Monday, November 28, 2016

How Will Climate Change Affect Human Evolution?

Gizmodo asked a number of scholars how they thought AGW will affect human evolution.  Some of the answers were interesting. Biological anthropologist John Hawks wrote:
I’ll be honest — the degree of climate change we are talking about in the next couple of centuries, which is on the order of several degrees Celsius, is by and large going to make the temperate regions of the world more similar in temperature to tropical Africa, where all our ancestors originated. We’re effectively terraforming the world to be more like our origins. The effects on humans are much more social and economic than evolutionary.

To the extent we see evolution, it will be changes in plant and animal species. Some will change the timing of their lives, some will invade new areas where they couldn’t adapt before, and many will become extinct — especially those today locked into small “reserves” that will undergo local climate shifts faster than they can adapt. And of course we will exert our own selection and genetic engineering upon our crops and domesticated animals to suit the changing climate.
Biological anthropologist Chris Stringer wrote:
The pace of change is likely to be too fast and dramatic for us to evolve physically to meet the challenges of a much warmer world. Any changes would have to come from cultural or social accommodation to the new situations – if that proves possible.
I think it is still way to early to tell how the earth will respond to anthropogenic changes in climate. If you will recall, only fifteen years ago, people were talking about global cooling.

Monday, November 14, 2016

...And About Creationism Going Extinct in Texas...

Raw Story has a postmortem on the 2016 presidential election and focuses on Texas races that went very badly for Democrats.  Kaiah Collier writes:
Republicans seeking re-election to the State Board of Education managed to hang onto their seats Tuesday despite speculation that the unpopularity of the candidate headlining the GOP ticket, Donald Trump, may flip certain races. And one newcomer seeking an open seat in a deeply conservative East Texas district easily bested his Democratic rival.
So, what effect will this have on the teaching of evolution?
The GOP’s good showing Tuesday is a win for conservative members of the state board who are mounting a fight to keep creationism in Texas’ science curriculum standards. Determining the big topics teachers must impart on the state’s more than 5 million schoolchildren is one of the board’s biggest duties, along with approving textbooks.
Let the skirmishes begin.

Friday, November 11, 2016

New Study on Homo naledi

Lauren Schroeder and colleagues have published a report on the skull of Homo naledi, in which they address the characteristics and attempt to place them in a taxonomic context, using morphometric analysis.  From the abstract:
Our results indicate that, cranially, H. naledi aligns with members of the genus Homo, with closest affiliations to H. erectus. The mandibular results are less clear; H. naledi closely associates with a number of taxa, including some australopiths. However, results also show that although H. naledi shares similarities with H. erectus, some distances from this taxon – especially small-brained members of this taxon – are extreme. The neighbor joining trees place H. naledi firmly within Homo. The trees based on cranial morphology again indicate a close relationship between H. naledi and H. erectus, whereas the mandibular tree places H. naledi closer to basal Homo, suggesting a deeper antiquity. Altogether, these results emphasize the unique combination of features (H. erectus-like cranium, less derived mandible) defining H. naledi. Our results also highlight the variability within Homo, calling for a greater focus on the cause of this variability, and emphasizing the importance of using the total morphological package for species diagnoses.
Another major finding of the study is that a grouping of H. naledi and specimens of Homo erectus "exceeds, in many instances, what we would expect if this grouping represented a single species."  Recall that we have zero idea how old this find is and, to the extent that this is possible, are trying to place this skull using only taxonomic analysis. Nonetheless, it gives us more information about this stage of hominin evolution and suggests that there was considerable variation of morphs running around during the transition from the australopithecines to early Homo

Wednesday, November 09, 2016

Richard Dawkins Parody

Warning: this one is a bit off-color but quite funny nonetheless.  Recall, in recent years, the low-level animosity that has been leveled at Starbucks for not having a Christmas-themed coffee cup.  Well, some enterprising soul put up a wicked parody of this with Richard Dawkins on the front of a Dunkin' Donuts cup.  I won't reproduce the image here, this being a family site and all, but I will add the description from the original Above Average site (warning: crude description):
When I stopped into Dunkin Donuts yesterday, I was greeted by a terrible surprise when the cashier handed me my hot chocolate in their new holiday cup. There was no Christmas motif, no red and green, and not a seasonal snowflake to be found. It was just the Dunkin Donuts logo and a picture of notorious atheist Richard Dawkins giving me the finger. I asked to speak to the manager immediately.

