physique and behaviour. The first fossil identified as H. heidelbergensis was a jaw discovered near Heidelberg, Germany in 1907. Since then various other finds have been made in Europe, Asia and Africa. They show a less projecting face, more prominent nose and a bigger braincase than Homo erectus, but also more primitive features than those of Neanderthals and modern humans.

Some H. heidelbergensis individuals had brain sizes within the modern human range. However, facially they still looked very different from us, with a longer, lower shaped skull, large brow ridge and no chin.

Skilled and organised

Despite this illustration by Angus McBride, we are not sure whether Homo heidelbergensis actively hunted dangerous large animals, but they were certainly skilled at obtaining their meat.

Evidence shows that H. heidelbergensis was an accomplished tool-maker and skillfully butchered large animals. The remains of horses, elephants, deer and rhinoceroses with butchery marks on their bones have been found alongside fossils of this hominin in Southern England and Germany. Whether they actively hunted the animals isn’t known. But, even if they scavenged the carcasses, these hominins were organised enough to drive off dangerous competing animals such as lions, hyenas and wolves.

Common ancestor

Neanderthal and Homo sapiens DNA reveals that they shared a common ancestor about 400,000 years ago. Many scientists think this could have been H. heidelbergensis, giving rise to Neanderthals in Europe and to our species in Africa. And perhaps to the Denisovans in Asia.

Homo rhodesiensis                                               Nickname: Rhodesian Man

Site:       Kabwe, Zambia                  Date of discovery:  1921                Discovered by:   Tom Zwiglaar
Age: Between 300,000 and 125,000 years old                      Species:  Homo heidelbergensis

Searching for metal ore deposits in the limestone caves of Kabwe, Zambia, Swiss miner Tom Zwiglaar  is credited with finding the first early human fossil ever to be discovered in Africa. When Kabwe (also known as Broken Hill) was sent to Arthur Smith Woodward, Woodward assigned the specimen to a new species: Homo rhodesiensis. Today, most scientists assign Kabwe to Homo heidelbergensis.

Kabwe shows features similar to H. erectus such as a low braincase profile (the area towards the back of the skull), large brow ridges, a slight widening of the midface known as the sagittal keel, and a protrusion at the back of the skull named the occipital torus. But Kabwe also resembles modern humans with a flatter, less prognathic face, and larger brain (1300 cubic centimeters).

This skull is one of the oldest known to have tooth cavities. They occur in 10 of the upper teeth.  The individual may have died from an infection related to dental disease or from a chronic ear infection.


Image Credit: Jim Di Loreto and Don Hurlbert, Smithsonian Institution

Bradshaw Foundation

Homo rhodesiensis is an extinct hominin species living between 400,000 and 125,000 years ago. It is known as 'Rhodesian man'. The fossil Kabwe skull is the type specimen of this species, found at Broken Hill in Northern Rhodesia, now Zambia, by Tom Zwiglaar in 1921.

Homo rhodesiensis was robust, with very large brow ridges and broad face. It is also referred to as 'African Neanderthal', although it demonstrates intermediate features between Homo sapiens and Homo neanderthalensis, with a close association to Homo heidelbergensis. It has been argued that it was the ancestor of Homo sapiens idaltu - 'Herto Man' - which itself was the ancestor of Homo sapiens sapiens.


Neanderthals (Homo neanderthalensis)

http://www.nature.com/news/modern-human-genomes-reveal-our-inner-neanderthal-1.14615

Neanderthals began to evolve about 400,000 years ago, and survived in Europe and Asia until around 35,000 years ago. Meanwhile modern humans (Homo sapiens) were evolving in Africa. Thanks to an abundance of fossil evidence, we have a good idea of what Neanderthals probably looked like. The animation above shows a typical Neanderthal man. His large nose and strong


double-arched brow ridge
distinguish him from a modern human. 

 Who were the Neanderthals?

Illustration of a Neanderthal woman. © John Sibbick / Natural History Museum

Hundreds of Neanderthal fossils have been found since the first identified in 1856 in the Neander Valley, Germany, allowing us to build up an almost complete picture of a typical Neanderthal body. 

