The reading and the lecture are both about the decline in sea otter populations. While the reading’s author states that pollution is a cause of their populations declining, the lecturer suggests that the greatest factor is predation. The lecturer casts doubts on the main points made in the reading by providing three reasons.
First of all, according to the reading, higher levels of pollutants in water samples support the pollution theory. However, the lecturer disputes this by explaining that if sea otters had been killed by pollutants in water, their remains would appear on shores, which indicates predators ate the sea otters.
Secondly, the reading states that populations of other small sea animals have been hurt by pollution. Nevertheless, the lecturer refutes this argument. He argues that because the whale population decreased, nearby orcas had to eat otters instead.
Finally, the reading claims that pollutant concentration can explain the uneven pattern of diminishing sea otter populations. On the other hand, the lecturer believes that this uneven population decline corresponds with the prevalence of orcas in different areas. He thinks that the otter population declines more in places with orcas, and less in those inaccessible to orcas.
In conclusion, although the reading and the lecture both concern hypotheses about diminishing sea otter populations, the three main points made in the reading are effectively challenged by the lecturer.
The
reading
and the lecture are both about the decline in
sea
otter
populations
. While the
reading’s
author states that pollution is a cause of their
populations
declining, the
lecturer
suggests that the greatest factor is predation. The
lecturer
casts doubts on the main points made in the
reading
by providing three reasons.
First of all
, according to the
reading
, higher levels of pollutants in water samples support the pollution theory.
However
, the
lecturer
disputes this by explaining that if
sea
otters had
been killed
by pollutants in water, their remains would appear on shores, which indicates predators ate the
sea
otters.
Secondly
, the
reading
states that
populations
of other
small
sea
animals have
been hurt
by pollution.
Nevertheless
, the
lecturer
refutes this argument. He argues that
because
the whale
population
decreased, nearby orcas had to eat otters
instead
.
Finally
, the
reading
claims that pollutant concentration can
explain
the uneven pattern of diminishing
sea
otter
populations
.
On the other hand
, the
lecturer
believes that this uneven
population
decline corresponds with the prevalence of orcas in
different
areas. He
thinks
that the otter
population
declines more in places with orcas, and less in those inaccessible to orcas.
In conclusion
, although the
reading
and the lecture both concern hypotheses about diminishing
sea
otter
populations
, the three main points made in the
reading
are
effectively
challenged by the
lecturer
.