A Twist in the Tale of Human Evolution
New DNA research reveals our 'Lord of the Rings' antiquity
What are we and where did we come from? Eternal questions, we may finally
be on the verge of answering. Thanks to the recent remarkable discoveries in
the field of DNA research, we are starting to get a much clearer, if not
stranger picture than we ever could have imagined. For decades there were two main
competing theories, the “Out of Africa” theory and the “Multi-regional”
hypothesis. The study of DNA has shown us that both of these models are at the
same time correct and incorrect. Or more correctly, not exactly the entire
picture. Whilst we still do not have the entire picture yet, the picture that
is emerging is a far more Tolkienesque ancient history, filled with many different
types of weird and wonderful humans, reaching out all over the planet, who were
by no means isolated from each other in time and space, but instead co-existed
and even interbred, creating the new hybrid species that would go on to claim
the Earth for itself. Homo sapien sapien, Humanity.
The Out of Africa theory is the most widely accepted model of the
geographic origin and early migration of anatomically modern humans. The theory
argues for the recent East African origins of modern humans, who left Africa in
one, possibly two waves of migration which populated the world, replacing the older
human species. A first dispersal took place between 130,000–115,000 years ago
via northern Africa, but died out or retreated (although Chinese and some
Australian researchers question this extinction and claim the presence of
modern humans in Australia up to 120,000 years ago and in China at least 80,000
years ago). According to the theory a second dispersal took place via the so-called
Southern Route, which followed the southern coastline of Asia, and colonized
Australia by around 50,000 years ago. Europe and Asia were populated by an
early offshoot which settled the Middle East and India around 40,000 years ago.
Finally the Americas were beginning to be populated possibly as far back as
30,000 years ago.
It was widely believed that in the relative vacuum after the Mount Toba
mega volcano explosion around 60,000 years ago which nearly wiped all forms of
humans from the planet completely, the modern Homo sapiens that remained, out
competed all of the many other forms of archaic humans that also remained.
Largely by being more intelligent, garnering us the ability to be better able
to acquire and defend resources. Other theories postulated that we murdered
them all being more war like (which is a tempting theory considering our modern
tendencies), we were better adapted to climate change and possibly that we had
natural immunities to diseases that they did not.
The Multi regional hypothesis holds that the human species first arose
around two to three million years ago and subsequent human evolution has been
within a single, continuous human species. This species encompasses all archaic
human forms such as Homo erectus and Neanderthals as well as modern forms, and
evolved worldwide to the diverse populations of modern Homo sapiens sapiens.
Now thanks to the recent breakthroughs in the study of DNA, we have to
form a new type of synthesis between the two and add an entirely new element
that until recently was not proven, hybridization. The Victorian era arrogance
of our intellectual superiority leading us to take over the world from the
likes of the supposedly less intelligent Neanderthal cave man, has proven to be
false, we simply did not just out compete or wipe out all the archaic species
of human leaving only us, they are in fact still alive today, inside of us all.
We are them, at least partially. The fact that we were able to interbreed with
the other species of human and have fertile offspring leads us to ask, were we
really different species after all? Or just isolated pockets of the same
species that recombined over time, until we have the truly global society we
have today? This brings us to what is known as the species problem, which
basically means that the definitions of exactly what meets a species
requirements, do not fit all species and are constantly changing, making
species definitions areas of grey, rather than hard and fast lines.
But let’s start at the beginning, we start out around two to three million
years before present, in the species known as Homo erectus or Upright Man. Homo
erectus was the first in our line to harness fire and develop the stone tool
technology we used right up until the Bronze Age, which did not begin until
4,500 and 2,000 BC and is still used today in some regions. It is where we can
truly say we became human, operating as intelligent hunter gatherers, largely
as we always have right up until modern times and as some small pockets of the
world still do.
