Episode 306: Two Million Years Ago in Greenland
b"This week we're going to learn about a brand new study in\\xa0Nature about animals and plants that lived in Greenland about two million years ago.\\n\\nHappy birthday to Dillon!\\n\\nFurther reading:\\n\\nA 2-million-year-old ecosystem in Greenland uncovered by environmental DNA\\n\\nScientists Reconstruct 2-Million-Year-Old Ecosystem from Environmental DNA\\n\\nNo bones? No problem: DNA left in cave soils can reveal ancient human occupants\\n\\nGreenland now:\\n\\n\\n\\nGreenland two million years ago [art by Beth Zaiken, taken from the second article linked above]:\\n\\n\\n\\nShow transcript:\\nWelcome to Strange Animals Podcast. I\\u2019m your host, Kate Shaw.\\nThis week we\\u2019re going to do something a little different and talk about a new study just published in the journal Nature. A little section of this episode is taken from a recent Patreon episode, for those of you who listen and think, \\u201cWait, I\\u2019m pretty sure I\\u2019ve heard that before.\\u201d\\nBefore we get started, though, we have a birthday shoutout! A great big happy birthday to Dillon! I hope you do something really silly and fun on your birthday, like dance around wearing a ridiculous party hat and then eat cake.\\nGreenland is a big island off the eastern coast of Canada, but way far north, more or less in the Arctic. Even though it\\u2019s off the coast of North America, it\\u2019s considered part of Europe because for the last thousand years, it\\u2019s been controlled by Norway or Denmark at various times. Denmark\\u2019s got it right now. A little over 56,000 people live there today, most of them Inuit.\\nA big part of Greenland is covered in an ice sheet over a mile thick, which is so heavy it has pushed the central section of the island down so that it\\u2019s almost a thousand feet, or over 300 meters, below sea level. The land is much higher around the edges of the country. Basically Greenland is a gigantic bowl full of ice.\\nIn 1966, the U.S. Army drilled into the ice to see what was under it, and the answer is dirt, as you might have expected. They took a 15-foot, or 4.5 meter, core sample and stuck it in a freezer, where everyone promptly forgot about it for 51 years. At some point it ended up in Denmark, where someone noticed it in 2017.\\nIn 2019, the frozen core sample was finally studied by scientists. They expected to find mostly sand and rock. Instead, it was full of beautifully fossilized leaves and other plant material.\\nThe main reason scientists were so surprised to find leaves and soil instead of just rock is that ice is really heavy, and it moves\\u2014slowly, but a mile-thick sheet of ice cannot be stopped. If you remember episode 277 about the rewilding of Scotland, you may remember that Scotland doesn\\u2019t have a lot of fossils from the Pleistocene because it was covered in glaciers that scoured the soil and everything in it down to bedrock, destroying everything in its path. But this hasn\\u2019t happened in Greenland.\\nWhere the ice sheet now is, there used to be a forest. Obviously, the ice sheet hasn\\u2019t always covered Greenland. Research is ongoing, but a study of the sediment published in 2021 indicates that Greenland was ice free within the last million years, and possibly as recently as a few hundred thousand years.\\nIf you go back a little farther, around two million years ago, Greenland was radically different. Not only was it ice free, it was much warmer than it is today. In north Greenland, which is now a polar desert, there was once an open forest where an incredible number of plants and animals lived. We know because of environmental DNA sequencing, often referred to as eDNA.\\nAt this point most of us have a good understanding of what DNA is, but I\\u2019ll give you a quick explanation in case you\\u2019re not sure. DNA stands for Deoxyribonucleic acid, and it\\u2019s a polymer chain found in every organism\\u2019s cells that contains genetic instructions, essentially a guide on how to grow a particular type of animal. It\\u2019s way more complicated than that, but that gives you a basic idea. When cells replicate as an organism develops,"