Polar Bears Have The Luck Of The Irish

I recently learned that I share a trait with my absolute favorite animal, the polar bear, in that we can both trace our ancestry back to Ireland. For people who follow this blog, or have at least looked back through the archives a bit, you'll see that I find it impossible to pass up a good polar bear story. I've written about animal healthcare, mysterious death, and the polar bear's status (or lack thereof) as an endangered species. So it should come as no surprise that I can't pass up the opportunity to talk about this new research that shows an ancient Irish connection to modern day polar bears.

via Wikimedia Commons

A team of researchers led by Beth Shapiro of Penn State University and Daniel Bradley of Trinity College (Dublin) has identified a common ancestor of polar bears (Ursus maritimus) and brown bears  (Ursus arctos) that lived in Ireland before the peak of the last ice age some 20,000 to 50,000 years ago. The researchers concluded that all modern day polar bears can trace their lineage back to this ancient female brown bear. The specific lineage of the brown bear that shared their mitochondrial DNA with polar bears went extinct around 9,000 years ago, but the research still shows that the modern species are related.

Despite significant differences between polar bears and brown bears (size, coloring, fur type, tooth shape, swimming ability vs. climbing ability, etc.) scientists have suspected for some time that the species have closely connected histories. The polar bear is known to have mitochondrial DNA (the part of the genome contributed by the mother) that traces back to the brown bear. But how modern polar bears acquired this brown bear DNA was a bit of a mystery.

via Wikimedia Commons

The two species are known to interbreed, and have been studied in captivity in addition to being spotted in the wild. An example of a polar bear/brown bear hybrid, jokingly nicknamed grolar bear or pizzly, was found in the wild Canada in 2006. But, even with the knowledge that the two species can co-mingle scientists were still perplexed about the history of these different species. The long standing theory about how polar bears evolved from brown bears had their history traced to the ABC Islands (the Alaskan Islands of Admiralty, Baranof, and Chichagof) around 14,000 years ago. But the bears' genomes tell us a different story.

The research team led by Shapiro and Bradley found that the hybridization of polar bears occurred much earlier than would have been possible on the ABC Islands through a genetic analysis of the bears. The study analyzed 242 samples from polar bear and brown bear mitochondrial DNA spanning 120,000 years and several different geographical regions. The researchers found that the fixation of the mitochondrial genome in polar bears likely occurred closer to 50,000 years ago in the area of present-day Ireland.

According to Shapiro, in addition to genetic evidence, the interconnected history of the polar bear and brown bear is also supported by climate events. One example of this is the British-Irish ice sheet, which reached its maximum range around 20,000 years ago. At this time parts of Ireland would have been difficult to inhabit, pushing bears from the warmer areas toward ice shelves and land exposed by lower sea levels. This would have brought the bears into close contact with their northern neighbors, showing how the animals that became two different bear species could have started out in the similar location, sharing their genes.

The polar bear is currently considered a threatened species, and future conservation efforts may be aided by this new understanding of its genetic history and its ability to hybridize with the brown bear. The research is described in the paper, "Ancient Hybridization and an Irish Origin for the Modern Polar Bear Matriline" in the journal Current Biology.

Violence & Forced Silence in the Evolution vs. Creation Controversy

I'm going to try not to launch into a personal diatribe about why religion and evolution don't have to be mutually exclusive, but please note this post is entirely my opinion - an editorial if you will.

It seriously burns me that so many people insist that the issue of human origin has to be black and white either all science or all religion, completely overlooking the grey area where science and religion could meet if we were willing to see things in a new way. I bring up this up, despite it being undoubtedly controversial, because of this: Imam who believes in evolution retracts statements. Dr. Usama Hasan, a lecturer at Middlesex University in the UK and an Imam at Leyton Mosque in east London has retracted statements in favor of evolution after receiving death threats.

I'm not criticizing Dr. Hasan for saying he thinks he went too far and retracting the statements. But I am criticizing the fact that he was put in the position where he felt he had to. People should be able to disagree about ANY issue, let alone their personally held (even when publicly expressed) religious beliefs without fearing for their life.

According to the BBC's article on the retraction, Dr. Hasan originally made the comments in 2008, but in January 2011 received death threats following a lecture where he re-iterated the ideas. The original opinion piece by Dr. Hasan, which appeared in the Guardian Newspaper, stated that Muslims are in need of an open discourse about creationism and evolution because science can neither prove or disprove the existence of God. This is an argument that is true for any religion, and honestly not one that I find all that extreme. He's just saying we should talk about it.

The following video is of Dr. Hasan trying to explain his beliefs on evolution to a group that heckles him from the start. What strikes me most is when he says to the audience, "disagree if you wish, but please read," he encourages them to learn basic science and gets verbally berated for it.