Until recently it was believed that the species known as Homo habilis
and Homo rudolfensis preceded Homo erectus in the evolutionary scale. That is
until the findings at the Dmanisi site in Georgia, Eastern Europe. An analysis
of the five 1.8 million year old hominid skulls found at Dmanisi, suggests that
the earliest Homo species, Homo habilis, Homo rudolfensis and Homo ergaster and
so forth actually belonged to the same species. “The differences between these
Dmanisi fossils are no more pronounced than those between five modern humans or
five chimpanzees,” said Dr David Lordkipanidze from the Georgian National
Museum in Tbilisi, a lead author of a paper in the journal Science and
co-author of a paper published in the Proceedings of the National Academy of
Sciences. Traditionally, researchers have used variation among Homo fossils to
define different species. But in light of these new findings, Dr Lordkipanidze
and his colleagues suggest that early, diverse Homo fossils, with their origins
in Africa, actually represent variation among members of a single, evolving
lineage – most appropriately, Homo erectus.
“Had the braincase and the face of Skull five been found as separate
fossils at different sites in Africa, they might have been attributed to
different species,” said Dr Christoph Zollikofer from the Anthropological
Institute and Museum in Zurich, Switzerland, a co-author of the Science paper.
That’s because Skull five unites some key features, like the tiny braincase and
large face, which had not been observed together in an early Homo fossil until
now. Given their diverse physical traits, the fossils associated with Skull
five at Dmanisi can be compared to various Homo fossils, including those found
in Africa, dating back to about 2.4 million years ago, as well as others
unearthed in Asia and Europe, which are dated between 1.8 and 1.2 million years
ago. “The Dmanisi finds look quite different from one another, so it’s tempting
to publish them as different species,” Dr Zollikofer said. “Yet we know that
these individuals came from the same location and the same geological time, so
they could, in principle, represent a single population of a single species.” This
seems the most likely scenario.
Homo erectus is generally thought to have originated in Africa two to
three million years ago and spread from there, migrating throughout Eurasia as
far as Southern Europe, Georgia, India, Sri Lanka, China and Indonesia, were it
survived right up until possibly only 30,000 years ago. On the Indonesian island
of Flores in 2003, archaeologists discovered what has become known as the
Flores hobbits or more correctly Homo floresiensis. The remains of an
individual that would have stood about one metre in height was discovered in a
cave at Liang Bua on the island. Partial skeletons of nine individuals have
been recovered from the site, including one complete skull. This hominin had
originally been considered to be remarkable for its survival until relatively
recent times, only 12,000 years ago.
However, more extensive stratigraphic and chronological work has pushed
the dating of the most recent evidence of their existence back to 50,000 years
ago. Their skeletal material is now dated to from 100,000 to 60,000 years ago. Stone
tools recovered alongside the skeletal remains were from archaeological
horizons ranging from 190,000 to 50,000 years ago. Fossil teeth and a partial
jaw from hominins believed ancestral to H. floresiensis were discovered in 2014
and described in 2016. These remains are from a site on Flores called Mata
Menge, about 74 km from Liang Bua. They date to about 700,000 years ago and are
even smaller than the later fossils. The form of the fossils has been
interpreted as suggesting that they are derived from a population of Homo
erectus that arrived on Flores about a million years ago, as indicated by the
oldest artefacts excavated on the island and rapidly there after became dwarfed
through the phenomenon known as insular dwarfism.
It’s worth noting that the Indonesian island of Flores is on the Australian
side of what is known as the Wallace line.
The Wallace Line or Wallace's Line is a faunal boundary line drawn in
1859 by the British naturalist Alfred Russel Wallace that separates the
ecozones of Asia and Wallacea, a transitional zone between Asia and Australia.
