This is a companion discussion topic for the original entry at https://biologos.org/blogs/deborah-haarsma-the-presidents-notebook/on-the-origin-of-our-species-understanding-the-newest-discoveries
Thank you for sharing. Any thoughts about how these bones were dated, as I understand that it has been a somewhat difficult process to give a definite age?
This is an important question given that this site was first discovered in the 1960’s and the specimens were initially estimated to be younger than the current estimate of ~315,000 years. There are various reasons for the earlier erroneous dates. The site was discovered by miners and was not carefully excavated, layer by layer in the manner that characterizes rigorous archeology. Also only a limited number of specimens were dated (I think only one, actually). Finally, the techniques themselves are considerably more refined than they were in earlier days.
In 2004, the principal investigator in this study, J. J. Hublin, obtained the funding to go back with a bulldozer and tractor to move aside 200 cubic meters of mining-debris and begin careful excavation of the site–layer by layer. He and his collaborators identified flint tools that had been heated by fire. This allowed them to use a technique called thermoluminescence which measures a time dependent accumulation of the relative number of trapped electrons since the heating event. Some 14 different determinations were done from the flint found in the same layer as the hominin fossils. In addition, by a different technique, the authors measured the age of tooth enamel of one of the specimens. Finally, by a third technique (which measures isotopic oxygen-18), the investigators determined the approximate age of rodent fossils that were in the same sediment level as the hominin fossils. All three techniques gave ages in the same general range.
So this analysis is much more thorough than anything done before.
Finally, I’d like to emphasize the genetic analysis that I wrote about in the article itself. Although this doesn’t in any way directly provide a way of dating the Moroccan samples, it does provide a totally independent way of providing a minimum age for our species, and that age falls roughly within this same range.
This information that you discuss in this article is very interesting because as you indicate it give a very different picture of how the evolution of humans took place than we had before. Before we had the view that humans evolved step by step in a very linear fashion. This fit well with a step by step view of Darwinian change.
These new findings indicate a non-linear process, which is different from the Darwinian view and in line with ecological processes work. Also new neurological seem to reveal that the human brain works non-linearly.
Humans expect that God works in a linear fashion, because that is the way we do generally. However the evidence seems to indicate that God does not work linearly. If God did, history would be predetermined, but it is not.
God does not act as humans expect God to act. We need to be open through science to how God works and be able to adjust our thinking appropriately.
I agree this is surprising, Roger. The last twenty years of human evolution studies have held many surprises. We scientists, like people in general, tend to think within little boxes. The gene-centered view of evolutionary biology has itself evolved and is now moving outward as though a window has been opened to a much grander view of the process. One of my favorite evolutionary biology books—because it illustrates this shift in such a moving way—is “The Music of Life: Biology Beyond Genes” by the great Oxford physiologist, Denis Noble. Noble writes, “we sometimes seem to have forgotten that the original question in genetics was not what makes a protein, but rather what makes a dog a dog, a man a man” (p.18). The creation of life through evolution is like a symphony, where the wholeness that arises from the many interacting harmonious parts, demonstrates a beauty that one can never appreciate by focusing only on the scribbled notes on a blank page.
We are only now beginning to gather what we need to know regarding the “musical score” associated with our own creation, but as we do, it will take us beyond the notes on a page into the harmony of the symphony itself.
I assume you are referring to this passage in your article: “By sequencing and analyzing the DNA of the 2,000 year old skeletal remains of a juvenile male in South Africa, it is possible to conclude that “his ancestors on the H. sapiens lineage split from those of some other present-day African populations more than 260,000 years ago.” This implies that our species is at least that old. As a result, there is now good reason to think that members of our species were present in various African regions (including, based on the Hublin et al. study, Morocco) close to 300,000 years ago.” - See more at: http://biologos.org/blogs/deborah-haarsma-the-presidents-notebook/on-the-origin-of-our-species-understanding-the-newest-discoveries#sthash.mgtLq7ud.dpuf
In the Science article that you linked, I was curious to hear your thoughts about this passage:
Once Hublin saw the date, “we realized we had grabbed the very root of the whole species lineage,” he says. The skulls are so transitional that naming them becomes a problem: The team calls them early H. sapiens rather than the “early anatomically modern humans” described at Omo and Herto.
