The Theory of Evolution
Advantages
There is strong scientific evidence - physiological, fossil and
bio-geographical - to support Darwin's ideas
Since the 19th century, when Darwin forwarded his theories advances in
scientific understanding have clarified and reinforced his ideas on natural
selection
Richard Dawkins, and eminent biologist, has shown that life can develop
itself into increasingly complex forms and totally rejects the idea of an
external designer
Evidence from geologists and palaeontologists also support the process of
evolution
Some Christians have used Darwin's theory to reinforce their idea of God as
an ever-working God rather than a God who occasionally 'interferes' in the
universe he created
Some Christians believe that God started the process of evolution. The
probability of life starting by chance, they claim is virtually impossible
Disadvantages
The theory of evolution is criticised for a lack of evidence including
missing links and inconsistencies
*It is a theory and not a fact*
The history of science shows how theories can change and in some cases be
discarded altogether
Creationists also argue that science has limitations and that it has been
very wrong in the past
Science is unable to provide a complete account of the origin of life.
There is still a lack of comprehensive agreement on how natural selection
began
The human brain, which greatly exceeds the demands required by the
evolutionary process, gives credence to the idea that human beings were
made special by God
It only tells us how life originated, it doesn't tell us why. It offers
nothing for the greater understanding about the purpose of life
Interbreeding with Neanderthals gave some of our ancestors distinctive skin
and hair, but also left behind a legacy of disease within our DNA.
Non-African people today carry Neanderthal DNA in their genetic make-up
that is associated with changes in hair and skin, but also with diseases
such as diabetes, Crohn’s and even conditions such as chronic depression
and addictive behaviour.
Modern humans began to leave Africa around 60,000 years ago, encountering
Neanderthals as they moved into Eurasia. Studies in the past few years show
that modern humans interbred with Neanderthals, albeit rarely.
Two new studies released this week revealed part of the legacy of these
interactions, *concluding that the genome, or complete genetic map, of a
modern non-African person contains about two per cent Neanderthal DNA.*
‘These findings provide yet another twist to the hotly-debated Neanderthal
interbreeding story,’ said Museum human origins expert Prof Chris Stringer.
Pros and cons
The studies compared the genome of a Neanderthal with those of hundreds of
modern humans, both from Eurasia, where our ancestors met Neanderthals, and
from sub-Saharan Africa, where there would have been no interbreeding.
The Neanderthal genome comes from the toe bone of a female individual, and
the modern human information comes from data banks of genetic codes.
Modern diseases, ancient roots
It seems unlikely, however, that Neanderthals were living with these
diseases. In their own genomes this DNA would have had a specific function.
But when transferred to a modern human genome, and to people who have
changed their lifestyles over thousands of years, the DNA may have
triggered negative effects.
One effect may be our immune systems overreacting to threats that are no
longer there, such as parasitic worms. This overreaction can cause
‘auto-immune’ diseases, which include lupus and Crohn’s disease.
Many of these diseases may also only show up in later life, something less
likely to affect our ancestors, who died younger.
*Mismatch*
There are large regions of the modern human genome that have no Neanderthal
DNA in them, suggesting other genes we might have inherited have been wiped
out by evolution.
There is also evidence that male children of Neanderthal and modern human
parents had low fertility, suggesting humans and Neanderthals were
nearly *biologically
incompatible*, something that is found today when closely related mammal
species interbreed.
Despite the legacy of Neanderthal interbreeding, Prof Stringer suspects
that mating between the groups {stem 1 and stem 2} was the exception rather
than the norm. The population numbers of both groups were low, meaning they
did not come into contact with each other very often. There were also
differences in appearance and behaviour, likely to have been significantly
greater than between people today.
An Asian Origin for Human Ancestors?
*Myanmar fossil suggests our earliest predecessors may not have come from
Africa* Researchers agree that our immediate ancestors, the upright walking
apes, arose in Africa*. But the discovery of a new primate that lived about
37 million years ago in the ancient swamplands of Myanmar bolsters the idea
that the deep primate family tree that gave rise to humans is rooted in
Asia*. If true, the discovery suggests that the ancestors of all monkeys,
apes, and humans—known as the anthropoids—arose in Asia and made the
arduous journey to the island continent of Africa almost 40 million years
ago.