West of the line are found organisms related to Asiatic species; to the east, a
mixture of species of Asian and Australian origin is present. Understanding the
biogeography of the region centres on the relationship of ancient sea levels to
the continental shelves. Wallace's Line is visible geographically when the
continental shelf contours are examined; it can be seen as a deep-water channel
that marks the south-eastern edge of the Sunda Shelf which links Borneo, Bali,
Java, and Sumatra underwater to the mainland of south-eastern Asia. Australia
is likewise connected by the Sahul Shelf to New Guinea. The biogeographic
boundary known as Lydekker's Line, which separates the eastern edge of Wallacea
from the Australian region, has a similar origin to the Wallace line. Which
means, if the ancestors of the Flores Hobbits, Homo erectus, could cross one
ocean boundary, why not another and make it further to New Guinea and therefore
Australia?
Unfortunately we do not yet have a sample of Homo erectus or Homo
floresiensis DNA but hopefully with the improvements in analysis techniques and
technology, in the near future we will. From Homo erectus onwards, things start
to get really interesting and at the same time, quite confusing. After
spreading out of Africa, Homo erectus managed to colonize Europe, and Asia where
it seems to have persisted the longest, perhaps being more isolated for a
longer period of time. Somewhere around one million to 800,000 years ago the
Asian Homo erectus populations seems to have split through isolation and
genetic drift from their African forebears, remaining relatively unchanged,
except of course for the Flores Hobbits. However back in Africa things were beginning
to change, in ways that would reshape the world. A new line emerged, having the
mixed features of both Homo erectus and modern humans, most notably a larger
brain.
The new line again pushed out of Africa once more, spanning Europe and Asia,
evolving into what is known as the Denisovan hominid in the east and in west
evolving into the Neanderthal Man. In March 2010, scientists announced the
discovery of a finger bone fragment of a juvenile female who lived about 41,000
years ago, found in the remote Denisova Cave in the Altai Mountains in Siberia,
a cave that has also been inhabited by Neanderthals and modern humans. Three
teeth belonging to different members of the same population have since been
reported. A bone needle dated to 50,000 years ago was discovered at the
archaeological site in 2016 and is described as the most ancient needle known.
Little is known of the precise anatomical features of the Denisovans, since the
only physical remains discovered thus far are the finger bone, two teeth from
which genetic material has been gathered and a toe bone. The single finger bone
is unusually broad and robust, well outside the variation seen in modern
people. Surprisingly, it belonged to a female, indicating that the Denisovans
were extremely robust, perhaps similar in build to the Neanderthals. The tooth
that has been characterized shares no derived morphological features with
Neanderthal or modern humans.
The mitochondrial DNA from the finger bone differs from that of modern
humans by 385 bases (nucleotides) in the mitochondrial DNA strand out of
approximately 16,500, whereas the difference between modern humans and
Neanderthals is around 202 bases. In contrast, the difference between
chimpanzees and modern humans is approximately 1,462 mitochondrial DNA base
pairs. This suggested a divergence time around one million years ago. The
mitochondrial DNA from a tooth bore a high similarity to that of the finger
bone, indicating that they belonged to the same population. From a second
tooth, a mitochondrial DNA sequence was recovered that showed an unexpectedly
large number of genetic differences compared to that found in the other tooth
and the finger, suggesting a high degree of mitochondrial DNA diversity. These
two individuals from the same cave showed more diversity than seen among
sampled Neanderthals from all of Eurasia, and were as different as modern-day
humans from different continents today.
Neanderthals and the Denisovans made advanced tools, apparently kindled
fire on demand, most likely had languages and lived in complex social groups.
The Molodova I archaeological site in eastern Ukraine suggests some
Neanderthals built dwellings using animal bones. A building was made of mammoth
skulls, jaws, tusks and leg bones, and had twenty five hearths inside.
Circumstantial evidence suggests Neanderthals may have been building some form
of watercraft since the Palaeolithic. Scientists have speculated that these
watercraft may have been similar to dugout canoes, which are among the oldest
known boats in the archaeological record. Stone tools discovered on the
southern Ionian Islands suggests that Neanderthals were sailing the
Mediterranean Sea as early as 110,000 years ago. Quartz hand-axes, three-sided
picks, and stone cleavers from Crete have also been recovered that date back
about 170,000 years ago.
