The material discusses the reasons for sea cows' extinction. While the reading suggests three theories that could explain this extinction, the listening disagrees and mentions that the truth is they do not the main reason for sea cows' extinction and there is a problem with each theory of the reading.
First, the author says that sea cows were extinct because of overhunting by Siberian people. On the other hand, the professor challenges this and states that sea cows were massive, one of them was nine-meter-long and weighed ten tons. Furthermore, the lecturer explains that a couple of sea cows could feed Siberian people for a month. the speaker adds that Siberian's population was not very large, so they did not need to hunt a lot of sea cows. The professor cits that overhunting by Sioberain people is not the reason for sea cows' extinction.
Second, the writer states that sea cows were extinct because of ecosystems disturbances that declined their main source of food, which was kelp. On the contrary, the professor opposes this and contends that if there was an ecosystem disturbance before 1968, so not just kelps might decline. The lecturer explains that other marine, such as whales should be diminished too. The speaker adds that there was no report about the declining of other creatures during this period. The professor concludes that kelp grew fine and sea cows did not have any experience of food shortage.
Third, the reading posits that the arrival of the European fur traders was the main reason for sea cows' extinction. Conversely, the lecturer contradicts this and mentions that sea cows were extinct soon after European arrival. The professor cits that sea cows' population was already quite small a hundred years before European fur traders reached the island. The speaker contends that if sea cows declined long before European fur traders' arrival to the island, they were not the main reason for sea cows extinction.
The material discusses the
reasons
for
sea
cows'
extinction
. While the reading suggests three theories that could
explain
this
extinction
, the listening disagrees and mentions that the truth is they do not the
main
reason
for
sea
cows'
extinction
and there is a problem with each theory of the reading.
First
, the author says that
sea
cows
were extinct
because
of overhunting by Siberian
people
.
On the other hand
, the
professor
challenges this and states that
sea
cows
were massive, one of them was nine-meter-long and weighed ten tons.
Furthermore
, the lecturer
explains
that a couple of
sea
cows
could feed Siberian
people
for a month.
the
speaker
adds
that Siberian's population was not
very
large,
so
they did not need to hunt
a lot of
sea
cows
. The
professor
cits
that overhunting by
Sioberain
people
is
not the
reason
for
sea
cows'
extinction.
Second, the writer states that
sea
cows
were extinct
because
of ecosystems disturbances that declined their
main
source of food, which was kelp.
On the contrary
, the
professor
opposes this and contends that if there was an ecosystem disturbance
before
1968,
so
not
just
kelps
might decline. The lecturer
explains
that other marine, such as whales should
be diminished
too. The speaker
adds
that there was no report about the declining of other creatures during this period.
The
professor
concludes that kelp grew fine and
sea
cows
did not have any experience of food shortage.
Third, the reading posits that the arrival of the European fur traders was the
main
reason
for
sea
cows'
extinction
.
Conversely
, the lecturer contradicts this and mentions that
sea
cows
were extinct
soon
after European arrival. The
professor
cits
that
sea
cows'
population was already quite
small
a hundred years
before
European fur traders reached the island. The speaker contends that if
sea
cows
declined long
before
European fur traders'
arrival to the island
, they were not the
main
reason
for
sea
cows
extinction
.