Tuesday, January 15, 2019

The Brain of Little Foot

Science Daily had a story just a bit back about research done on the new information surrounding the Little Foot australopithecine remains from South Africa.  They write:
MicroCT scans of the Australopithecus fossil known as Little Foot shows that the brain of this ancient human relative was small and shows features that are similar to our own brain and others that are closer to our ancestor shared with living chimpanzees.

While the brain features structures similar to modern humans -- such as an asymmetrical structure and pattern of middle meningeal vessels -- some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.
One of the things that comes out in the paper is how much reorganization of the cranium we share with the higher primates, suggesting that quite a bit of brain evolution occurred prior to the Last common ancestor. The paper is currently free (at least I had no trouble accessing it) at http://dx.doi.org/10.1016/j.jhevol.2018.11.009. If not, the abstract is.

Friday, January 04, 2019

Creationism Linked to Conspiracy Theories?

In a remarkably ham-fisted article, Medical Xpress is peddling the notion that belief in creationism and conspiracy theories are linked.  They quote the authors of a study on the phenomenon thus:
“We find a previously unnoticed common thread between believing in creationism and believing in conspiracy theories,” says Sebastian Dieguez of the University of Fribourg. “Although very different at first glance, both these belief systems are associated with a single and powerful cognitive bias named teleological thinking, which entails the perception of final causes and overriding purpose in naturally occurring events and entities.”
This is a stretch. By their own admission, this is only modestly significant. The R2 for this model is 0.26, which means that only 26% of the model is explained by the variation.  Modest, indeed.  They continue:
“By drawing attention to the analogy between creationism and conspiracism, we hope to highlight one of the major flaws of conspiracy theories and therefore help people detect it, namely that they rely on teleological reasoning by ascribing a final cause and overriding purpose to world events,” Dieguez says. “We think the message that conspiracism is a type of creationism that deals with the social world can help clarify some of the most baffling features of our so-called 'post-truth era.'”
This is a completely reductive view of the world. It automatically assumes that there is no teleology to the world, that everything is chance and that there is no God. This is no better than when the Jesus Seminar started out with the assumption that none of Jesus' miracles could have been real.

My guess is that the a large percentage of the people that believe in conspiracy theories also believe in a whole host of other odd things, such as a flat earth.  I know quite a few young earth creationists and not a one of them subscribes to any conspiracy theories.  What drives their understanding of creation is a particular interpretation of the Bible.  Further, many of them are analytical thinkers.

More junk science.

Thursday, December 20, 2018

British Columbia Leading War in Canada against Creationism...Or Is It?

Support for young earth creationism is, apparently, somewhat variable when it comes to the different Canadian provinces.  This is not surprising, since one might reasonably same the same thing about the fifty United States.  Burnaby.com is reporting on efforts in British Columbia to assert control over this situation.  Mario Canseco writes:
There are many reasons for these regional variances. Over the past two decades, British Columbia has positioned itself as closest to secularism than any other region of Canada. Fewer British Columbians describe themselves as having “a religion” every time the census rolls around. Still, the last municipal election saw candidates running for school board seats – and winning – after outlining creationist views. Quebec has always been a land of contrasts when it comes to religion. The presence of a crucifix inside the National Assembly is debated extensively in a province where fewer residents are attending church services than ever before.
The odd thing here is that the writer of the piece has invoked a non-sequitur in the interpretation of the data, it seems.  He remarks that 55% of residents of BC would "keep creationism out of schools," but that conclusion doesn't follow from any of the graphs presented.  That is not the question asked.  The questions being asked are whether or not humans evolved or were created within the last 10,000 years.  While it is quite true that the two concepts are similar, one does not necessarily follow from the other.

Furthermore, it is not clear where he is getting his 55% number from, nor where he concludes that BC is leading the pack.  Eyeballing the graphs seems to indicate that BC is behind Alberta and Quebec in their acceptance of human evolution.

I am not sure I would put a lot of faith in this. 

Monday, December 10, 2018

Little Foot Finally Extricated

Nature News is reporting on the excavation and description of "Little Foot," a fossil initially discovered twenty years ago by Ron Clarke, at Sterkfontein Cave, in South Africa.  Colin Barras writes:
After a tortuous 20-year-long excavation, a mysterious ancient skeleton is starting to give up its secrets about human evolution.

The first of a raft of papers about ‘Little Foot’ suggests that the fossil is a female who showed some of the earliest signs of human-like bipedal walking around 3.67 million years ago. She may also belong to a distinct species that most researchers haven’t previously recognized.