It was once thought that Neanderthals lacked the sophistication for
hunting, perhaps scavenging meat from carcasses, but increasing evidence
suggests they were apex predators like us, capable of bringing down a wide
range of prey from red deer, reindeer, ibex and wild boar, to larger animals
such as aurochs and even, on occasion, mammoth, straight tusked elephant and
rhinoceros. However, while they were largely carnivorous, new studies indicate
Neanderthals also had cooked vegetables in their diet. In 2010, an isotope
analysis of Neanderthal teeth found traces of cooked vegetable matter, and more
recently a 2014 study of Neanderthal coprolites (fossilized faeces) found
substantial amounts of plant matter, contradicting the earlier belief they were
exclusively (or almost exclusively) carnivorous. The size and distribution of
Neanderthal sites, along with genetic evidence, suggests Neanderthals lived in
much smaller and more sparsely distributed groups than their Homo sapiens
contemporaries. Some experts suggest that this disparity alone was a major
contributing factor to their ultimate replacement by Homo sapiens, which may
have outnumbered them by as much as 9 to 1 according to some estimates. Their
lower population density may have also increased Neanderthal susceptibility to
mutations caused by inbreeding.
Neanderthals differed from modern humans in that they had a more robust
build and distinctive morphological features, these include shorter limb
proportions, a wider, barrel-shaped rib cage, a reduced chin and, perhaps most
notably, a large nose, which was much larger in both length and width, and started
somewhat higher on the face, than in modern humans. Neanderthals are known for
their sloped forehead and large cranial capacity, which at 1600 cm3 is larger
on average than that of modern humans. One study has found that Neanderthal
brains were more asymmetric than other hominid brains. A 2013 study of
Neanderthal skulls suggests that their eyesight may have been better than that
of modern humans, owing to larger eye sockets and larger areas of the brain
devoted to vision. Evidence suggests they were much stronger than modern
humans, with particularly strong arms and hands, while they were comparable in
height. Neanderthal males averaged 164–168 cm and females 152–156 cm tall.
Samples of 26 specimens in 2010 found an average weight of 77.6 kg for males
and 66.4 kg for females. A 2007 genetic study suggested some Neanderthals may
have had red hair and blond hair, along with a light skin tone. The Denisovans
were most likely similar in build, with their scant remains also being very
robust.
Back home in Africa the remaining late Homo erectus or Homo
heildelbergensis was on the way to becoming us, Homo sapiens. By around 200,000
years ago we emerge in the Great Rift Valley as anatomically modern humans
after breaking off from the Denisovan populations around 800,000 years before
and the Neanderthal populations by around 350,000 years ago. According to the
old theories anatomically modern humans then eventually go on to colonize the
world, out smarting, or killing the previous inhabitants. But is that really
true? Or merely a reflection of our Darwinist philosophy of survival of the
fittest and our Abrahamic philosophy of the world being created for us to
dominate? Since it has been shown that we in fact interbred with archaic forms
of Homo, it may be that we simply out bred them.
Some researchers have postulated that the interbreeding was forced as in
the case of Neanderthal DNA which is present in everyone outside of sub-Saharan
Africa being from female Neanderthals only. Simply assuming that early humans were
brutish cave men who raped everything they could, I think comes back to our
modern attitudes more than any actual evidence. More likely we interbred both
ways in cultural exchange, with the Neanderthal’s offspring being infertile or
less fertile, as is often the case with interbreeding. This over time would
decimate an already endangered population such as the Neanderthal.
This is where the “Multi-regional” model comes back in. Whilst it is
accepted that Homo erectus first evolved in Africa, once it had evolved into
different species in different parts of the world, evolving new genes, and the
fact that we interbred with these different homo species outside of Africa
shows that a large proportion of our genetic make-up evolved multi-regionally.
So in essence, both the “Out of Africa” and “Multi-regional” models are to a
certain extent correct.