In the Guardian article Dr. Hasan also says, "One problem is that many Muslims retain the simple picture that God created Adam from clay, much as a potter makes a statue, and then breathed into the lifeless statue and lo! it became a living human. This is a children's madrasa-level understanding and Muslims really have to move on as adults and intellectuals."

Now, I get why he pissed people off with the above statement. No one wants to be called a child for believing as they do. It is incendiary, more incendiary than some of his other claims in favor of evolution. He poked the proverbial sleeping bear with this one. But that doesn't mean the people he offended should be allowed to threaten his life, or should even feel it is their right in the first place to tell him that he deserves to die for his ideas. No one has that right.

As a society we have determined that it is not okay to just kill anyone who doesn't agree with you. Death threats and intimidation are illegal, religiously grounded or otherwise. I think it is honestly a tragedy for society that someone who encourages a peaceful meeting place between science and religion has been in a way silenced by fear.

If we don't question religion, how can we be sure that it is really what we believe? I don't think that blindly following the interpretations of religious texts is the best way to guide your actions through life. Think about your religion. Think about what the texts say. Think about the world in which you live, and what you know to be true about it. Look at the scientific evidence. Give it due consideration. Form an opinion based on all of that, and allow others to disagree with you. If someone wants to believe that science is itself the work of God, let them. It doesn't hurt you, or diminish what you believe.

If we can not express our beliefs, even when critical of the beliefs held by others, then society is not free. Why can't we all just get along, really? Having differing opinions on the origin of humans doesn't hurt anyone socially, economically or otherwise. As a society we COULD just agree to disagree on this issue. But I have no misguided hopes that we someday will.

For a full disclosure of where my personal bias stands on this issue, I identify my own beliefs with the following thinking: "That which is impenetrable to us really exists. Behind the secrets of nature remains something subtle, intangible, inexplicable. Veneration for this force beyond anything we can comprehend is my religion" and "Science without religion is lame. Religion without science is blind." -  both are Albert Einstein.  And for good measure: "There is not a righteous man on Earth who does what is right and never sins" - Ecclesiastes 7:20. No one is right all the time. To think so is in itself to challenge religion (at least in this example, Christianity - to which I most closely identify of all the organized religions.)

If EVERYONE whether you believe in Evolution, Creation or something in between could come down off their soap box to admit that maybe the opposing view isn't pure hooey, wouldn't we all be better off? You don't have to sell out your own beliefs or give up on them to admit that another way of thinking might be possible. If only we could all be so highly evolved as to do so....

Fossil Foot Shows Bipedalism

I recently did a post on the taxonomy of the African Wolf, (formally the Golden Jackal) where I talked about how as scientists gather more information and make new discoveries, they revise their theories. There is an interesting article in the BBC today about a new fossil find that has helped scientists fine-tune their theories about how the human-like species Australopithecus afarensis moved. This fossil is a great example of scientists learning from new discoveries.

A. afarensis is the species made famous by the "Lucy" skeleton discovered by Donald Johanson in 1974 in the Hadar region of Ethiopia. Previously, researchers had fossilized remains of the spine, hips, and knees of A. afarensis and developed a theory about how the species moved based on those fossilized remains. Researchers believed that A. afarensis was bipedial (walked upright on two feet, like humans).

Until recently the theory that A. afarensis was bipedal lacked certainty because while researchers were confident that the spine, hips, and knees supported the bipedal theory, A. afarensis foot bones had never been found. Without the foot bones, the researchers could not confirm just how the species walked, or how much it relied on walking.

Source: Anthropology.net

Now a research team from Arizona State University (including Donald Johanson) has found a fossilized fourth metatarsal bone from A. afarensis, in the same Hadar region of Ethiopia where the Lucy skeleton was found. The metatarsal is a foot bone that provides evidence of how the foot was arched. Understanding how the foot was arched goes a long way to explaining how the creatures would have walked, confirming the researchers long-standing bipedal theory.

In addition to supporting the bipedal theory, the foot bone and the fact that it is arched shows that A. afarensis would have been able to move quickly and easily on two feet. The arches in feet serve to help the foot move the body forward, and act as a "shock absorber" each time the feet pound the ground. The fact that A. afarensis had arched feet makes it even more similar to the anatomy of modern humans showing an important link in the evolution of upright walking.

I think this is such a great example of how science changes and revises itself because it showcases how very specific details and pieces of information can shape entire theories. In this case, finding the fossilized metatarsal bone confirmed a theory and also shed more light on how the species would have walked, providing additional information. It is a good example of science changing - and getting better.