They had large brains and short, stocky physiques suited to living in cold environments. Their big nose was also adapted to warming and humidifying the air. 

Neanderthals were skilled hunter-gatherers, made and used flint and stone tools, built shelters and controlled fire. They were highly carnivorous but they also ate other foods, although only limited evidence of plant foods survives in the archaeological record. In Mediterranean regions the Neanderthals exploited marine resources such as shellfish and seals, but their use of aquatic foods was certainly more limited than that of modern humans.

Neanderthals behaved strikingly like our own species in some ways. As well as making and wearing clothes and probably also simple jewellery, archaeological evidence also suggests that they buried their dead.

A close relative


Neanderthal burial site at Kebara, Israel. Some scientists believe that such sites suggest that Neanderthals honoured their dead.

Fossil and genetic data suggest that Neanderthals shared a common ancestor with our species around 400,000 years ago, thought by many scientists to be Homo heidelbergensis.  

In 2010, most of the Neanderthal genome was mapped and compared to modern populations of Homo sapiens, revealing that the Neanderthals' relationship to some modern humans was even closer than previously thought. The results showed that people in Europe, Asia and New Guinea have around 2.5% Neanderthal DNA in their genetic code, suggesting Neanderthals interbred with modern humans not long after they spread out of Africa. 

Why did the Neanderthals die out?

All physical evidence of the Neanderthals disappears around 30,000 years ago. Modern humans reached Europe around 15,000 years earlier and it has been suggested that superior brains, language and skills allowed them to prevail over the Neanderthals. However, this may underestimate our relative.

An alternative view suggests that Ice Age climate fluctuations affected European flora and fauna, causing the disappearance of familiar plants and animals, and that modern humans were better able to adapt than Neanderthals.

Homo sapiens

Carolus Linnaeus © Wikimedia

Taxonomy   Homo sapiens

Empire     Eukaryota
                Kingdom     Animalia
                                Phylum       Chordata
                                                Class     Mammalia
                                                                Order     Primates
                                                                                Family     Hominidae
                                                                                                Genus     Homo
                                                                                                                Species       sapiens

Homo sapiens is the most widely dispersed and numerous medium-large size mammal, and the only extant member of the genus Homo.

The type specimen of Homo sapiens is Carl Linnaeus (1707–1778), based on the descriptions in the 10th edition of his Systema Naturae (Linnaeus, 1758).

No single person was recognised as the type specimen until 1959, when William Stearn wrote that "Linnaeus himself, must stand as the type of his Homo sapiens". This was enough to designate Linnaeus as a lectotype - the single name-bearing type specimen for the species Homo sapiens.

Genus characteristics include a high degree of encephalisation and a skeleton adapted to habitual bipedalism. Species traits include:

  • a globular cranial vault
  • supraorbital ridges small or absent
  • a chin on the lower jaw

The origins of humankind on Earth

It is estimated that the first members of the human family (hominins) lived in Africa about 6 or 7 million years ago. They are believed to have been forest-dwelling, perhaps walking upright in the trees or when on the ground. 

In 2001, cranial fossils of Sahelanthropus tchadensis dating to this time were uncovered in Chad, central Africa. The fossils show a combination of ape-like and human-like features, although how closely related Sahelanthropus tchadensis is to humans is the subject of debate.

Over millions of years, distinct species and lineages emerged and radiated across Africa. Among them were the earliest members of the genus Homo, to which modern humans belong. 

Replicas of the remarkably complete Australopithecus sediba fossil skeletons found in Malapa Cave, South Africa in 2010.

The earliest fossil evidence of these ancient humans dates to between 1.9 and 2.4 million years ago, and comes from East Africa, although a human-like form of the species Australopithecus has recently been described from South Africa. Australopithecus sediba is 1.98 million years old and is the most human-like australopithecine yet discovered, with an increased front brain cavity and small teeth.

The emergence of modern humans

Fossil evidence suggests that modern humans evolved in East Africa around 200,000 years ago, since fossils more than 150,000 years old are known from Ethiopia and Kenya. However, genetic data from recent African populations suggests that other regions may also have been important.