Initial analysis of genomes of modern humans showed that we mated with
at least two groups of ancient humans, the Neanderthals and Denisovans.
Approximately 4% of the DNA of everyone outside of Sub-Saharan Africa, is
shared with Neanderthals. Tests comparing the Denisovan hominin genome with
those of six modern humans – a ǃKung from South Africa, a Nigerian, a
Frenchman, a Papua New Guinean, a Bougainville Islander and a Han Chinese
showed that between 4% and 6% of the genome of Melanesians (represented by the
Papua New Guinean and Bougainville Islander) derives from a Denisovan
population. This DNA was possibly introduced during the early migration to
Melanesia. These findings are in concordance with the results of other
comparison tests which show a relative increase in allele sharing between the
Denisovan and the Aboriginal Australian genome, compared to other Eurasians and
African populations; however, it has been observed that Papuans, the population
of Papua New Guinea, have more allele sharing than Aboriginal Australians.
Melanesians and Aboriginal Australians are not the only modern day
descendants of the Denisovans. David Reich of Harvard University, in
collaboration with Mark Stoneking of the Planck Institute team, found genetic
evidence that Denisovan ancestry is shared by Melanesians, Australian Aborigines,
and smaller scattered groups of people in South-East Asia, such as the Mamanwa,
a Negrito people in the Philippines. A paper by Kay Prüfer in 2013 said that
mainland Asians and Native Americans had around 0.2% Denisovan ancestry.
Tibetans have a region of DNA, haplotype, around the EPAS1 gene that assists
with adaptation to low oxygen levels at high altitude. According to a study
published in Nature in July 2014, this region is also found in the Denisovan
genome. However, not all Negritos were found to possess Denisovan genes, Onge
Andaman Islanders and Malaysian Jehai, for example, were found to have no
significant Denisovan inheritance. These data place the interbreeding event in
mainland South-East Asia, and suggest that Denisovans once ranged widely over
eastern Asia. Based on the modern distribution of Denisovan DNA, Denisovans may
have crossed the Wallace Line, with Wallacea serving as their last refugium. How
this would have affected the resident Flores Hobbits is unknown. Perhaps they
interbred?
In 2016 researchers reported that they had found modern human DNA in the
genome of a female Neanderthal from the Altai Mountains region near the border
between Mongolia and Russia, further backing up that the interbreeding was both
ways. They calculated that the mating must have taken place about 100,000 years
ago. Studies published in March 2016 suggest that modern humans bred with
hominins, including Neanderthals, on multiple occasions. Another study in April
2016 found differences between Homo sapiens and Neanderthal Y chromosomes that,
they postulated, could cause female Homo Sapiens to miscarry male babies that
had Neanderthal fathers. This would explain why no modern man had to date been
found with a Neanderthal Y chromosome.
Melanesians and Australoid populations show evidence of only one
interbreeding event, possibly 100,000 years ago, occurring in the Middle East,
Europeans show a second event, which may also be of Middle Eastern origin,
occurring possibly 50,000 years ago, while East Asians show an additional third
interbreeding event possibly 30,000 years ago occurring in Siberia. Evidence
that Neanderthal genomic material is often found amongst genes of the immune
system suggests that some of the interbreeding may have secured resistance to
diseases that Neanderthal populations had bred resistance to.
A detailed comparison of the Denisovan, Neanderthal, and human genomes
has revealed evidence for a complex web of interbreeding among the lineages.
Through such interbreeding, 17% of the Denisovan genome represents DNA from the
local Neanderthal population, while evidence was also found of a contribution
to the nuclear genome from an ancient hominin lineage yet to be identified, 8%
of the Denisovan genome is derived from interbreeding with mysterious unknown
species from Asia one million years ago, which was neither homo
heildelbergensis nor Neanderthal. Most likely Asian Homo erectus.
