sexta-feira, 9 de março de 2012

Man/ape similarity: evolution or convergence? Did we really evolved from apes?

Man/ape similarity: evolution or convergence (scientific term)? Did we really evolved from ape? Is the human race still evolving?

While all scientific evidence seems to show that humans evolved over time through natural selection, human evolution remains a controversial subject. Despite the evidence, some religious conservatives claim that humans were put on Earth as we are now by God only a couple thousand years ago and all historical evidence like fossils and dinosaur bones are an elaborate joke played on us by God to test our faith. It is true that evolution has not been proven and it is unlikely it will ever be proven. Like most of science, evolution remains a theory.

Most people take human evolution to mean that people evolved from apes or monkeys. Scientific evolutionists do not believe this at all. Evolutionists believe that humans and apes evolved from a common, ape-like, ancestor millions of years ago. The exact animal from which both humans (homo sapiens) and apes evolved has not yet been discovered. For years, this unknown animal has been called the “missing link.” So…if it is missing the question is: why do we do people take it as a certainty? Why is some scientific assumption more reliable than any religious belief if there is allegedly no proof for Adam and Eve there is also no “missing link” visible and certain for all to lean on.

Read more: What did humans evolve from?

“…Evolution Of Man - What is it?

The modern theory concerning the evolution of man proposes that humans and apes derive from an apelike ancestor that lived on earth a few million years ago. The theory states that man, through a combination of environmental and genetic factors, emerged as a species to produce the variety of ethnicities seen today, while modern apes evolved on a separate evolutionary pathway. Perhaps the most famous proponent of evolutionary theory is Charles Darwin (1809-82) who authored The Origin of Species (1859) to describe his theory of evolution. It was based largely on observations which he made during his 5-year voyage around the world aboard the HMS Beagle (1831-36). Since then, mankind's origin has generally been explained from an evolutionary perspective. Moreover, the theory of man's evolution has been and continues to be modified as new findings are discovered, revisions to the theory are adopted, and earlier concepts proven incorrect are discarded.

Evolution Of Man - Concepts in Evolutionary Theory

The currently-accepted theory of the evolution of man rests on three major principles. These principles hinge on the innate ability which all creatures have to pass on their genetic information to their offspring through the reproductive process. An alternative explanation for homology is a common designer. According to this reasoning, the similarities in anatomical features between species point to a blueprint used by a Creator/Designer.

The first tenet is microevolution, the occurrence and build-up of mutations in the genetic sequence of an organism. Mutations are predominantly random and can occur naturally through errors in the reproductive process or through environmental impacts such as chemicals or radiation.

The second tenet of evolution is natural selection. Natural selection is a natural mechanism by which the fittest members of a species survive to pass on their genetic information, while the weakest are eliminated (die off) because they are unable to compete in the wild. Natural selection is often termed "survival of the fittest" or "elimination of the weakest."

The third tenet is speciation, which occurs when members of a species mutate to the point where they are no longer able to breed with other members of the same species. The new population becomes a reproductively isolated community that is unable to breed with its former community. Through speciation, the genes of the new population become isolated from the previous group.

Evolution Of Man - Scientific Evidence

The theory of evolution of man is supported by a set of independent observations within the fields of anthropology, paleontology, and molecular biology. Collectively, they depict life branching out from a common ancestor through gradual genetic changes over millions of years, commonly known as the "tree of life." Although accepted in mainstream science as altogether factual and experimentally proven, a closer examination of the evidences reveal some inaccuracies and reasonable alternative explanations. This causes a growing number of scientists to dissent from the Darwinian theory of evolution for its inability to satisfactorily explain the origin of man.

