{"id":259747,"date":"2023-05-30T19:23:23","date_gmt":"2023-05-30T17:23:23","guid":{"rendered":"https:\/\/climatescience.press\/?p=259747"},"modified":"2023-05-30T19:23:26","modified_gmt":"2023-05-30T17:23:26","slug":"the-story-of-polar-bear-evolution-could-not-be-told-without-discussing-climate-change","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=259747","title":{"rendered":"The story of polar bear evolution could not be told without discussing climate change"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

From polarbearscience<\/a><\/p>\n\n\n\n

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\u00a0how evolution works<\/a>\u00a0but perhaps not quite how you imagined it.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

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 interglacials. MIS 2 was the Last Glacial Maximum.<\/p>\n\n\n\n

But where and when during this period of change did polar bears come to be\u2013and 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).<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Polar Bear Evolution: A Model for How New Species Arise <\/em>explains when and where<\/em> the species came to be, as well as how <\/em>it happened and why<\/em> they were able to survive repeated cycles of sea ice change, some of unimaginable magnitude.<\/p>\n\n\n\n

Here you\u2019ll find a detailed account of fossil evidence, recent hybridization<\/a> events between brown bears and polar bears, and summaries of more than a dozen genetic studies that have been done on these bears to determine the most plausible time and place for the origin of polar bears.<\/p>\n\n\n\n

It\u2019s logical to assume this speciation event happened during a cold interglacial, but which one?<\/p>\n\n\n\n

And if you\u2019ve ever wondered whether polar bears could have arisen more than once or if hybridization with brown bears<\/a> really did play a significant part in polar bear evolution\u2013as some geneticists insist<\/a>\u2013this book is for you.<\/p>\n\n\n\n

Unique to this account, a biological mechanism reveals how this rapid transformation from a brown bear ancestor could have happened.<\/p>\n\n\n\n

Thyroid hormone, essential for countless coordinated body functions including stress responses, the growth of embryos, and the activation of critical genes, seems to have played a vital role in the vast majority of all\u00a0rapid speciation events<\/a>.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

A testable theory based on thyroid hormone not only explains how polar bears came to be but does the same for domestic dogs<\/a>, flightless birds like the dod<\/a>o, and extinct dwarf proto-human from Indonesia known as \u201cHobbits.<\/a>\u201d<\/p>\n\n\n\n

This evolutionary history of the polar bear also explains why the modern species is essentially pre-adapted to persist in a warmer world<\/a>.<\/p>\n\n\n\n

Whenever the species first arose, its survival through the very warm early Eemian interglacial<\/a>, an extended period of about ten thousand years (at ca. 130-120k years ago), when there was consistently much less summer and winter sea ice than today, ensured the polar bear was forever flexible enough to deal with profound variations in sea ice. <\/p>\n\n\n\n

Or did lack of sea ice cause it to go extinct and arise a second time?<\/p>\n\n\n\n

It\u2019s a fabulous story\u2013you\u2019re going to love it.\u00a0\u00a0<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

