KC Field Museum Week 2

1 - In Wonderful Life Gould hypothesizes on cultural values, assumptions, and what kind of logic are evident in the original interpretation of the Burgess Shale, and then the change in thinking that led to its recent re-interpretation. What model of biodiversity and evolutionary change does Gould argue resulted in the earlier error in classifying the Burgess Shale animals? What is the original cultural/historical source of that model, or what he calls “iconography”? -The earlier classification of the Burgess Shale was based on the theory that organisms improve over time, as in they become more complicated and just overall better for their environment. It hypothesizes that the earlier stages of an animal were simpler, a dumbed down version, and they get more complex over time. This is obviously inaccurate. Through this same line of thinking, this classification was “The Great Chain of Being” by A.O. Lovejoy’s way of trying to put extinct animals under the same classifications that exist for present animals. 2 - Notice that much of Gould’s argument centers on discussing evolutionary tress (phylogenies) of the kind you constructed on a small scale. At the end of the chapter we see he is interested in the overall shapes (“topology”) of the phylogenies. Why? What does he claim that the shape of phylogenies imply about how evolution happens over long stretches of time that had been neglected by biologists? What kinds of causal factors alter the course of evolution, the shape of phylogenies, and the eventual designs of organisms that we see today? -The evolutionary trees aka the phylogenies are shaped based on the perceptions of the evolutionary path a species has taken over the entirety of its existence. Some think that a species gets more and more complicated as they get higher up in the tree, but that perception is inaccurate. Regardless of where an animal is depicted on the evolutionary tree, it is adapted and equally as complicated as the current form of the species. The positioning of the animals on the tree only implies age and time period, not complexity. Maybe a horizontal format would be more effective? Other misconceptions about the tree are that a smaller, more refined branch implies a superior and perfect example of evolution, but is actually not very successful. An example of casual factors would be habitat change or alterations based on disasters, and what traits survive and become dominant from those external variables. 2b - Related: What does it mean to “replay the Tape of Life” and why is this an interesting idea to Gould? Relate Gould’s preferred model with the views of early Catastrophists – what would Cuvier (if alive) like and not like about Gould’s interpretation? -it means that if we could turn back time, and attempt to recreate evolution as an experiment, to see if the same result would be possible. It is a fascinating concept, to test whether the same result is possible or not. Gould’s assessment is that there was and is so much chance involved, that the same result would be impossible, and even evolution would be different. Curvier, in my opinion, would agree with Gould. How catastrophes would differ and effect evolution and even which species are alive today, and how their traits would vary. 3 - What is “disparity” versus “diversity”? Give an original example (one not given in the reading). -Disparity is when there are fewer branches on a segment of the evolutionary tree, which represents less variation within a group. Diversity is a greater number and more variation on a branch or a segment of the evolutionary tree, or greater variations in a species or group. An example would be finches, because there are many types of them, and they are closely related but have adapted to very specific environments, such as the islands we talked about earlier in class. 4 - In the reading Evolution by Walking what is so interesting about how the American Museum of Natural History has changed their mammal display? Why is it significant in how we think about biodiversity in his opinion? -The American Museum of Natural History’s order of display was rearranged to be in a phylogenic order, rather than the dated idea of a chronological order.