This is good but debatable as an equal base does exist to disprove the
heshyam theory as out-of Africa-theory. Long back, I had written against
the Africa theory of migrations. Also extinction of species was everywhere,
which alone gave the vested interest theory so far tried. This article is
not maligning the Yahoo, but proving that there is opposite theory also ( a
line which I am quoting below, was already found on top of yahoo article
also, proving out of africa theory is not so reliable. ) Now:
"Based on 45 long bones from maximally 14 males and 7 females,
Neanderthals' height averages between 164 and 168 (males) resp. 152 to 156
cm (females). This height is indeed 12–14 cm lower than the height of
post-WWII Europeans, but compared to Europeans some 20,000 or 100 years
ago, it is practically identical or even slightly higher."
"Specifically, genes in the LCP [lipid catabolic process] term had the
greatest excess of NLS in populations of European descent, with an average
NLS frequency of 20.8±2.6% versus 5.9±0.08% genome wide (two-sided t-test,
P<0.0001, n=379 Europeans and n=246 Africans). Further, among examined
out-of-Africa human populations, the excess of NLS [Neanderthal-like
genomic sites] in LCP genes was only observed in individuals of European
descent: the average NLS frequency in Asians is 6.7±0.7% in LCP genes
versus 6.2±0.06% genome wide."
"We offer an alternative hypothesis that suggests that hominid expansion
into regions of cold climate produced change in head shape. Such change in
shape contributed to the increased cranial volume. Bioclimatic effects
directly upon body size (and indirectly upon brain size) in combination
with cranial globularity appear to be a fairly powerful explanation of
ethnic group differences."
Did Our Species Evolve in Subdivided Populations across Africa, and Why
Does It Matter?( another west research and there are many thesis, far and
against; and even in those thesis far and against- still they do accept
that they are only hunches and not exact-as I have underlined on top paras
of the theory produced by Mr G)
Eleanor M.L. Scerri,,⁎ Mark G. Thomas,* Andrea Manica,* Philipp Gunz,* Jay
T. Stock,*, Chris Stringer,* Matt Grove,* Huw S. Groucutt,* Axel
Timmermann,* G. Philip Rightmire,* Francesco d’Errico,*, Christian A.
Tryon,* Nick A. Drake,* Alison S. Brooks,* Robin W. Dennell,* Richard
Durbin,* Brenna M. Henn,* Julia Lee-Thorp,* Peter deMenocal,* Michael D.
Petraglia,* Jessica C. Thompson,* Aylwyn Scally,* and Lounès Chikh
We challenge the view that our species, *Homo sapiens*, evolved within
a single population and/or region of Africa. The chronology and physical
diversity of Pleistocene human fossils suggest that morphologically varied
populations pertaining to the *H. sapiens* clade lived throughout Africa.
Similarly, the African archaeological record demonstrates the polycentric
origin and persistence of regionally distinct Pleistocene material culture
in a variety of palaeoecological settings. Genetic studies also indicate
that present-day population structure within Africa extends to deep times,
paralleling a paleoenvironmental record of shifting and fractured habitable
zones. We argue that these fields support an emerging view of a highly
structured African prehistory that should be considered in human
evolutionary inferences, prompting new interpretations, questions, and
interdisciplinary research directions.
The view that *Homo sapiens* evolved from a single region/population
within Africa has been given primacy in studies of human evolution.
However, developments across multiple fields show that relevant data are no
longer consistent with this view.
We argue instead that *Homo sapiens* evolved within a set of interlinked
groups living across Africa, whose connectivity changed through time.
Genetic models therefore need to incorporate a more complex view of ancient
migration and divergence in Africa.
We summarize this new framework emphasizing population structure, outline
how these changes our understanding of human evolution, and identify new
research directions.
The lineage of Homo sapiens probably originated in Africa at least
∼500 thousand years ago ka, and the earliest observed morphological
manifestations of this clade appeared by ∼300 ka . Early H. sapiens fossils
do not demonstrate a simple linear progression towards contemporary human
morphology. Instead, putative early H. sapiens remains exhibit remarkable
morphological diversity and geographical spread. Together with recent
archaeological and genetic lines of evidence, these data are consistent
with the view that our species originated and diversified within strongly
subdivided (i.e., structured) populations, probably living across Africa,
that were connected by sporadic gene flow 1, 3, 4, 5, 6, 7, 8. This concept
of ‘African multiregional’ may also include hybridization between H.
sapiens and more divergent hominins living in different regions 1, 9, 10,
11, 12. Crucially, such population subdivisions may have been shaped and
sustained by shifts in ecological boundaries 7, 13, 14, challenging the
view that our species was endemic to a single region or habitat, and
implying an often underacknowledged complexity to our African origins.