One of the major evidences for the evolution of man is homology, that is, the similarity of either anatomical or genetic features between species. For instance, the resemblance in the skeleton structure of apes and humans has been correlated to the homologous genetic sequences within each species as strong evidence for common ancestry. This argument contains the major assumption that similarity equals relatedness. In other words, the more alike two species appear, the more closely they are related to one another. This is known to be a poor assumption. Two species can have homologous anatomy even though they are not related in any way. This is called "convergence" in evolutionary terms. It is now known that homologous features can be generated from entirely different gene segments within different unrelated species. The reality of convergence implies that anatomical features arise because of the need for specific functionality, which is a serious blow to the concept of homology and ancestry.

Additionally, the evolution of man from ape-like ancestors is often argued on the grounds of comparative anatomy within the fossil record. Yet, the fossil record indicates more stability in the forms of species than slow or even drastic changes, which would indicate intermediate stages between modern species. The "missing links" are missing… And unfortunately, the field of paleoanthropology has been riddled with fraudulent claims of finding the missing link between humans and primates, to the extent that fragments of human skeletons have been combined with other species such as pigs and apes and passed off as legitimate. Although genetic variability is seen across all peoples, the process of natural selection leading to speciation is disputed. Research challenging the accepted paradigm continues to surface raising significant questions about the certainty of evolution as the origin of man.

Evolution Of Man - The Scrutiny

The theory concerning the evolution of man is under increased scrutiny due to the persistence of gaps in the fossil record, the inability to demonstrate "life-or-death" determining advantageous genetic mutations, and the lack of experiments or observations to truly confirm the evidence for speciation. Overall, the evolution of man pervades as the accepted paradigm on the origin of man within the scientific community. This is not because it has been proven scientifically, but because alternative viewpoints bring with them metaphysical implications which go against the modern naturalistic paradigm. Nevertheless, a closer examination of the evidence reveals evolution to be increasingly less scientific and more reliant upon beliefs, not proof…”

You think perhaps this text was taken from some creationist website? Not quite…
See all here:
(Newspaper headline): “Exceptional Humans Did Not Evolve from Apes

Human exceptionalism received a boost today with the news that human beings apparently did not evolve from apes. From the story:
The skeleton of an early human who lived 4.4 million years ago shows that humans did not evolve from chimpanzee-like ancestors, researchers reported on Thursday. Instead, the missing link — the common ancestor of both humans and modern apes — was different from both, and apes have evolved just as much as humans have from that common ancestor, they said. The researchers stressed that “Ardi” may now be the oldest known hominid, but she was not the missing link. “At 4.4 million years ago we found something pretty close to it,” said Tim White of the University of California Berkeley, who helped lead the research team.
Here’s how the matter was put in another report about the story:
Researchers concluded that both the human branch and the ape branch of the family tree have evolved significantly from its common ancestor, and chimps can no longer be thought of as a “proxy” for that common ancestor.

“…The famous sequence that shows the evolution of man from knuckle-dragging ape to an upright human may be flawed, a new study has revealed.
Researchers who examined the wrist bones of several primate species believe our early human ancestors never used their knuckles to walk like gorillas.
Instead they evolved from other apes who spent most of their time in trees and descended to the ground upright…”

Read more:

“…We have the most robust data I've ever seen on this topic,' said study co-author Daniel Schmitt, from Duke University.
'This model should cause everyone to re-evaluate what they've said before.'
The debate over the origins of human bipedalism has been argued since Charles Darwin's day, dividing into two competing models.
One model 'envisions the pre-human ancestor as a terrestrial knuckle-walker, a behavior frequently used by our closest living relatives, the African apes,' the report said.
The other model traces our two-legged walking to earlier tree-climbing, a mode of locomotion that is used by all living apes.
Supporters of the knuckle-walking origin think we and African apes evolved from a common knuckle walking ancestor. That connection, they contend, is still evident in wrist and hand bone features shared by African apes and by fossil and living humans.
But the new study's lead author, Tracy Kivell from the Max Planck Institute in Germany, contends this theory.
Ms Kivell compared juvenile and adult wrist bones of more than 100 chimps and bonobos, our closest living primate kin, with those of gorillas.
She found the majority of adult chimpanzees and bonobos had special wrist features that most gorillas lacked.
Gorillas wrists 'locked down'
Kivell and Schmitt suggested these features may be absent in gorillas as they knuckle-walk in a fundamentally different way from chimps and bonobos.
Gorillas stride with their arms and wrists extended straight down and locked in what Kivell called 'columnar' stances that resemble how elephants walk.
By contrast, chimps and bonobos walk more flexibly, 'with their wrists in a bent position as opposed to being stacked-up,' she said.
'And with their wrists in bent positions there will be more stresses at those joints.'

