Transcript of Slides Introduction Lecture ANTH 18630 Fall 2011 Slide 3 A phylogenetic tree is a visual representation of how taxa are related to one another The points labeled for example y and x are called nodes Nodes indicate most recent common ancestors abbv MRCA Each node branches into two lines called lineages Lineages are comprised of both extinct and living taxa The taxa fish frog lizard mouse human shown at the tips of each lineage are living representatives of the lineage These are called tip taxa In this phylogenetic tree is the frog more closely related to the fish or the human Most people look at the phylogenetic tree on the left and say the frog is more closely related to the fish because the frog is placed beside the fish In the tree on the right node x has been rotated moving the frog furthest from the fish The key to answering this question is not to focus on the tip taxa Rather focus on the nodes or most recent common ancestors Node y is the common ancestor of the lineages leading to fish frog lizards mouse and human Node x is the common ancestor of the lineages leading to frog lizard mouse and human Node y is a earlier ancestor than x All the taxa that derive from node x are tetrapods making all the taxa more closely related to one another than any is to fish a non tetrapod So the frog is more closely related to the human because frog and human share a more common recent ancestor node x This is a phylogenetic tree depicting living representatives of the Primate Order red branches on tree Mouse a non primate mammal is shown as an outgroup green branch on tree Not all primate taxa are shown As you can see from the figure the lineage leading to primates diverged from the common ancestor with the lineage leading to rodents approximately 75 million years ago Galagos are living representatives of the earliest primates which diverged from common ancestors as early as 63 million years ago More recent primate lineages include the New World monkeys such as the capuchin monkey Old World monkeys such as the baboon apes such as chimpanzee and humans we are the only living representative of our lineage The lineage leading to chimpanzee and the lineage leading to human diverged from their common ancestor only about 7 million years ago Thus chimpanzee and human are the closest living primates As we will learn in class there are fossil representatives along each lineage The last third of this class will focus on the fossil lineages leading to human AFTER divergence from the common ancestor with chimpanzee This lineage is called the hominid lineage we are the only remaining living representatives of the hominid line Homo erectus is an important hominid fossil lineage It shares our genus Homo but is a separate species Homo neanderthalensis is another important hominid fossil lineage Recently scientists have been able to sequence the DNA genome of Neandertals and compare it with that of our own All members of our species Homo sapiens shared a most recent common ancestor approximately 200 000 years ago Cro Magnon are early Homo sapiens that lived in France FIGURE 1 4 The Six Big Events of Human Evolution Bipedalism The upright bipedal two footed gait was the first hallmark feature of our hominid ancestors Slide 4 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Transcript of Slides Introduction Lecture ANTH 18630 Fall 2011 Slide 12 FIGURE 1 4 The Six Big Events of Human Evolution Nonhoning Chewing Humans nonhoning chewing complex left lacks large projecting canines in the upper jaw and a diastema or gap between the lower canine and the first premolar The chewing complex of apes such as gorillas right has large projecting upper canines and a diastema in the lower jaw to accommodate them FIGURE 1 4 The Six Big Events of Human Evolution Speech Although other animals use noises and calls to communicate basic ideas only humans can speak and through speech express complex thoughts and ideas The shape of the hyoid bone is unique to hominids and reflects their ability to speak FIGURE 1 4 The Six Big Events of Human Evolution Dependence on Material Culture Humans production and use of stone tools is one example of complex material culture The tools of our closest living relatives the chimpanzees do not approach the complexity and diversity of modern and ancestral humans tools FIGURE 1 4 The Six Big Events of Human Evolution Hunting Humans relatively large brains require lots of energy to develop and function Animal protein is an ideal source of that energy and humans obtain it by eating animals they hunt To increase their chances of success in hunting humans often employ tools and cooperative strategies FIGURE 1 4 The Six Big Events of Human Evolution Domestication of Plants and Animals Humans domesticate a wide variety of plants and animals controlling their life cycles using them as food Slide 13 Slide 14 Slide 15 Slide 16