The constellation of morphological features characterizing H.
sapiens is debated. This has strongly impacted on interpretations of recent
human origins by variably including or excluding different fossils from
interpretative analyses. For example, different morphological criteria and
analytical methods have been used to support both a gradual, mosaic-like
process of modernization of our species or, conversely, a punctuated
speciation.
Extant human crania are characterized by a combination of
features that distinguish us from our fossil relatives and ancestors, such
as a small and gracile face, a chin, and a globular braincase. However,
these typical modern human features emerge in a mosaic-like fashion within
the H. sapiens clade. The oldest currently recognized members of the H.
sapiens clade, from Jebel Irhoud in North Africa, have a facial
morphology *very
similar* to extant H. sapiens, as well as endocranial volumes that fall
within the contemporary range of variation. However, their braincase shapes
are elongated rather than globular, suggesting that distinctive features of
brain shape, and possibly brain function, evolved within H. sapiens . Other
early H. sapiens fossils from Florisbad in South Africa (∼260 ka), Omo
Kibish (∼195 ka) and Herto (∼160 ka), both in Ethiopia, are
*morphologically* diverse . This diversity has led some researchers to
propose that fossils such as Jebel Irhoud and Florisbad actually represent
a more primitive species called ‘H. helmei’, using the binomen given
to the Florisbad
partial cranium in 1935 . In a similar vein, the fossil crania from Herto,
which combine a relatively globular braincase with a robust occipital and
large face, were described as the subspecies H. sapiens idaltu because they
fall outside the variation of recent humans.
Ultimately, the processes underlying the emergence of any
‘package’ of derived features diagnostic of early H. sapiens anatomy remain
incompletely understood. However, the data do not seem to be consistent
with the long-held view that human ancestry is derived predominantly from a
single African region hosting a panmictic population. Instead, H. sapiens
likely descended from a shifting structured population (i.e., a set of
interlinked groups whose connectivity changed through time), each
exhibiting different characteristics of anatomical ‘modernity’. The
discovery that the primitive-looking H. naledi dates to between ∼335 ka and
236 ka [28], and that the Broken Hill 1 Homo heidelbergensis skull may date
to ∼300–125 ka [29], also shows that other hominin species in Africa
coexisted with H. sapiens, raising the possibility of African archaic
interbreeding.
Although geographical differences are clear at the continental
scale, localized spatial patterning is harder to discern. Similarities
between regions may have been produced by occasional contact or by
convergent adaptation to common environmental conditions
While scientific theories are subject to refinement as new
evidence emerges, the consensus among the scientific community strongly
supports the concept of human evolution originating in Africa. If there's
new evidence or alternative hypotheses, they would need to undergo rigorous
scientific scrutiny and evaluation to challenge or refine the existing
understanding.
Top of Form
There are ongoing debates and discussions within the scientific
community regarding specific details and nuances of human migration and
evolution.While alternative hypotheses or challenges to the "Out of Africa"
theory exist, they often represent minority viewpoints within the
scientific community and are subject to scrutiny and debate. Some
alternative theories suggest multiple migrations out of Africa or propose
regional continuity in human evolution rather than a single origin point.
The evidence supporting the Out of Africa theory includes: Scientists have
now dated the skull as being 36,000 years old. The great similarity of this
skull to skulls of the same age from Eurasian finds confirms the "Out of
Africa"-hypothesis. Modern humans broke out of their place of origin around
40,000 years ago - from Africa south of the Sahara - and populated the
world. Genetically, the evidence is that all of our ancestors started in
Africa… and, some cousins that went extinct, had evolved into sub-species
or different species, while in the Levant, Europe and Asia, etc. Multiregional
evolution. It is is a model to account for the pattern of human evolution
in the Pleistocene. The underlying hypothesis is that a worldwide network
of genic exchanges, between evolving human populations that continually
divide and reticulate, provides a frame of population interconnections that
allows both species-wide evolutionary change and local distinctions and
differentiation.* **Multiregional" does not mean independent multiple
origins, ancient divergence of modern populations, simultaneous appearance
of adaptive characters in different regions, or parallel evolution*** It is
often misinterpreted, sometimes it seems on purpose. There are alot of
problems with the out of Africa theory. It is a race model number 1 .it is
a replacement theory which did not happen. There are at least 4 Acts of
introgression from Eurasia into African dna. It's likely homo erectus came
from Africa but the others are definately not certain. when you look at
Neanderthals Denisovans interbreeding ect it doesn't make sense. Then
there's interbreeding between modern humans and archaic humans. It's likely
gene flow from Eurasian that already existed made humans into anatomically
modern humans as in homo homo sapiens. Not the other way around. It's much
more likely there were humans species forming at different places close to
the same time. the fossil evidence and gene flow evidence do not align with
the out of Africa model. There are major issues with this model now.
getting worse by the day. I believe the multiregional model is more
accurate and makes more sense.