“It’s almost a miracle it’s come out intact,” says Robin Crompton, a musculoskeletal biologist at the University of Liverpool, UK, who has collaborated with the research team that excavated the skeleton.
Why has this task taken so long and why is it so important? Barras continues:
By late last year, Clarke’s team had successfully removed enough bones to reconstruct more than 90% of the skeleton, and the specimen was unveiled to the world. No other Australopithecus fossil comes close to that level of completeness. For comparison, the most famous Australopithecus — Lucy — is around 40% complete.
Clarke and colleagues have posted a number of papers on the BiorXiv biology pre-print server. One of the papers is titled "The skull of StW 573, a 3.67 Ma Australopithecus skeleton from Sterkfontein Caves, South Africa."  Because these papers are unpublished, they are open-access. 

As Clarke and Kuman notes, this fossil is unlike those of Australopithecus africanus, a species ubiquitous in South Africa but more closely resembles, in some ways, Au. afarensis (Lucy) and Au. anamensis, both of which are north east African variants of Australopithecus and are the earliest members of that genus.  The fossil has been included, taxonomically, with a species originally described by Raymond Dart in 1948: Australopithecus prometheus.  Given its early date, the researchers argue that it cannot be descended from Au afarensis but must be coeval with it.  This suggests that both are descendants of an earlier species that had a large home range. 

More pieces to the puzzle. 

Tuesday, November 27, 2018

BioLogos: My Favorite Fossil

BioLogos is running a little series called "My Favorite Fossil."  Here is one by Ryan Bebej on Maiacetus inuus, a fossil whale.  I have also submitted one but it is currently being edited.  I will have another post when it is up. 

Monday, November 26, 2018

50th Anniversary of Epperson

The fiftieth anniversary of Susan Epperson's battle to overturn the Arkansas anti-evolution law came a few days ago.  Scientific American has a good recap written by Glenn Branch, as well as the current state of things.  In the post, Branch notes something that is often downplayed in a media circus dominated by personalities like Ken Ham:
And in a controversy dominated by a polarizing science-versus-religion stereotype, it is often insufficiently appreciated that a substantial portion of the faith community also supports the teaching of evolution. Entire denominations, such as the Episcopal Church, the United Methodist Church and the Presbyterian Church (USA), have issued statements affirming the compatibility of their faith and evolution, for example, while more than 16,000 individual clergy of the Christian, Jewish, Unitarian and Buddhist faiths have joined a grassroots effort to do the same.
As the professor says: read the whole thing.

Wednesday, October 24, 2018

Diane Douglas Unsuccessful at Limiting Evolution in Arizona Public Schools

Ars Technica is reporting that Diane Douglas, who had campaigned on editing the Arizona public school science standaards, has lost a primary race to another Republican challenger, scuttling her attempts.  John Timmer writes:
As we noted in our earlier coverage, Douglas has in the past suggested that schools teach intelligent design, which is the idea that life arose and diversified due to the intervention of an intelligent agent rather than evolution. It's an idea that was generated for religious purposes, and its teaching has been ruled an imposition of religion by the courts. She has also misunderstood the status of a scientific theory in suggesting that it reflected the idea that our knowledge of evolution is uncertain. These beliefs seem to have motivated her intervention into the science standards.

In September, however, Douglas' attempts to inject her beliefs into Arizona's classrooms ran into a couple of problems. To begin with, she faced a number of challengers during the Republican primary for her position; two of them received more votes than she did, meaning she won't have her party's nomination for re-election. Then, at a state school board meeting, the Arizona Science Teachers Association suggested a number of changes that restored details of climate change and evolution to the proposed standards.
Once again, I think that it is absolutely essential that people who are running for these positions should have to pass a basic test in scientific knowledge.  That is the only way to weed out the nonsense.


Hat Tip to Rob Mitchell.

Monday, October 15, 2018

Neandertal Teeth 450Ky Old Found in Italy

The Smithsonian is reporting that excavations in Italy have uncovered teeth dated to 450 thousand years ago that have Neandertal characteristics.
A fossil tooth study published today in the journal PLOS ONE analyzes some of the oldest human remains ever found on the Italian Peninsula. The teeth, which are some 450,000 years old, have some telltale features of the Neanderthal lineage of ancient humans. Dating back to the Middle Pleistocene, the fossils help to fill in gaps in an intriguingly complex part of the hominid family tree.

