Thursday, June 04, 2020

An Honest Evolution Debate?

James Haught once wrote a column, now appearing in the Good Men Project on how science is an honest endeavor.  He writes:

To me, the whole issue hinges on honesty. Let me explain: Science, from a Latin word meaning knowledge, is simply a search for trustworthy facts. It is human intelligence at work. The process is honest, because every researcher’s claim is challenged by other researchers. They test and retest by many methods, until a new idea fails or holds firm. (A researcher who falsifies data is a loathsome criminal in the eyes of fellow scientists.)

While some individual scientists are pig-headed, an entire field cannot be. Science goes where the evidence leads. Science is honest enough to admit mistakes. When new evidence shatters a previous assertion, the old belief is dropped or modified. No such setbacks have hit the theory of evolution.

After 140 years of research, virtually the entire scientific world now agrees that evolution is a fundamental aspect of nature.
As you might guess, there are quite a few people who would disagree with this perspective.  It is, nonetheless, true.  

Wednesday, June 03, 2020

Libby Anne: Ken Ham is Playing at Science

She's not wrong.  Libby Anne, a writer for Patheos has latched onto something that has been an issue with Ken Ham for quite some time: he is scientifically ignorant.  One of Ham's persistent arguments is that we can't know historical science (or predictive science) because, as he puts it, “Were You There”? A moment's thought about this perspective reveals it to be facile.  Libby Anne agrees:
Ham argues that some science uses observation and experimentation (what he calls “experimental or observational science”) while other science (what he calls “origins or historical science”) does not. Throughout his publications, he insists that young earth creationists do real science, but even as he does so, he uses terms scientists simply don’t use. Ham uses the term “observational evidence” here because he wants to contrast what he argues is “real” science with what he claims is a separate, less reliably category of scientific research: “origins science” or “historical science.”
Ham's insistence that we cannot know past events because we “weren't there” ignores the vast amount of detective work that goes on every day to reconstruct past events in criminology, biology, genetics and may other fields.  He is the only one who believes this.

Tuesday, June 02, 2020

Homo erectus 200,000 Years Older Than We Thought

UPI has a story about a discovery in South Africa of a Homo erectus infant that is 200 ky older than the oldest known specimen currently in existence.  From the original Science article
Fossil hominins from South Africa are enriching the story of early human evolution and dispersal. Herries et al. describe the geological context and dating of the hominin-bearing infilled cave, or palaeocave, at a site called Drimolen in South Africa (see the Perspective by Antón). They focus on the age and context of a recently discovered Homo erectus sensu lato fossil and a Paranthropus robustus fossil, which they dated to ∼2.04 million to 1.95 million years ago. This makes Drimolen one of the best-dated sites in South Africa and establishes these fossils as the oldest definitive specimens of their respective species ever discovered. The age confirms that species of Australopithecus, Paranthropus, and early Homo overlapped in the karst of South Africa ∼2 million years ago
The goofy thing about this is that, in East Africa,  early Homo was still running around and out-competing the robust australopithecines (Paranthropus).  The fossil was uncovered and described over a five year period at the site of Drimolen, which is part of the UNESCO World Heritage Site in South Africa that contains the important fossil sites of Swartkrans and Sterkfontein. 

From the UPI story:
“One of the questions that interests us is what role changing habitats, resources, and the unique biological adaptations of early Homo erectus may have played in the eventual extinction of Australopithecus sediba in South Africa,” said study co-author Justin Adams, researcher at Monash University's Biomedicine Discovery Institute.
“Similar trends are also seen in other mammal species at this time. For example, there are more than one species of false sabre tooth cat, Dinofelis, at the site -- one of which became extinct after two million years,” Adams said. “Our data reinforces the fact that South Africa represented a truly unique mixture of evolutionary lineages -- a blended community of ancient and modern mammal species that was transitioning as climates and ecosystems changed.”
Just a few short years ago, it was thought that Australopithecus sediba might be ancestral to early Homo based on the characteristics of its hands, pelvis and the proximity of stone tools to the Rising Star Cave.  This was an idea championed by Lee Berger, but it now seems likely that it was another, earlier form that gave rise to Homo erectus

Here is the photo of DNH134, taken by Jesse Martin, Reanud Joannes-Boyau, and Andy I. R. Herries

Monday, June 01, 2020

Oldest Evidence of Siberian Crossing of Native Americans

UPI has a story about evidence from around Lake Baikal that links populations of Siberia to the earliest groups who came over from Siberia to the New World.  Brooks Hays writes:
New genomic analysis of ancient remains in Siberia -- detailed this week in the journal Cell -- have offered scientists fresh insights into the movements of human populations across Eurasia and into the Americas at the end of the Stone Age.

“Previous studies observed the genetic differences between individuals from different time periods, but didn't investigate the differences by dating the admixture events,” lead study author He Yu, postdoctoral researcher at the Max Planck Institute for the Science of Human History in Germany, told UPI in an email. “Our study reports a 14,000-year-old individual, which actually fills in a large blank of ancient genomes in this region, between 23,000 and approximately 8,000 years ago.”
By using the DNA of a tooth from the 14 ky old individual, Yu and his team have established links to the earliest Native Americans.
“The deep connection observed in this study is sharing of the same admixed ancestry between Upper Paleolithic Siberian and First Americans," Yu said. "We are not suggesting interbreeding between Native American and Siberian, or any back flow of Native American ancestry into Siberia. But we are suggesting that, the First American ancestry was formed in Siberia and also existed there, in a large range of time and space, so we can detect it in ancient Siberian individuals.”
There have always been conflicting theories about how and when the migrations to the New World occurred and there has always been evidence for movements from the Lena River, in Siberia and the northern Amur river in northern China.

Interestingly, they also found genetic evidence of the plague in some of the Bronze age populations from the area, which they hypothesized came from Europe, indicating that there was considerable movement between these populations.