“This is outrageous!” I yelled at her. “How could you make such a horrible cup?!”

“I don’t know, I don’t make the cup designs,” she replied sheepishly. “They were just trying to be inclusive I guess? I honestly don’t even know who that is.”
Apparently, quite a few people didn't recognize the parody for what it was and Bookface lit up like a Christmas Tree with complaints about Dunkin' Donuts (which they probably didn't appreciate one bit). The parody showed up on Snopes pretty quickly, who had this to say:
This article was just a satirical take on the annual "War on Christmas" controversies that have in recent years included Starbucks' holiday cups, including the 2015 version that did not feature any religious symbols, as well as the coffee chain's November 2016 (non-holiday) green unity cup.

Tuesday, November 08, 2016

What Our Ancestors Ate

NPR has a story on dietary analysis of fossilized hominin teeth called Dental Detectives.  Erin Ross writes:
When scientists want to know what our ancient ancestors ate, they can look at a few things: fossilized animal bones with marks from tools used to butcher and cut them; fossilized poop; and teeth. The first two can tell us a lot, but they're hard to come by in the fossil record. Thankfully, there are a lot of teeth to fill in the gaps.

"They preserve really well," explains Debbie Guatelli-Steinberg, a dental anthropologist at Ohio State University. "It's kind of convenient because teeth hold so much information."

The structure of a tooth and even the amount of enamel, for example, hint at what the teeth are adapted to eat.
Peter Ungar, of the University of Arkansas, adds this:
“If you eat Jell-O almost every day of the year, but sometimes you need to eat rocks ... you want teeth that can eat rocks,” he explains. So, teeth are usually adapted for the toughest component of an animal's diet, not what it eats on a daily basis.

To see what an animal was actually eating, Ungar studies something called dental microwear, the marks left behind by food on teeth. As we chew on say, a celery stick, hard particles — either bits of silica from the plants' cells or sand and grit from the surrounding environment — are dragged across and pressed into our teeth.
Beyond this, though, detailed isotope analysis of teeth has revealed changes in migration and patterns: Ross writes:
Teeth from more recent fossils reveal more because they have more isotopes preserved in them. For example, the nitrogen in the teeth of Neanderthals can reveal whether the protein they ate came from plants or animals. It's one of many reasons researchers think Neanderthals hunted large mammals, though scientists have also found fossilized plants stuck in Neanderthal teeth.

Researchers were even able to use isotopes to find out when one Neanderthal started weaning her baby. As teeth grow, they lay down layers of enamel. And barium, a molecule children get from breast feeding mothers, builds up in baby teeth until the mother stops nursing. By comparing barium in a Neanderthal tooth with levels in donated present day baby teeth, the scientists were able to find out that the Neanderthal baby had been weaned at about seven months.
More pieces to the puzzle. Read the whole thing.

Monday, November 07, 2016

Oh Ye of Great Faith!

Zack Kopplin writes in the Daily Beast that creationism could go extinct in Texas with this election cycle.  Oh Ye of Great Faith!  To wit: 
Teaching creationism in Texas public schools may become illegal next year.

In September, a group of educators chosen by the Texas Education Agency to streamline the state’s science curriculum standards removed portions of four passages that contained creationist language. The new standards must still be approved by the Texas State Board of Education where creationists are fighting to reverse the changes. The board members, unlike the education agency staff, are elected officials. That means the fate of creationism in Texas could be determined on Election Day.

If the decision stands, it would be a major blow to political creationism and the first time in a decade for any state’s creationism policy to be overturned.
Texas has always been a battleground state for evolution, but great strides have been made in recent years, first with the ousting of Don McLeroy, a strident creationist who famously said “I disagree with these experts. Someone has got to stand up to experts.”  McLeroy, if you will recall, was a dentist.  Kopplin is, in my view, being overly optimistic.  They will never go gently into that good night.  They will rage, rage, against the dying of the light (apologies to Dylan Thomas).  He continues:
The final vote on the new standards will take place next spring and control of the 15 member board is narrowly split 6-6 between moderates and religious conservatives, with 3 more Republican board members acting as swing voters. If the vote were held today, it’s probable the new standards would be approved. But after the election, the vote becomes less clear.
Creationism tends to reappear in continuous fashion, because so much of the populace supports it and the legislators (many of whom have sympathies in this direction) fell compelled to support their constituencies. If the standards get voted out this election cycle, they will be back for the next one.