Hello and welcome back to extinctions where 99 percent of all species are dead and the rest are on their way. Anyway, let's think about when human concepts of extinctions may have started. We could just jump to the science of the past few centuries in which mostly European and American scientists began pondering fossils and their meaning, and how these fit into the history of life. We will do that, but just not yet. Humans have used science as a way to understand the world around us since our beginning as a species. For instance, our ancestors successfully identified plants that were edible or medicinal and avoided ones that were inedible or toxic. They identified and hunted animals by tracking them and interpreting their behaviors from tracks and sign. They also observed weather and seasonal cycles, which helped them considerably with hunting, gathering, and agriculture. They also developed navigation methods on land and sea through applied astronomy. All of these forms of knowledge contributed to our survival as a species, meaning that we're here now because of sciences used throughout our history. So considering all of this necessary awareness of the natural world, it only makes sense that indigenous peoples would have recognized fossils as the remains of once living organisms. Furthermore, they would have also realized that no living examples of these fossil plants or animals were still around, implying that they belong to a past time, perhaps even before people started living in these places. Sure enough, we have plenty of evidence of this fossil awareness through native peoples legends. Of course, legends are stories, and stories don't necessarily have to be true, like legends of the fall. But legends inspired by real fossils and especially those created in societies that dependent more on oral traditions rather than written ones, are important for modern scientists to recognize because they demonstrated consciousness, a preexisting life, and an awareness of what is no longer alive. Some of the best documented instances of such fossil legends are in North and South America, coming through Native American traditions. For a thorough coverage of this topic, I recommend reading Adrienne Mayor's 2005 book, Fossil Legends of the First Americans. In this book, she argues persuasively that many Native American tribes had stories directly connected to prehuman fossils on their ancestral lands. For example, the Iroquois, Shawnee, and Delaware tribes in the eastern part of North America, were aware of Pleistocene fossils of extinct bears, mastodons, mammoths, and bison. In what is now the southwestern US, the Zuni, Navajo, Apache, and other tribes had stories related to dinosaur bones and tracks. In the mid-continent, the Sioux, Comanche, Cheyenne, and many other tribes explain the presence of gigantic fossil bones from Mesozoic and Cenozoic rocks through their own stories. Going further south, Spanish invaders in the 16th through the 18th centuries mentioned how Incans and Aztecs similarly accounted for the fossil remains of mammals and other extinct animals that were native to Central and South America. But what's really interesting to me is to think about indigenous people who actually lived alongside some of these now extinct species and documented their existence before these species went extinct. The most famous evidence for humans and now extinct species living together comes from cave paintings in Europe. These paintings, some of which are 35,000-40,000 years old and hence from the Pleistocene epoch, depict mammoths, woolly rhinoceroses, aurochs which were the ancestors of modern domestic cattle, bison, horses, and other large mammals alive then. More recently in 2014, archaeologists, not to be confused with paleontologists of course, discovered cave art in Indonesia of about the same age also showing animal figures that lived there then. Meanwhile in Australia, where humans have lived for perhaps longer than 50,000 years, cave art illustrates giant flightless birds, large marsupial predators, and other animals that went extinct more than 20,000 years ago. More than a few indigenous Australian cultures share a myth about an animal called a bunyip, which was a big aquatic mammal. Some researchers think this mythical animal may have been inspired by the Pleistocene marsupial diprotodon, which was a 1-2 ton marsupial that overlapped with humans in Australia before it went extinct. Even farther back in the geologic past of Australia were dinosaurs. For example, along the coast of much of Western Australia, [inaudible] people of Western Australia have a creation story about Morola, the emu man. In this story, Morola left tracks of his journey along the coast, a journey recorded in the rocks of Western Australia. Emus are large modern flightless birds of Australia that leave three-toed tracks, similar to the three-toed tracks made by carnivorous dinosaurs called theropods. So the thousands of theropod tracks in these rocks of Western Australia, along with thousands of other dinosaur tracks made there more than a 100 million years ago, were recognized by people as the tracks of formerly living beings. For the last example of a legend related to real animals, let's talk about dragons. Now these mythical animals seemingly never go out of style, showing up in popular culture ranging from kids cartoons and movies to blockbuster TV series, where they are unleashed by mothers of dragons to incinerate their foes. In parts of China where dragons feature prominently in their folklore, dinosaur bones were also called dragon bones. These real fossil bones were actually ground up and used in traditional Chinese medicine, which is yet another reason for accurate labeling of pharmaceutical products. Now, has there ever been an overlap between premodern accounts of extinct animals and modern science that help better understand how extinctions happened? Yes. In a 2014 study, a team of ecologist examined depictions of mammals in Egypt dating back as far as 6,000 years ago, which they combine with other archaeological data to test how the mammal diversity changed in that area over time. They concluded that the number of large mammal species there decreased traumatically over that time, going from 37 to just eight. The main reasons they proposed for this drop in diversity was from a combination of three factors: increased aridity which changed formerly wetter environments to deserts, changes in the ecological community especially predators and their prey, and the collapse of human societies related to these ecological changes. Now given all of this human recognition of fossils as belonging to a prehuman past or even overlapping with humans during the Pleistocene epoch, when did modern scientific methods start taking us down a path to better understand the nature of extinctions including their causes? Surprisingly, modern concepts of extinctions have only developed in the past few 100 years, and these concepts were fiercely debated when they were first proposed in a formal way. So in our next class, we'll talk about the early development of the sciences that lead to better understanding extinctions of the past, present, and future.