Until 18 years ago, fossils of every suspected early anthropoid were found
in Egypt and dated to about 30 million years ago. Then, starting in the
1990s, researchers began discovering the remains of petite primates that
lived 37 million to 45 million years ago in China, Myanmar, and other Asian
nations. *This suggested that anthropoids may have actually arisen in Asia
and then migrated to Africa a few million years later*. But
palaeontologists have lacked the fossils to show when and how these
anthropoids trekked from Asia to Africa, says palaeontologist K.
Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh,
Pennsylvania. In 2005, Beard and an international team of researchers
sifting fossils of early fish, turtle, and ancestral hippo teeth from
fossil beds near the village of Nyaungpinle in Myanmar found a molar the
size of a kernel of popcorn. The tooth, dated to about 38 million years
ago, belonged to a new species of ancient primate, which would have been
the size of a small chipmunk. After several more years of arduous
fieldwork, the team has collected just four molars of this primitive
anthropoid, which they named Afrasia djijidae. "It's a difficult place to
work; it took us 6 years to find four teeth," says Beard.
The four molars were enough to show Beard and team leader Jean-Jacques
Jaeger of the University of Poitiers in France that Afrasia was closely
related to another primitive anthropoid that lived at about the same time,
but in Africa—Afrotarsius libycus from Libya. When the researchers examined
the teeth from the two primates under a microscope, they were so similar in
size, shape, and age that they could have belonged to the same species of
primate, says Beard. Such close resemblance between an Asian and African
fossil anthropoid has "never been demonstrated previously," the authors
write online today in the Proceedings of the National Academy of Sciences.
On closer examination, however, the team noticed that the new molars from
the Asian Afrasia were more primitive than those of Afrotarsius from Libya,
particularly in the larger size of a tiny bulge at the back of its last
lower molar. These primitive traits, as well as the greater diversity and
age of early, or "stem," anthropoids in Asia rather than Africa suggest
that this group arose in Asia and migrated to Africa 37 million to 39
million years ago. "Anthropoids didn't arrive in Africa until right before
we find their fossils in Libya," says Jaeger.
The Out-of-Asia scenario may have been complex. The team proposes that more
than one species of anthropoid migrated from Asia to Africa at about this
time, because there are at least two other types of early anthropoids alive
at about the same time as Afrotarsius in Libya, yet they are not closely
related to Afrotarsius or Afrasia. This may be because once they got to
Africa, they found ideal lush conditions with few carnivores and underwent
a "starburst of evolution," says Beard, rapidly giving rise to a number of
new species.
Others agree that if both the new species of primates from Myanmar and
Libya are indeed early anthropoids, they would greatly strengthen the case
for the Asian origins of anthropoids. "If proven, the biogeographical
significance of these results is profound," says palaeontology Richard Kay
of Duke University in Durham, North Carolina. It would show that there was
a major migration of primates and probably other mammals between the two
continents at a time when it was not easy to get across the ancient Tethys
Sea that divided Africa from Asia. And for humans, it would suggest that
our deepest primate roots were in Asia, not Africa.
Still, the similarity between the species rests on just four molars of
Afrasia, Kay notes, although teeth are the most reliable way to measure
relatedness. And some researchers have yet to be convinced that Afrotarsius
in Libya is a stem anthropoid rather than an ancestor of tarsiers, primates
that are not anthropoids and, thus, are more distant relatives. Kay,
however, says the scales are tipping toward an Asian origin. "We've all
heard about Out-of-Africa for human origins," adds Beard. "Now we think
there was an Out-of-Asia migration into Africa first."
Hence the African theory of evolution is biased. KR IRS 241223
---------- Forwarded message ---------
From: Rangarajan T.N.C. <[email protected]>
Date: Sun, 24 Dec 2023 at 07:29
Subject: Fw: Study Offers New Twist in the First Humans - NYTimes
To:
https://www.nytimes.com/2023/05/17/science/human-origins-africa.html?mwgrp=c-dbar&unlocked_article_code=1.IE0.U__N.rPbKctH7DmCj&smid=url-share
Study Offers New Twist in How the First Humans Evolved
A new genetic analysis of 290 people suggests that humans emerged at
various times and places in Africa.
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