TPO 43

The reading passage and the lecturer discuss a group of marine animals that lived in the ocean, and fossils are founded in rocks in many areas. They named Agnostids, and the information from their fossils are not completed, so the paleontologists do not determine how these animals behaved or ate. Although the reading provides three theories about the lifestyle and behavior of Agnostids, the speaker refutes these ideas through several reasons, which I will describe in this report.

First, the passage points out that the Agnostids would have been free-swimming predators because other types of primitive arthropods were predators for sea animals. The lecturer, in contrast, rejects this by claiming that all free-swimming predators have special organism to find their prey. Most of them have developed and large eyes that can see their prey easily. However, the agnostids had tiny and small eyes, and some of them were blind. So, they must have other organisms to find prey, but their fossils do not show them.

Furthermore, the passage states that the agnostids would see dwellers that lived in the seafloor and ate dead organisms or bacteria. However, the professor argues that the seafloor dwellers do not have the ability to moving fast or going the far distance. They live in a local place and small geographic area. But, the Agnostids would habitant in multiple geographic eras, and they would have the ability to moving fast and going the far distance. Therefore, it is unlikely for agnostids to be seafloor dwellers.

Finally, although the passage says that the Agnostids may have been parasites that lived on larger organisms and feeding off them. The speaker disagrees by mentioning that the population of the parasites must be small because they live and feed on other animals body, and if their population become a large, they would kill off host animals. As we know, the population of the Agnostids were large numbers, and their fossils were founded in many eras. So they could not be parasites.