New research has discovered populations from South and Southeast Asia including
the Australian Aboriginal and Melanesian populations contain a small amount of
ancestral DNA, not present in East Asians or Europeans, suggesting some modern
humans have another, mystery ancestor. The research undertaken by Professor
Jaume Bertranpetit from Pompeu Fabra University in Spain along with a team of
researchers published in Nature Genetics, involved whole-genome sequence
analysis. The genome sequences of 60 individuals of different ethnicities from
India’s mainland were compared with those of 10 Andamanese individuals as well
as publicly available data for other populations. The study found a small
proportion of the genome sequence in populations from South and South East Asia
contained DNA from an unknown, extinct, hominid ancestor. Dr Alan Cooper, from
the University of Adelaide and Australian Centre for Ancient DNA said, “We
already knew there was another species or group of hominids in Southeast Asia
who had contributed to the Denisovan genome. This paper further confirms that
one other group, maybe the same one, has contributed to modern humans.”
In Africa in 2011, researchers found yet another example of
interbreeding with an unknown hominid, likely to be late African Homo erectus
or Homo heildelbergensis, after finding three candidate regions with
introgression by searching for unusual patterns of variations—indicating a
different origin—in 61 non coding regions from two hunter gatherers (Biaka
Pygmies and San, shown significant for admixture in the data) and one West
African agricultural group (Mandinka, shown not significant for admixture in
the data), researchers concluded that roughly 2% of the genetic material found
in some Sub-Saharan African populations was inserted into the human genome
approximately 35,000 years ago from archaic hominins that broke away from the
modern human lineage around 700,000 years ago. After a survey for the
introgressive haplotypes across Sub-Saharan populations, it was suggested that
the admixture event happened with archaic hominins that possibly once inhabited
Central Africa.
In 2012, researchers studied high-coverage whole-genome sequences of
fifteen Sub-Saharan hunter-gatherer males from three groups, five Pygmies
(three Baka, a Bedzan, and a Bakola) from Cameroon, five Hadza from Tanzania,
and five Sandawe from Tanzania. Finding signs that the ancestors of the hunter gatherers
interbred with one or more archaic human populations, probably over 40,000
years ago. They also found that the median time of the most recent common
ancestor of the fifteen test subjects with the putative introgressive
haplotypes was 1.2–1.3 million years ago.
It may turn out in the near future, with further and better testing that
there were even more “other” humans in our lineage, who knows? We are still
just scratching the surface. The more we look, the stranger our DNA and the ancient
world seem to become. Unfortunately today’s world is preoccupied with wars and
consumerism, so there is very little funding for research into one of the most
important aspects of our existence, human history and evolution. Perhaps the
powers that be (who happen to write and control the history books) like keeping
us obfuscated to our true origins and history, therefore more easily controlling
the culture. Too often the true depth of our history is passed off as
“pre-history,” obscure and unimportant. The history we are presented as
important starts with the dominator form of culture, as if that is all there
has ever been. Wars, conquests and tyrants mark our greatest achievements. If
only people knew there was so much more.
So where does this leave us today? Continuing to hold on to outdated
notions born out of largely old fashioned racial bias, or dropping all that
nonsense and accepting that all of us are simply hybrids. Mutts, mongrels, half
casts and Alley Apes. Can we really hold to notions of “racial purity” when
every single one of us are hybrids, mixed breeds? Seems rather silly doesn’t
it. Maybe the problem is in how we
classify things? The DNA evidence is showing us that in reality, all the way
back to Homo erectus, we are one sputtering and spurting, cross mingling surge
of humanity. In us, anatomically modern humans, Homo sapien sapien, we today
contain the genetic material of two different unknown homonids (that we know of
so far), most likely in the Asian and Australian case, late Asian Homo erectus
or potentially Homo floresiensis. In the African case late Homo erectus,
otherwise known as Homo heildelbergensis who we ourselves are evolved from. We
have Neanderthal and Denisovan DNA inside us. That leaves us genetically
covering pretty much the entire spectrum of the Homo/human experience, all the
way back to two to three million years ago and are currently now undergoing the
greatest global melting pot society, social experiment in human history. In
reality, all of humanity, right from the very start until today, are one people. It’s just sometimes we lose
touch with each other for a while, before getting back together.