A young chimpanzee (left) has flexible wrists for swinging in trees, while a young gorilla (right) has downward facing wrists that are fixed in place
As a result, chimp and bonobo wrists have special features that gorillas lack - little ridges and concavities that serve as 'bony stops' to keep their wrists from over-bending.
The chimpanzees and bonobos have a more extended-wrist way of knuckle-walking which gives them added stability on branches, the researchers concluded.
In contrast, gorillas' 'columnar' style of knuckle-walking is consistent with ground transport.
'Chimps and bonobos spend a lot of time in the trees. And gorillas do not,' Schmitt said.
Kivell and Schmitt think this suggests independent evolution of knuckle-walking behavior in the two African ape lineages.
'Altogether, the evidence leans against the idea that our own bipedalism evolved from a knuckle-walking ancestor,' the pair wrote.
'Instead, our data support the opposite notion, that features of the hand and wrist found in the human fossil record that have traditionally been treated as indicators of knuckle-walking behavior in general are in fact evidence of arboreality.'
In other words, a long-ago ancestor species that spent its time in the trees moved to the ground and began walking upright.

There are no fossils from the time of this transition, which likely occurred about seven million years ago, Kivell and Schmitt said. But none of the later fossils considered to be on the direct human line were knuckle-walkers.
A report on the findings is online in the research journal Proceedings of the National Academy of Sciences.

Read more:

“The truth is that "if" evolution were true, then there should be a large supply of such skeletal remains in the earth; but there is not…If you are of the impression that there are many intermediate ancestors to man, take notice of the following statement by an expert in the field: “The fossils that decorate our family tree are so scarce that there are still more scientists than specimens. The remarkable fact is that all the physical evidence we have for human evolution can still be placed with room to spare inside a single coffin…But hold on, the story gets better. Dr. Johanson gave a lecture at the University of Missouri in Kansas City, Nov. 20, 1986, on Lucy and why he thinks she is our ancestor. It included the ideas already mentioned and that Lucy’s femur and pelvis were more robust than most chimps and therefore, “could have” walked upright. After the lecture he opened the meeting for questions. The audience of approximately 800 was quiet so some creationists asked questions. Roy Holt asked; “How far away from Lucy did you find the knee?” (The knee bones were actually discovered about a year earlier than the rest of Lucy). Dr. Johanson answered (reluctantly) about 200 feet lower (!) and two to three kilometers away (about 1.5 miles!). Continuing, Holt asked, “Then why are you sure it belonged to Lucy?” Dr. Johanson: “Anatomical similarity.” (Bears and dogs have anatomical similarities)…“

Not ancestor to humans

Neither Lucy nor any other australopithecine is therefore intermediate between humans and African apes. Nor are they similar enough to humans to be any sort of ancestor of ours.
A new species of autralopithecine, Australopithecus garhi, was discovered in 1999 in Ethiopia. Even though this ape was said to be more long-legged than Lucy, it is still just an ape.
In 2002, scientists found another missing link-type suspect. They called this fossil, found in East Africa, the Toumai fossil. It was supposed to be “the oldest trace of a pre-human ancestor”. But even some evolutionists who examined it said it was no such thing

“…History is full of frauds and wishful thinking in regard to alleged missing links:
Piltdown man – fraud
Java man - a few teeth, and a few skull and bone fragments
Nebraska man - a pigs tooth
Australopithecene (Lucy) - portrayed with human like hands and feet despite the fact that it is known to have ape like hands and feet, and to have been a knuckle walker…”


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