In this lecture, the key concepts are homology, serial homology, gene regulation, and the geological timeline. I introduce the vertebral column and the number of vertebrae of different types in humans, gorillas, orangutans and macaques. Looking at some data from Adolph Schultz, we examine the variation in vertebra count among humans and some other species of primates. To discuss the concept of variation in segment numbers, I turn to Hox genes and segmentation patterning in early embryos. Homology of the Hox genes between fruit flies, mice and humans mirrors the homology of segmentation, including vertebrae counts. Finally, I get to some Miocene apes and their lumbar vertebral anatomy, focusing on Nacholapithecus, Morotopithecus and Proconsul.
This one stopped a bit short of where I wanted to go, but it's a neat combination of topics in anatomy and development.
This is a continuing experiment in sharing the lectures for the course online. For my explainer, you can see Lecture 2: Feet.
- What other parts of the body reflect serial homology?
- The lecture used wings in birds as an example of homology. What other natural examples can you think of?
- What is another natural example of convergence or parallelism?
- Why can we use mice to learn about development in humans?