▶ Your Answer :
In
the reading passage, there is ample support for the author’s claim
that polluted environments are a more plausible reason for a decrease
in the number of sea otters than aggression by predators. However,
the professor in the lecture gives several reasons as a rebuttal to
the author’s point.
First,
the professor contends that dead sea otters have not been found in
beach, which is not consistent with the pollution theory. Were
infections by pollution a truly dominant factor, the left bodies of
the otters would have remained. If anything, this observation accords
with the predator hypothesis. This is because sea otters would be
eaten immediately and could not be discovered onshore after being
dead, if they were killed by other animals. This casts doubt on the
reading passage’s claim that previously known sources of pollutants
such as oil rigs could menace the existence of sea otters secondhand.
Next,
the professor argues that an orca, which is a huge predatory whale,
could consume sea otters because of human hunters. To put it
concretely, orcas would alter their diet to survive and start eating
small mammals, because only these animals were available to them due
to hunting by people. Therefore, all of the tinier mammals such as
seals, sea lions, and sea otters decreased in number. This refutes
the reading passage’s assertion that pollution is able to perfectly
account for the decline in the number of other marine mammals, and
orcas are fond of eating larger prey rather than smaller animals.
Finally,
the professor insists that the uneven pattern of the diminishing
population of sea otters can be better described by the predator
theory. In fact, this pattern relies upon whether a place is
accessible to orcas or not. To be specific, the number of the otters
is reduced significantly in a location which can be reached easily by
orcas. In addition, orcas cannot go to shallow and rocky areas due to
their great size, so the population of sea otters in those places
remained stable comparatively. This counters the reading passage’s
suggestion that various environmental elements such as ocean currents
could disseminate pollutants unevenly, which resulted in the uneven
pattern of a decrease in sea otter populations.
For
the aforementioned grounds, the professor in the lecture maintains
that a decline in the number of sea otters can be explained most
aptly by the predator hypothesis. |