TPO43 Mobina

The main idea of both the passage and the lecture is about the theories related to the way of living of agnostides. With this in mind, the passage proposes three episodes of theories to reveal how agnostides might have lived. The lecturer, on the other hand, categorically refutes all the three theories mentioned in the passage, believing that each of the theories has serious drawback and weakness.

First, both the text and the talk discuss the idea of angnostide to be free-swimming predators. In this line of thought, the author believes that like other primitive arthropods, agnostides might have been free-swimming predators feeding from small organisms in the sea. On the contrary, the lecturer maintains that although it is true that arthropods were present in the open ocean, all of them were equipped with large, wide eyes which were the necessary implement for them to find food. However, agnostides had poorly-developed eyes and they were almost blind. Under such a circumstance, they might have other sensory organs to help them be free-swimming predators. As a result, this theory does not hold true because there was not any compelling evidence in the fossils.

Second, both the reading and the listening materials put forth the idea of agnostides to be seafloor dwellers. While the passage mentions that they might have inhabited on the seafloor just like other arthropods, the lecturer opposes this notion, citing that arthropods were not typically capable of moving swiftly and fast to go to far distances. Accordingly, they used to stay in localized area and would not travel to new environment. They occupied small areas where they originated from. However, agnostides were able to move really fast and they could inhabit in different and multiple areas. According to the lecturer, this ability to move and be spread in a vast environment is an unusual ability for seafloor dwellers.

Eventually, both the passage and the lecture talk about angosite to be parasites. In this vein, the author asserts that angostids were parasites and behave as parasitic organisms. In contrast, the lecturer maintains that parasites population was not very large and they lived within a certain limit. If the number of parasites is too high, they will kill the host organism. Since there is a great number of agnostids, this very theory would be ruled out and not hold true.