One study compared the DNA of modern hunter-gatherers. The results revealed that Namibian and Khomani Bushmen of southern Africa, Biaka Pygmies of Central Africa and the Sandawe of East Africa have the highest levels of genetic diversity in the world for the DNA studied. 

Although genetic studies should be treated with caution when it comes to pinpointing origins, genetic diversity is one indicator of how ancient a people are. In principle the more ancient the population, the more time it has had to build up diversity.

Distribution

Human diversity

Humans occupy most terrestrial environments and are the most abundant medium-sized mammal on earth. Putative early members of the species lineage are known from Africa at more than 250,000 years ago, while examples showing the modern anatomical pattern date from 195,000–100,000 years ago in Africa, and 90,000–120,000 years ago in the Middle East.

The earliest well-dated diagnostic Homo sapiens fossils in Europe, eastern Asia and Australasia date from 40,000–45,000 years, and in the Americas from less than 15,000 years.

Biology

Vitruvian man by Leonardo da Vinci

Morphology

Humans can be distinguished from other living apes by a strikingly enlarged brain, reduced hair coverage on most parts of the body, and by a suite of skeletal and muscular adaptations associated with habitual bipedal locomotion, including the loss of the grasping ability of the foot. Humans are terrestrial bipeds with a limited ability to swim and dive that must be learned.

The species shows strong variation in body size and proportions, and pigmentation, some of which can be related to the wide range of environments in which Homo sapiens lives. Humans exhibit moderate sexual dimorphism in body size.

Nutrition

Humans are opportunistic omnivores, showing remarkable ingenuity in extracting, producing, processing and preserving foods. Humans are the only species that can control or make fire, and cooking is practiced by all known extant human groups.

Regional variations in diet are influenced by availability within a particular environment, by cultural traditions such as food preferences and avoidances, and even genetic factors. Lactase persistence, which allows some people to consume milk and dairy products throughout life, is a recent adaptation to dairy consumption that would only have been useful among populations with a tradition of dairy farming.

Life cycle

Human social structure is highly variable. Traditional arrangements that may be formalised through marriage include monogamous pairs as well as one-male multi female groups and, more rarely, one-female multi-male groups.

Both males and females may disperse from their natal community. Human infants are born in a relatively immature state and remain dependent on adult carers for several years.

Inter birth intervals are relatively short such that females may have multiple dependent offspring at different stages of developmental maturity. Other members of a community or extended family network may contribute to the care of dependent children, including fathers, older siblings and grandparents.

Humans are typically diurnal and sleep in temporary or permanent shelters at night. Family groups often have exclusive use of a shared sleeping space or residence that may serve as a home base for extensive periods.

Behaviour

A shell bead from Skhul Cave in Israel, dated to 100,000 years ago.

The beginnings of modern human cultural complexity can be traced back at least 100,000 years in Africa and the Middle East. African sites have extensive evidence of the use of red iron oxide pigments, for colouring shell beads and (probably also) the human body, while in the Middle East there are cave sites in Israel with shell beads (one is pictured from the site of Skhul), pigments, and human burials with associated grave goods such as deer antlers.

This species is a large-brained biped, tool-making and tool-using, with an ancestral hunter-gatherer lifestyle, now extended to pastoralism, agriculture and industrialised urbanism.

Behaviour includes complex treatment of the dead, and symbolism including:

  • representational art
  • music
  • religious beliefs
  • complex language
  • complex social systems

Conservation

·         An arial view of London showing a range of human activities. © S Humphrey

·         Human activities, associated with a rapidly increasing demand for food, timber, fibre, and fuel have profoundly affected the ecosystems on which humans and other species depend for their well-being.

·         In the past century the scale and complexity of human activity has increased to the point where human activities are threatening other species and also affecting our own wellbeing as a result of environmental degradation and the likelihood of humanly-induced global warming.

Homo floresiensis
(the 'hobbit')

Model of the skull of Homo floresiensis, the small, human-like species nicknamed ‘the hobbit’.

In 2003, archaeologists on the island of Flores, Indonesia, made what has proved to be an extraordinary find. They unearthed the skeleton of a 1m-tall individual, nicknamed ‘the hobbit’, with some human-like features yet a small, chimpanzee-sized brain. Analysis revealed it to be just 18,000 years old. This new human species was named Homo floresiensis and since its discovery other fossils have been found that suggest this strange hominin lived between 95,000 to as late as 17,000 years ago.

