TPO 43 integrated essay

The reading passage introduces three possible theories about how agnostids may have lived. However, the professor in the lecture points out that the three theories are not convincing.

First of all, the reading passage mentions that agnostids may have been free-swimming predators that to prey smaller animals in open water. Yet, the lecture states that free-swimming predators should have large and well-developed eyes which agnostids have poorly developed or even blind eyes. If they don't have good eye sight, they must equip with special sensory organs to help them hunt animals in the water. Unfortunately, there is no evidence shows in fossils that they have the special ability.

Apart from that, the reading suggests that agnostids are seafloor dwellers which is similar to primitive anthropods. Nevertheless, the lecturer disagrees with the idea. She states that seafloor dwellers tend to swim slowly. They stay in limited area and occupied the place they were born. Unlike seafloor dwellers, agnostids are spread large distances. That is to say, they can’t be seafloor dwellers.

Last but not least, the reading states that agnostids are parasites that relying on larger organisms. Once again, the lecturer contradicts the hypothesis. She claims that parasites should be small in population. That is because if there are too many parasites, many host organisms will be killed. To be more specific, agnostids show in fossil that they are large in number. So, they are not parasites.