I’m just trying to figure out the proper way even to talk about these new facts. Sigh. Is it fair to say that “early H. sapiens” appeared ~300,000 years BP, but the fossils at Omo and Herto ~200,000 years BP are still consider the earliest “anatomically modern humans”?
This is a great question, Jay, since it raises an interesting point about the evolutionary process–do species names really mean anything in the midst of a transition? This is especially challenging when we’re going back in time hundreds of thousands or millions of years so that all we have to go by is: (1) a set of bones from one isolated area and have no representatives from other geographical regions in the same time period, and/or (2) a set of bones from one specific time but no other samples from the same region at different times?
What it really addresses, then is one of the most important predictions of evolutionary theory. If we could make a time-lapse video of our ancestors over a few million years, we would only see a continuum–there is no moment when one species becomes another. Species names are a convenient handle for us at the present moment in earth’s history–but they can become somewhat arbitrary when analyzing past events.
Thank you for your response. I would like to agree3 with you, but experience on this blog seems to point to a different view. When faced with revolutionary results it is easier to gloss over them rather than to take them seriously. This is what Dawkins & Co. seem to be doing. This is what I hear the people at BioLopgos doing.
Part of the problem is that Darwinian evolution is linear, gradual change in a gently curved line. This is what the Selfish Gene is based on and I have yet to hear anyone in BioLogos to criticize the Selfish Gene. Our friend Denis Noble has rejected the Selfish Gene, but when I tried to discuss his ides on this blog, no one was interested.
Real evolution, Jesus ecological evolution is non linear. Christianity grew out of Judaism in a non linear manner. Humans evolved on a non linear manner as did the development of the earth and all of life. Symbiosis is non linear although some aspects of it can be.
Music is beautiful because it combines the physical, rational. and the spiritual. Nature is beautiful for the same reason. It is non linear and triune. .
Bam! Thank you. This is a much clearer way to describe these things to the non-specialist, I think. We are so used to thinking of “species” as fixed categories – dog, cat, bear, chimp – that it is hard to re-orient the mind into recognizing “species” as belonging to a continuum, when it comes to the distant past.
On page 18-21, of “The Music of Life” Denis Noble takes apart one of the most noteworthy quotations from Dawkins’s, “The Selfish Gene”:
Now they swarm in huge colonies, safe inside gigantic lumbering robots, sealed off from the outside world, communicating with it by tortuous indirect routes, manipulating it by remote control.
They are in you and in me; they created us, body and mind; and their preservation is the ultimate rationale for our existence. They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines.
Noble shows beautifully–phrase by phrase–that it is appropriate to take this metaphor and turn it on its head by examining it from the organism’s perspective rather than the gene’s. For example, “sealed off from the outside world” becomes “moulded by the outside world.” And “safe inside lumbering robots” becomes “locked inside highly intelligent beings.” It’s a poignant illustration of the extreme gene-centric bias of Dawkins as opposed to what happens when one examines the very same information from a top-down point of view. Noble’s entire book is one long deconstruction of the Dawkins/Dennett gene-centric manner of thinking about evolution and I personally recommend reading this as a wonderful way to help a person develop a more holistic and much more reasonable way of thinking about the evolutionary process.
This is a point that looks to phenotype changes.
But in terms of microbiology, when we are finally able to mathematically measure genetic propensity for reproductive compatibility, we would be able to estimate the average number of time intervals (individual frames of the movie) it takes to have reproductive incompatibility.
The genetic surprise about the feline branch of the animal kingdom is the great diversity in phenotypes on a genetic substrate that is unusually closely related. I doubt that the marsupials in Australia, which by definition have been isolated from all other mammalian inputs, would be found to be so similar to each other as to make the marsupial equivalents of Ligers and Tions (offspring of Lions and Tigers).