Why was the hobbit so small?

Due to its diminutive stature, the first H. floresiensis specimen unearthed is thought by some scientists to be a diseased modern human. However, multiple fossils with similar features have since been found. 

Instead, it appears the hobbit may be an example of ‘island dwarfing’ – an evolutionary response that occurs when populations of large mammals become isolated on an island with a limited food supply and a lack of predators.

A contradiction

H. floresiensis is a puzzling species. The very small brain size, short legs, ape-like wrists and hipbone suggest it is more like an australopithecine (a group living over 2 million years ago) than a human. However, other parts of its anatomy suggest that it is a human species.

Archaeological evidence found in the same cave on Flores indicates H. floresiensis may have used tools and even hunted and controlled fire. Were their small brains somehow reorganised to allow for more human-like behaviour? Or were early modern humans responsible for some of this archaeological evidence?

Yet more questions

The discovery of H. floresiensis has raised many questions - not only about this species, but about the human fossil record in Asia as a whole. Stone tools dating back over 800,000 years have been found on Flores, but we have no other evidence on the island of human evolution between this time and the time of H. floresiensis

Is this species a descendant of Homo erectus, who migrated out of Africa into Asia? How did their ancestors reach the island of Flores? Only modern humans are thought to make boats to purposely cross stretches of water. 

Did H. floresiensis and our species, Homo sapiens, ever come into contact with one another? And what happened to H. floresiensis? Was a volcanic eruption on the island the reason they became extinct? 

The discovery of this species highlights how much still remains to be learnt about human evolution in Asia.

 Denisovans

Molar tooth belonging to a Denisovan, thought to be a new branch of ancient humans that overlapped in time with Neanderthals and modern humans. © MPI-EVA, Leipzig

Denisovans, together with Neanderthals, are our closest extinct relatives. They are a recently discovered group of ancient humans from whom only a few fossil fragments, dated to about 40,000 years ago, have been found. 

Not only did this group exist at the same time as modern humans, remarkable genetic research has revealed that they interbred with some populations.

DNA evidence provides clues

In 2010, scientists analysed limited DNA from a fossilised finger and a molar tooth unearthed in Denisova Cave in the Altai Mountains, Siberia. The initial research suggested they were from a genetically distinct group of ancient humans that shared a common ancestor with modern humans (Homo sapiens) and Neanderthals (Homo neanderthalensis) about 1 million years ago. However, the whole Denisovan genome has now been reconstructed and indicates a closer link to the Neanderthals.

Just as remarkable was the discovery that the Denisovans, as this ancient human group has become known, are related to a particular group of humans alive today – Australasians, who live on some of the islands north of Australia and in Australia itself.

Evidence of interbreeding

The study showed that Australasians share around 5% of their genetic material with the Denisovans. The most plausible explanation is that Denisovans were present further south as well as in Siberia, and that they encountered and interbred with pre-Australasian populations of modern humans migrating from Africa though south east Asia around 60,000 years ago.

If the populations were very small, it wouldn’t take much interbreeding to make a genetic mark. As few as 50 Denisovans interbreeding with 1,000 pre-Australasians could result in their present-day descendants sharing 5% of their genetic material with Denisovans.

Human evolution in Asia

Genetic information suggests that Denisovans may have been part of the Homo heidelbergensis lineage. In Europe, Homo heidelbergensis gave rise to Neanderthals, in Africa they gave rise to us (modern humans), and in Asia, perhaps to the Denisovans.

The link to this particular page found November 26, 2014 can no longer be located. 

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At this website by various means we seek to defend life, to encourage Christian faith, to promote Catholic tradition, to edify Marriage in its link to the Creator, to encourage families and individuals, and to support missionary disciples of Jesus.  G.S.

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© 2004-2021 All rights reserved Fr. Gilles Surprenant, Associate Priest of Madonna House Apostolate & Poustinik, Montreal  QC
© 2004-2021 Tous droits réservés Abbé Gilles Surprenant, Prêtre Associé de Madonna House Apostolate & Poustinik, Montréal QC
 

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