The author indicates that benefits of zoos are numerous, including protecting endangered species, facilitating the study conducted by scientists and enriching the lives of humans as well as animals. However, the speaker casts doubt on the three reasons for the argument held by the author.
Zoos can do little to save endangered species, considering the limited amount of animals kept by a typical zoo. The speaker states that zoos possess so small a number of animals that it is not of great help to save those endangered species. What's more, protecting animals through keeping them in zoos will inevitably bring some problems, like genetic problems. This perspective is quite different from the view in the passage.
Scientists probably overlook the fact that animal's behavior in capability is different from that in a wild environment, when they intent to conduct a study in a zoo. The speaker also points out that the data collected from samplers in a zoo may be inaccurate. This is the second different point the speaker has from the author.
Admittedly, zoos enrich the lives of humans in some way, but the effect depends on the motivation of the person who goes to the zoo. The speaker mentions that most people actually visit the zoo merely for entertainment goals. Also, the speaker says that there are other responsible ways to benefit people. This viewpoint of the speaker is different from the point of the author as well.