Human evolution

Published on July 31, 2022   36 min

Other Talks in the Series: Introduction to Evolutionary Biology

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This is Vagheesh Narasimhan. I'm an assistant professor at the University of Texas, Austin. I'm going to talk to you today about human evolution.
I'd like to begin by saying that the study of human evolution is something that has fascinated generations of scientists. Charles Darwin, of course, famously wrote a book about human origins, where he got many basic things right, including our relationship with the great apes, as well as the origin of modern humans being in Africa.
One of the most obvious ways to understand human origins is to compare ourselves to our closest relatives, the great apes. Prior to molecular methods looking at genomes, this was carried out primarily by examining anatomical differences between the great apes and us. For example, we are the only great apes to have longer legs than arms and we have additional anatomical changes in the pelvis and spine which allow us to walk upright.
Fortunately, we're able to look at these differences in anatomy, not just by comparing ourselves to the great apes, but over time by looking at evidence from fossils. Over the past 100 years or so, large numbers of hominin fossils have been uncovered. Hominids, as in fossils that possess particular characteristics that differentiate ourselves from the great apes, however primitive these characteristics might be. These fossils provide a way to look at our evolutionary history in steps of time. Of course, this process of drawing relationships between fossils is not exact, but it provides a record of change over time that we can use to understand the evolutionary process.
One amazing thing that these fossils allow us to do is to look at skeletal and anatomical changes in structure that have evolved over the past few million years. In particular, it allows us to look at changes that allow for bipedalism, the ability to walk upright on two legs. In this figure are a sequence that we're observing in the anatomy of the hominid lineage leading to ourselves. As you can see, the stability of these hominids being able to walk upright drastically improves over time.