Genetic and fossil records do not reveal a single point where
modern humans originated, researchers have found.
Experts from the Museum, the Francis Crick Institute and the Max Planck
Institute for the Science of Human History have partnered to untangle the
different lines of ancestry in the evolution of our species, *Homo sapiens*.
They argue that no specific point in time can currently be identified when
modern human ancestry was confined to a limited birthplace. The known
patterns of the first appearance of anatomical or behavioural traits that
are often used to define *H. sapiens *fit a range of evolutionary histories.
Their new paper, published in Nature*,* reviews our current understanding
of how modern human ancestry around the globe can be traced into the
distant past, and which ancestors it passes through during our journey back
in time.
Prof Chris Stringer, co-author and researcher at the Museum, says, 'Some of
our ancestors will have lived in groups or populations that can be
identified in the fossil record, whereas very little will be known about
others.
'Over the next decade, growing understanding of our complex origins should
expand the geographic focus to regions previously considered peripheral to
our evolution, such as Central and West Africa, the Indian subcontinent and
southeast Asia.'
Three key phases in our ancestry are surrounded by major questions,
including:
- 1 the worldwide expansion of modern humans between 40,000 and 60,000
years ago and the last known contacts with archaic groups such as the
Neanderthals and Denisovans
- 2 an African origin of modern human diversity about 60,000 to 300,000
years ago
- & 3 the complex separation of modern human ancestors from archaic
human groups about 300,000 to one million years ago
Co-author Pontus Skoglund from the Francis Crick Institute says, 'Contrary
to what many believe, neither the genetic nor fossil records has so far
revealed a defined time and place for the origin of our species.
'Such a point in time may not have existed, when the majority of our
ancestry was found in a small geographic region and the traits we associate
with our species appeared. For now, it would be useful to move away from
the idea of a single time and place of origin.'
Interdisciplinary analysis of the growing genetic, fossil and
archaeological records will undoubtedly reveal many new surprises about the
roots of modern human ancestry. K Rajaram IRS 26 11 23
---------- Forwarded message ---------
From: 'gopala krishnan' via Thatha_Patty <[email protected]>
Date: Sun, 26 Nov 2023 at 12:51
Subject: How Homo sapiens became the last human species left-FORWARD
To: Patty Thatha <[email protected]>, Iyer <
[email protected]>, Kerala Iyer <[email protected]>,
[email protected] <[email protected]>, Venkat Raman <
[email protected]>, Narayanaswamy Iyer <[email protected]>, N Sekar <
[email protected]>
The Observer-Science-Where did they all go? How Homo sapiens became the
last human species left-FORWARD
Dear friends,
I found the above article appeared in Yahoo opening page today as quite
interesting and thought of forwarding to the groups.
Gopalakrishnan 26-11-2023
At least nine hominin species once roamed the Earth, so what became of our
vanished ancestors?
Sarah Wild,Sat 18 Nov 2023 14.00 GMT
Just 300,000 years ago – a blink in evolutionary time – at least nine
species of humans wandered the planet. Today, only our own, Homo sapiens,
remains. And this raises one of the biggest questions in the story of human
evolution: where did everyone else go?
“It’s not a coincidence that several of them disappeared around the time
that Homo sapiens started to spread out of Africa and around the rest of
the world,” says Prof Chris Stringer, head of human origins at the Natural
History Museum in London. “What we don’t know is if that was a direct
connection.”
There are many theories around the disappearance of our human cousins, and
limited evidence to decipher exactly what happened. But recent studies are
providing tantalising clues.
What we do know is that from about 40,000 years ago, H sapiens was the last
human standing out of a large and diverse group of bipedal hominins. Hypotheses
range from benign, such as H sapiens having better infant survival rates
than other hominins, or climate changes pushing other species to the brink.
Others suggest a more active role, such as H sapiens hunting other humans
or interbreeding with them and assimilating their genetics.