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\u00a0how evolution works\u00a0but perhaps not quite how you imagined it.<\/p>\n","protected":false},"author":121246920,"featured_media":259758,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_crdt_document":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691819822,691819823,691818251],"class_list":{"0":"post-259747","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","6":"hentry","7":"category-uncategorized","8":"tag-brown-bears","9":"tag-last-glacial-maximum","10":"tag-polar-bears","12":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=2455%2C1929&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-15zt","jetpack-related-posts":[{"id":287347,"url":"https:\/\/climatescience.press\/?p=287347","url_meta":{"origin":259747,"position":0},"title":"Polar Bear Evolution pre-Christmas book sale: discounts on all formats!","author":"uwe.roland.gross","date":"09\/11\/2023","format":false,"excerpt":"This fascinating story finally brings together everything that scientists have learned about the origin of polar bears, in clear language that non-scientists will understand: not just\u00a0when and where\u00a0the species arose, but exactly\u00a0how\u00a0it happened and why the bears were able to survive repeated cycles of sea ice change, some of unimaginable\u2026","rel":"","context":"In \"book\"","block_context":{"text":"book","link":"https:\/\/climatescience.press\/?tag=book"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":264124,"url":"https:\/\/climatescience.press\/?p=264124","url_meta":{"origin":259747,"position":1},"title":"No evidence polar bears survived Eemian warmth because they were not yet fully ice-dependent","author":"uwe.roland.gross","date":"27\/06\/2023","format":false,"excerpt":"Is evolution primarily fast or slow? Does it take hundreds of thousands of years or a few\u00a0generations\u00a0to produce a new species? Ignoring\u00a0vast evidence\u00a0to the contrary, most geneticists insist that evolutionary change is imperceptibly slow and\u00a0one of them\u00a0is using this misconception to support the human-caused climate change narrative.","rel":"","context":"In \"Arctic sea ice\"","block_context":{"text":"Arctic sea ice","link":"https:\/\/climatescience.press\/?tag=arctic-sea-ice"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":261713,"url":"https:\/\/climatescience.press\/?p=261713","url_meta":{"origin":259747,"position":2},"title":"How grizzlies evolved into polar bears: The first book to tell the whole story is now available","author":"uwe.roland.gross","date":"12\/06\/2023","format":false,"excerpt":"Polar Bear Evolution: A Model for How New Species Arise\u00a0is the fascinating story of the origin of polar bears. It reveals not just\u00a0when and where\u00a0the species came to be, but\u00a0how\u00a0it happened and\u00a0why\u00a0the bears were able to survive repeated cycles of sea ice change, some of unimaginable severity.","rel":"","context":"In \"Grizzlies\"","block_context":{"text":"Grizzlies","link":"https:\/\/climatescience.press\/?tag=grizzlies"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":243906,"url":"https:\/\/climatescience.press\/?p=243906","url_meta":{"origin":259747,"position":3},"title":"Polar bear evolution book is progressing well","author":"uwe.roland.gross","date":"09\/02\/2023","format":false,"excerpt":"In the early 1960s paleontologist Bjorn Kurt\u00e9n 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.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-348.png?fit=1200%2C790&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-348.png?fit=1200%2C790&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-348.png?fit=1200%2C790&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-348.png?fit=1200%2C790&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-348.png?fit=1200%2C790&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":263983,"url":"https:\/\/climatescience.press\/?p=263983","url_meta":{"origin":259747,"position":4},"title":"Claims of interspecies hanky-panky have unfairly sullied polar bear & Neanderthal reputations","author":"uwe.roland.gross","date":"26\/06\/2023","format":false,"excerpt":"One big question I asked before writing my book on\u00a0polar bear evolution\u00a0was this: did interbreeding with grizzlies, aka\u00a0brown bears, profoundly impact polar bear history, as geneticists insist? Or is something else going on?","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":367834,"url":"https:\/\/climatescience.press\/?p=367834","url_meta":{"origin":259747,"position":5},"title":"No News is Good News on Polar Bear Day: Celebrate With 35% Off Polar Bear\u00a0Evolution","author":"uwe.roland.gross","date":"27\/02\/2025","format":false,"excerpt":"Instead of asking whether polar bears will survive a bit of warming over the next few decades, ask yourself how they survived more than 100,000 years of unimaginable changes in Arctic climate (both much warmer\u00a0and\u00a0colder) before now?","rel":"","context":"In \"Arctic Climate\"","block_context":{"text":"Arctic Climate","link":"https:\/\/climatescience.press\/?tag=arctic-climate"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=1050%2C600 3x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/259747","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=259747"}],"version-history":[{"count":6,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/259747\/revisions"}],"predecessor-version":[{"id":259759,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/259747\/revisions\/259759"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/259758"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=259747"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=259747"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=259747"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}