The material discusses the possible reasons that cause sea otter's declining. While the reading claims that the pollution hypothesis is the more likely reason, the listening disagrees and mentions that the predation theory is the most suitable explanation.
First, the author states that the decline happened along the Alaskan coast, where there was a lot of industrial chemical pollution. On the other hand, the professor refutes this and posits that if pollution is the reason, so there should be died sea otters. The lecturer adds the absence of killed otter because the predators ate them. The speaker explains that consistency with the predation theory.
Second, the writer contends that there were other mammals in the same area that were declining too. On the contrary, the lecturer opposes this and states that orcas used to eat whales, and when whales disappeared, they had to search for other food sources to survive. The professor says that orcas hunted other mammals, such as sea lions, seals, and sea otter. As a result, their numbers declined.
Third, the reading states that the uneven pattern of declined could strengthen the pollution hypothesis. Conversely, the professor contradicts this and points out that uneven pattern of declining because orcas could not access all places evenly. The lecturer adds the orcas are very large so they could not access shallow and rocky places. The speaker states that shallow and rocky places are the locations where sea otters have not declined.
The material discusses the possible reasons that cause
sea
otter's declining. While the reading claims that the
pollution
hypothesis is the more likely reason, the listening disagrees and mentions that the predation theory is the most suitable explanation.
First
, the author
states
that the decline happened along the Alaskan coast, where there was
a lot of
industrial chemical
pollution
. On the
other
hand, the professor refutes this and posits that if
pollution
is the reason,
so
there should be
died
sea
otters. The lecturer
adds
the absence of killed otter
because
the predators ate them. The speaker
explains
that consistency with the predation theory.
Second, the writer contends that there were
other
mammals in the same area that were declining too.
On the contrary
, the lecturer opposes this and
states
that orcas
used
to eat whales, and when whales disappeared, they had to search for
other
food sources to survive. The professor says that orcas hunted
other
mammals, such as
sea
lions, seals, and
sea
otter.
As a result
, their numbers declined.
Third, the reading
states
that the uneven pattern of declined could strengthen the
pollution
hypothesis.
Conversely
, the professor contradicts this and points out that uneven pattern of declining
because
orcas could not access all places
evenly
. The lecturer
adds
the orcas are
very
large
so
they could not access shallow and rocky places. The speaker
states
that shallow and rocky places are the locations where
sea
otters have not declined.