The species Homo neanderthalensis shares an unknown common ancestor with our own species, Homo sapiens, but it’s unclear exactly when the lineages diverged. Homo sapiens evolved perhaps 300,000 years ago, according to the fossil record, while Neanderthals’ evolutionary timeline has proven even trickier to pin down. Some genetic studies suggest that their lineage split from our own as long as 650,000 years ago, but the oldest definitive fossil evidence for Neanderthals extends back only about 400,000 years.
Conventional wisdom is that Neandertals emerged around 200 thousand years ago, in Europe. The Atapuerca Sima de Los Huesos remains, which show pre-Neandertal characteristics, are about the same age as the Italian remains. It has been suggested that Homo heidelbergensis is the common ancestor to both Neandertals and modern humans but this is far from clear. The genetics suggests that Neandertals and modern humans split around 600 thousand years ago but interacted as recently as 60 to 70 thousand years ago and interbred.Modern Europeans have between 3 and 6% Neandertal genes. 

This pushes back the origins of Neandertals and further muddies the picture of when and where these groups were and how they interacted.  More puzzle pieces. 

Saturday, September 22, 2018

Did the LCA Have Teeth More Like a Gorilla?

Artificial intelligence is playing a role in understanding human evolution.  From the Australian site News.com comes a story about new work in trying to understand what the last common ancestor to apes and humans might have looked like:
IT’S an image imprinted on our brains: the steady march of evolution from chimp to human. But it’s not quite right.

Monkeys don’t belong on the tree. They have tails.

Chimps, which don’t, are with Bonobos our closest living relatives. And, as such, both should be standing alongside us in the march of life.

Stretching out behind should be a gradually converging branch of earlier variations.

Ultimately, between six and eight million years ago, the branches almost certainly converge on one common ancestor.

We know almost nothing about what that was.
We have reasonably secure evidence of bipedality at around 6 million years in the form of Orrorin tugenensis from Kenya, as well as a crushed skull from Chad called Sahelanthropus that may or may not be 7 million years old, and recently, fossil footprints, purporting to show bipedal walking, from Crete have been uncovered that have been dated to around 5.7 million years ago.  Beyond that, nothing.  That is where the new AI study comes in.
The researchers used machine learning to teach an artificial intelligence to identify and classify fossilised hominid teeth dating from 25 million years ago. It then sifted through these to find patterns of development.

The study published in the science journal PaleoBios found one tantalising tip.

Our common ancestor almost certainly had gorilla-like teeth.

Now, it’s not a lot. And it certainly doesn’t say our ancestor was a gorilla.

But what it does do is add some shape and substance to this nebulous period of our human origins.
The information that is contained in the article is not nearly as cut and dried as is indicated by the news story. From the conclusion:
Given that the divergence of humans and chimpanzees occurred in the late Miocene, and that Miocene apes are much more similar to Gorilla in dental proportions, we assert that gorillas are the more appropriate extant model for the African ape LCA in terms of the relative sizes of the postcanine teeth. This similarity in dental proportions likely has implications for the interpretation of dietary adaptation and possibly phylogenetic relationships in Miocene apes, including the chimpanzee-human last common ancestor.
What this likely means is that, during the Miocene, which was the golden age of the apes, even after the divergence of Gorillas from the main line, there were extant forms that continued to have varying degrees of traits that could be associated with gorillas, presenting a classic case of collateral ancestry.  It is possible that one of the lines eventually led to chimpanzees, while another led to us.  We won't know more until we actually have some fossil remains from that missing time period. 
.

Friday, September 21, 2018

World's Oldest Animal Identified

A story in CNN (linked from elsewhere) reports that the world's oldest fossil has now been dated.  Rob Picheta writes:
The oldest known animal in the geological record has been identified, in a discovery that scientists are calling "the Holy Grail of palaeontology."
Fat molecules discovered on the fossil of a mysterious creature called Dickinsonia have confirmed that that it lived 558 million years ago, making it the earliest known member of the animal kingdom.
The findings place its existence 20 million years before the Cambrian Explosion event, when major animals began appearing on the fossil record.
The fossil was first discovered by Australian scientists on a remote Russian cliff face by the White Sea in 1947 and the study, published Friday, brings to an end a decades-long debate to identify what it was.
Here is an uncredited photo of the animal:

How do we know it had "fat" molecules? Apparently, it was so well preserved that it had traces of cholesterol.
"Scientists have been fighting for more than 75 years over what Dickinsonia and other bizarre fossils of the Ediacaran Biota were: giant single-celled amoeba, lichen, failed experiments of evolution or the earliest animals on Earth," Brocks said.
"The fossil fat now confirms Dickinsonia as the oldest known animal fossil."
Another piece of the puzzle.