Posted onJune 26, 2023|Comments Off on No evidence polar bears survived Eemian warmth because they were not yet fully ice-dependent
Is evolution primarily fast or slow? Does it take hundreds of thousands of years or a few generations to produce a new species? Ignoring vast evidence to the contrary, most geneticists insist that evolutionary change is imperceptibly slow and one of them is using this misconception to support the human-caused climate change narrative.
For polar bears, the question is this: could brown bears (aka grizzlies) have survived for hundreds of thousands of years living in a completely different habitat–the perpetually-frozen world of Arctic sea ice–before significant biological changes took place? I contend the answer is no. Moreover, if I am correct that polar bears arose ca. 140,000 thousand years ago (140kya) during the height of an extreme glacial period, the fossil evidence concurs. Analysis of fossil remains show that by about 115-130kya at the latest (after perhaps 10k years), polar bears were primarily eating seals as their modern counterparts do and their bones had lost the distinctive features of their grizzly ancestors.
But that’s the maximum time frame: research on other animals indicate that such critical changes almost certainly took place long before that, within the first few generations of life on the sea ice. If coordinated changes had not taken place very quickly, within ecological time, brown bears would simply not have survived the harsh life on Arctic sea ice.
Posted onJune 11, 2023|Comments Off on How grizzlies evolved into polar bears: The first book to tell the whole story is now available
Polar Bear Evolution: A Model for How New Species Ariseis the fascinating story of the origin of polar bears. It reveals not just when and where the species came to be, but how it happened and why the bears were able to survive repeated cycles of sea ice change, some of unimaginable severity.
No other book like this exists. Despite decades of serving as an icon for the catastrophic climate change narrative, the polar bear has never had its evolutionary history explained so completely, never mind in a fully-referenced, plain-language style. And I couldn’t have done it without the financial help of my many supporters, so I thank you all again for your assistance in getting this important work completed.
The author of Polar Bear Evolution, Susan Crockford, is a good, credentialed scientist. Her writing is clear; her thinking is also. She has a broad understanding of biology and an informed paleo perspective. Crockford condenses a very large literature on polar bear biology and evolution in this book which will help readers understand the science related to the evolution of an Arctic species. Perhaps the most important aspect of this book is its synthesis of information from the fields of wildlife biology, molecular evolution, paleontology, and climate. Her original ideas and hypotheses on thyroid hormone’s role in evolution are very important and add a credible mechanism of phenotypic change which complements the literature on molecular genetic evolution. Polar Bear Evolution is an important contribution to science and its application in evolutionary biology and wildlife biology. Matthew A. Cronin, Ph.D.
Posted onJune 2, 2023|Comments Off on Grizzlies vs. grizzly X polar bear hybrids by appearance alone: a photo essay
Hybridization with grizzlies comes up repeatedly in genetic studies that aim to zero in on polar bear origins and is one of the issues I explore in detail in my upcoming new book, Polar Bear Evolution: A Model for How New Species Arise. Here is a photo essay to get you thinking about grizzly X polar bear hybrids, because understanding the topic is critical to unravelling the genetic evidence on how polar bears came to be.
For example, who can forget the hoopla over the bear shot near Arviat on the shore of Western Hudson Bay in 2016 (shown above) that everyone, including polar bear expert Ian Stirling, decided must be a hybrid–but it turned out to be a blonde grizzly.
Explaining all the ins and outs of why hybrids are important to polar bear evolution is an important part of my book.
Posted onMay 30, 2023|Comments Off on The story of polar bear evolution could not be told without discussing climate change
Polar bears arose as a new species because the climate changed and forced some brown bears to colonize the sea ice. Polar bears epitomize the story of how evolution works but perhaps not quite how you imagined it.
Moving from extremes in warmth to extremes in cold characterized the last million years of geological history, as the graph above shows, where odd-numbered Marine Isotope Stages (MIS) are warm interglacials and even-numbered stages along the bottom are cold glacials. MIS 2 was the Last Glacial Maximum.
But where and when during this period of change did polar bears come to be–and how, exactly, did it happen? My new book tells the whole story, which has never been done before. Not long to wait now, the release date is only about a week away (1st week June).
Posted onFebruary 8, 2023|Comments Off on Polar bear evolution book is progressing well
Just a short update regarding progress on the book. I am deciding on a cover design while addressing suggested changes as they come back from the editor, and preparing marketing material. If all goes to plan, I am on track for a March publication date–thanks to your support.
In the early 1960s paleontologist Bjorn Kurtén thought that polar bears likely arose from a brown bear ancestor based on fossil evidence alone, and his estimate of when this happened was determined by the age of fossil remains of both species. As I will show in the chapters that follow, despite more fossil evidence being available and additional evidence from molecular genetic studies, his estimate is still the most likely time frame for when the polar bear came to be.
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Posted onJuly 4, 2022|Comments Off on Polar bear evolution and recent genetic papers
Two scientific papers in June on polar bear evolution got a bit of media attention but not what the topic deserves. I’ve not written about them because I am currently working on a larger piece putting this conflicting genetic information into full context. Have patience, it’s coming.
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Posted onMarch 2, 2021|Comments Off on Podcast with WildFed about polar bears and domestication as speciation
A couple weeks ago I had a fabulous chat with Daniel Vitalis from Wildfed about a wide range of topics, including my work on polar bears and domestication as a process of speciation. The podcast went live this morning – have a listen here (also copied below), I think you’ll enjoy it. One hour, 36 minutes.
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Posted onMay 10, 2014|Comments Off on Evolution by geneticists again: yet another date for when polar bears arose
The latest addition to the never-ending story of when-and-why polar bear evolution took place according to geneticists (Liu et al. 2014 — the 8th such paper in less than 4 years, if you can believe it) is getting way, way more media attention than it deserves.
Liu et al. 2014 figure provided in the abstract.
This multi-member research team used a new data set (mostly Scandinavian brown bears and Greenland polar bears, for a change) to add not much of anything new on the evolutionary insight front except yet another estimate of when polar bears came to be.1
However, the real focus of the paper is the description of their finding of a few genetic differences between brown bears and polar bears that they identified. They found a few genes in polar bears were different than brown bears and made a boat load of assumptions about what these might mean.
Their discovery was not accompanied by any attempt to demonstrate that the changes in gene architecture they found also involved a change in the function of the genes or were associated with different effects on bear physiology. If a changed gene cannot be shown to act differently or to have a demonstrated new physiological effect on the animal in question, the changes themselves mean next to nothing – especially for evolution!
That’s my take – see what you think. It looks long but a lot of it is quotes. Continue reading
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