About 300,000 years ago, the first H sapiens populations were springing up
in Africa. They didn’t look like modern humans, but they are more similar
to us than other Homo species. They had tall, rounded skulls with an almost
vertical forehead. They didn’t have the glowering brows of Neanderthals
(Homo neanderthalensis) or the protruding jaw of archaic-looking species
such as Homo naledi. They also had chins; something that no other Homo
species has had (although we don’t know why only H sapiens has the
protuberance).
A reconstruction of the face of the oldest Neanderthal found in the
Netherlands, nicknamed Krijn
A study published in Nature this year exploded the idea that H sapiens
originated from a single place in Africa in one great evolutionary leap. By
analysing the genomes of 290 people, the researchers showed that H sapiens
descended from at least two populations that lived in Africa for 1m years,
before merging in several interactions.
Palaeoanthropologists continue to argue (quite vociferously) over who the
last ancestor of H Sapiens was, but so far there is no conclusive
evidence. Also,
there is no single origin for H sapiens. There are ancient remains of early
H sapiens in Jebel Irhoud in Morocco, Omo Kibish in Ethiopia and Florisbad
in South Africa, suggesting that our species arose from multiple sites.
When H sapiens moved out of Africa is also the subject of debate. Genetic
evidence suggests there was a big foray out of the continent between 80,000
and 60,000 years ago. But it was not the first expedition. A perplexing H
sapiens skull in Apidima in Greece has been dated to being at least 210,000
years old.
We know of several other Homo groups that existed alongside H sapiens
between 300,000 and 100,000 years ago. Some were quite similar to H sapiens.
Stocky Neanderthals endured Europe’s chilly weather and the mysterious
Denisovans eked out an existence in the rarefied air of what is now Siberia
and Tibet, and possibly further afield.
Hominin species were dying out all the time. It’s probably unusual that we
are still around
Homo erectus, the long-legged “cosmopolitan” species – so called because of
the impressive geographical range it spanned – still wandered through parts
of Indonesia; Homo longi (also known as the “Dragon man”) lived in China.
Homo rhodesiensis (also known as Homo bodoensis or Homo heidelbergensis –
scientists continue to debate its name and membership) was alive in central
and southern Africa.
Other species were rather distinct from us: H naledi, with its ape-size
brain, rambled through the woody grasslands of South Africa, and the
diminutive Homo floresiensis and Homo luzonensis lived, breathed and died
on the islands of Flores and Luzon in Indonesia and the Philippines
respectively.
“Hominin species were likely dying out all the time,” says Prof Eleanor
Scerri, head of the human palaeosystems group at the Max Planck Institute
of Geoanthropology in Jena, Germany. “It’s probably unusual that we are
still around.”
Social resilience
For most ancient human species, the fossil record is sparse. H naledi
individuals, for example, are only found at a single site in South Africa.
Some of the other species are known only by a handful of individuals. In
Africa, where H sapiens first emerged, there are surprisingly few Homo
fossils. “We don’t have a very good understanding of what other hominins
were on the landscape in Africa with H sapiens yet,” says Scerri.
However, there is a plethora of data about Neanderthals, including full
genomes extracted from bones. These close relatives roamed Eurasia until
about 40,000 years ago, living in small groups.
Scientists know significantly less about the Denisovans, but what they do
know has reshuffled our understanding of human origins. In 2008, in the
Denisova cave in Siberia, Russian archaeologists found several hominin bone
fragments, including a finger bone and part of a toe. The cold weather had
preserved some of the DNA in the finger bone, which yielded the full genome
of this previously unknown species.
>From Neanderthal and Denisovan genomes, researchers have inferred that they
lived in small groups and frequently interbred. Some population estimates,
based on mitochondrial DNA (inherited maternally), suggest that at their
most abundant there were about 52,000 Neanderthals in Eurasia before they
began to decline. Others suspect that there could have been between 20,000
and 50,000 individuals.
An important advantage that our direct ancestors appear to have had was
population size. “Because of those small population sizes [among
Neanderthals and Denisovans], there was a lot more interbreeding and the
genetics reflects that,” says Scerri. The lack of genetic diversity would
have rendered these populations more susceptible to diseases and thus less
likely to survive.
H sapiens, by comparison, had larger groups and greater genetic diversity. The
consequences of this extend beyond fitness against disease. “In H sapiens,
we see larger social networks extending across the wider landscape,” says
Stringer. “Having wide networks gives you an insurance policy because if
you’re related to people a bit further away, if there is an environmental
crisis – you’re running out of food or water – you can move into their
environments and they’re not enemies, they’re your kin.” Such networks also
allow for the exchange of ideas and innovation, Stringer adds.