Perhaps even still today, the “other” humans exist out there in the some
of the hidden, unexplored corners of our beautiful blue planet. Ancient legends
from all around the world that continue right up until this day of the Yeti,
Sasquatch, Yowie, Alma, Orang pendek, Ebu gogo, and other such strange wild men
of the forest come to mind. It turns out, our ancestor’s tales of meeting
“other” types of humans, the hairy men wasn’t just tall tales and silly
superstitions after all. Our DNA is now showing us that our forebears did in
fact meet “other” species of humans all over the world, and even more than
that, they got it on in the bedroom, or cave, or where ever it was. That’s not
important, what’s important is they were telling the truth, that the ancient
legends are true. Whether the hairy men of legend still exist today is
disputed, but many still have close encounters and sightings all around the
world every year. Where there is smoke, there is usually fire. Man make fire.
Where we all go in the future is anyone’s guess. The fact is we cannot
continue the way we currently are, it is quite simply unsustainable. We need to
look back at what brought us here, we need to learn from our mistakes. Perhaps
we should reconsider the only way of life that has been successful and stable
over millions of years, the way of life that allows other ways of life to also
share the planet, the way of life that allows us to live on the Earth without
destroying it? Hunter gathering and sustainable food forest permaculture has
shown to be able to sustain people at relatively stable levels for millions of
years, invented by Homo erectus and still used successfully by many people
today. In the very near future we may have no choice. A society based on the
premise of its ability to grow until infinity (only truly benefiting the elite),
on very finite recourses… Sounds like a mix for disaster.
About the author: Brett Lothian is an Australian author, professional
arborist, market gardener and ethnobotanist. He is the author of the Tricho
Serious Ethnobotany blog and creator of the Trichocereus Cacti Appreciation
group, the Peyote Appreciation group and the Ethnobotany Appreciation Society
group on facebook.
References:
Recent African origin of modern humans
https://en.wikipedia.org/wiki/Recent_African_origin_of_modern_humans
Multiregional origin of modern humans
https://en.wikipedia.org/wiki/Multiregional_origin_of_modern_humans
Homo
https://en.wikipedia.org/wiki/Homo#Species
Timeline of human evolution
https://en.wikipedia.org/wiki/Timeline_of_human_evolution
Homo erectus
https://en.wikipedia.org/wiki/Homo_erectus
Homo floresiensis
https://en.wikipedia.org/wiki/Homo_floresiensis
Wallace Line
https://en.wikipedia.org/wiki/Wallace_Line
Homo heidelbergensis
https://en.wikipedia.org/wiki/Homo_heidelbergensis
Neanderthal
https://en.wikipedia.org/wiki/Neanderthal
Denisovan
https://en.wikipedia.org/wiki/Denisovan
Neanderthal extinction
https://en.wikipedia.org/wiki/Neanderthal_extinction
Archaic human admixture with modern humans
https://en.wikipedia.org/wiki/Archaic_human_admixture_with_modern_humans
Mystery genes – do we have an unknown ancestor? By Shannon Verhagen
http://www.australiangeographic.com.au/news/2016/07/mystery-human-ancestor
Homo sapiens interbred with THIRD species of hominin on way to
Australia: DNA study finds mystery new ancestor. By Mark Prigg
http://www.dailymail.co.uk/sciencetech/article-3707766/Mystery-ancient-human-ancestor-DNA-Andamanese-tribe-Experts-say-previously-unknown-extinct-hominin-bred-human-migration.html
Pre-modern humans may have picked up genes from Homo erectus. By John
Timmer
http://arstechnica.com/science/2013/12/pre-modern-humans-may-have-picked-up-genes-from-homo-erectus/
Archaic admixture in Africans. By Peter Frost
http://evoandproud.blogspot.com.au/2010/05/archaic-admixture-in-africans.html
