The passage and lecture both talk about whether dinosaurs are endotherms(animals who keep their body temperature constant all the time) or not endotherms. The passage strongly puts forward three major theories to prove that dinosaurs must be endotherms. But the lecturer refutes the theories and presents alternative perspective to prove that dinosaurs might not be endotherms.
First of all, the author of passage presents the fact that dinosaurs bones have been discovered in the polar region. This implies that dinosaurs must have lived in polar regions and since polar region is extremely cold only animals that can keep their body temperature can survive in such conditions. This provides evidence that dinosaurs must have been endotherms. But the lecturer contrasts this by presenting another theory that in the era of dinosaurs, the polar region might have been much more warmer than they are now. She also presents another idea that maybe dinosaurs used to migrate away from polar region in winter.
Furthermore, the author talks about the position of legs in dinosaurs. From the study of fossils, it is clear that the legs in dinosaurs were positioned underneath their body. This is the case for most modern endotherms. So, dinosaurs must be endotherms. Here, the lecturer argues that the position of legs might be in order to support the huge weight of dinosaurs. Since dinosaurs grow huge in size, the position of legs underneath the body provides benefit to them.
Finally, the author presents another fact that study of fossils of dinosaurs prove that they have dense Haversian canals present in their bone structures which indicates that they must have been endotherms since most endotherms have this canal today. Here, the lecturer agrees that dinosaurs have the Haversian canals present in their body. However the study of the canals show that the growth of dinosaurs was not consistent with time. This might mean that maybe dinosaurs grew slower in cold climate and faster in warm climate. Since endotherms tend to show fast growth, the study of the Haversian canals indicates that dinosaurs might not be endotherms.
The passage and lecture both talk about whether dinosaurs are endotherms(animals who
keep
their
body
temperature constant all the time) or not endotherms. The passage
strongly
puts forward three major theories to prove that dinosaurs
must
be endotherms.
But
the
lecturer
refutes the theories and
presents
alternative perspective to prove that dinosaurs
might
not be endotherms.
First of all
, the author of passage
presents
the fact that dinosaurs bones have
been discovered
in the
polar
region
.
This implies that
dinosaurs
must
have
lived
in
polar
regions
and since
polar
region
is
extremely
cold
only
animals that can
keep
their
body
temperature can survive in such conditions. This provides evidence that dinosaurs
must
have been endotherms.
But
the
lecturer
contrasts this by presenting another theory that in the era of dinosaurs, the
polar
region
might
have been much
more warmer
than they are
now
. She
also
presents
another
idea
that maybe dinosaurs
used
to migrate away from
polar
region
in winter.
Furthermore
, the author talks about the position of
legs
in dinosaurs. From the
study
of fossils, it is
clear
that the
legs
in dinosaurs
were positioned
underneath their
body
. This is the case for most modern endotherms.
So
, dinosaurs
must
be endotherms. Here, the
lecturer
argues that the position of
legs
might
be in order to support the huge weight of dinosaurs. Since dinosaurs grow
huge in size
, the position of
legs
underneath the
body
provides benefit to them.
Finally
, the author
presents
another fact that
study
of fossils of dinosaurs prove that they have dense
Haversian
canals
present
in their bone structures which indicates that they
must
have been endotherms since most endotherms have this canal
today
. Here, the
lecturer
agrees
that dinosaurs have the
Haversian
canals
present
in their
body
.
However
the
study
of the canals
show
that the growth of dinosaurs was not consistent with time. This
might
mean that maybe dinosaurs grew slower in
cold
climate and faster in warm climate. Since endotherms tend to
show
fast
growth, the
study
of the
Haversian
canals indicates that dinosaurs
might
not be endotherms.