This social resilience could have helped H sapiens survive climatic changes
that would have killed off less adaptable individuals and species.
A 2022 study in Nature modelled the ancient climates and ecosystems in
which H erectus, H heidelbergensis and Neanderthals lived and found that
they lost significant portions of their environmental niches before
disappearing.
A larger 2023 simulation, which included six Homo species and the climate
and vegetation over the past 3m years, found that later Homo species were
able to live in a wider range of habitats, particularly H sapiens.
We know now that Neanderthals were very capable, but maybe Homo sapiens was
just slightly more capable
Prof Axel Timmermann, a co-author of this study and director of the IBS
Centre for Climate Physics in Busan, South Korea, believes that H sapiens
outcompeted Neanderthals, ultimately leading to the latter’s demise.
He built a numerical model, outlined in a 2020 paper, that simulated H
sapiens’s spread out of Africa and combined it with available food
sources. Using
this, he tested three hypotheses for the extinction of Neanderthals: that
they were assimilated into H sapiens; that there was a huge climate
catastrophe; or that H sapiens outcompeted them. “It’s only the last one
[competitive exclusion] that is able to contribute to a realistic
extinction of Neanderthals,” Timmermann says.
The model didn’t investigate what the specific competitive advantage may
have been, although it could have included better tools, better offspring
survival rates, or maybe even social hunting, he says.
Interbreeding human species
Stringer believes a number of small advantages allowed H sapiens to
outcompete its cousins. “We know now that Neanderthals were very capable,
but maybe H sapiens was just slightly more capable,” he says. Seemingly
small innovations, such as weaving or sewing needles (both were known in
the H sapiens fossil record from 35,000 and 30,000 years ago respectively),
could have tipped the scales in H sapiens’s favour, he says.
“Once you weave, you can make baskets or snare nets… A sewing needle gives
you a better seal [on materials], so you have better-insulated tents and you
can keep your babies warm, which is of course critical for infant survival.”
Larger social networks would also have allowed H sapiens to share such
innovations, he adds.
Another possibility is that H sapiens assimilated its cousins into the gene
pool – and there is genetic evidence that this did happen, although whether
it is responsible for the disappearance of the other species is still
contentious. Some people currently living in Eurasia have up to 2%
Neanderthal DNA. In fact, some geneticists claim they can assemble about
40% of the Neanderthal genome from the sequences of living people.
Meanwhile, populations in Oceania, which comprises Australasia, Melanesia,
Micronesia and Polynesia, have between 2% and 4% Denisovan DNA. Some groups
have an even higher percentage. There’s also the tantalising mystery of an
unknown human ancestor, who contributed between 2% and 19% of their genetic
ancestry to people living in west Africa today.
In 2020, two researchers from the University of California, Los Angeles
obtained the genomes of more than 400 people living in Nigeria, Sierra
Leone and the Gambia. They estimated that the ancient humans interbred with
H sapiens in the region at some point in the last 124,000 years. “This
raises an important philosophical argument,” says Scerri. “Did they really
die out, or are they still with us in some way?”
Prof Rebecca Ackermann, co-director of the Human Evolution Research
Institute at the University of Cape Town in South Africa, says that it
depends on how you define species. This is the source of much debate among
palaeoanthropologists: some recognise many species, while others
acknowledge only a handful. “My take is that they probably weren’t distinct
species,” she says, with the exception of obvious outliers such as
small-brained H naledi. “We should really be talking about them as regional
variants.”
But some groups – whether a different species or not – definitely fared
better than others, with our own direct forebears surviving. This is in
large part because of luck and their behaviour, agree the experts I spoke
to – and is something people living today need to recognise to overcome the
challenges on the horizon.
“Networking is important, the ability to adapt to change is important, and
that’s certainly something we’re all going to face with climate change,”
says Stringer.
“Humanity will be faced with either cooperating in the face of those
crises or competing. And what we see from Neanderthals and H sapiens is
that the groups that cooperated better were the ones that got through.”
Sarah Wild is the author of Human Origins: A Short History, published by
Michael O’Mara Books (£12.99).
My end note-As an observer, the present generation are naturally more
beautiful in appearance. This is by observing old photos or hand drawn
pictures of people.
The height of women has increased remarkably. There were discussions in
newspapers about this, I recollect. Still we can see women with smaller
head and face in proportion to the body
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