Lab #10 part B
In order for chemical reactions
to occur:
• Molecules must collide • They collide w/ a certain impact
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In order for chemical reactions
to occur:
• The greater their kinetic energy…
• The greater their force of collision
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The greater the kinetic
energy… the greater the force
of collision
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TEMPERATURE IS
A MEASURE OF
KINETIC ENERGY!
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Increase in
temperature …
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leads to
an
increase
in
collisions
…
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Living organisms need the
proper temperature for proper
amount of collisions
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Living organisms have a temp.
dilemma:
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• Must have
increased
temperature for
proper molecular
collisions
Temperatures too high (about
40oC or higher)
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• May
denature
proteins
and
ultimately
kill an
Evolution has solved this
problem:
• 1) Enzymes
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Evolution has solved this
problem:
• 2) Behavioral,
morphological
and
physiological
traits
designed to
maintain a
warm body…
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Ectotherm vs. Endotherm
Rapid Metabolism produces
much heat…
Metabolism is soooooo
slow, their bodies produce
little heat…
every animal besides a bird
or mammal
How does a terrestrial ectotherm
thermo regulate?
How does a terrestrial ectotherm
thermo regulate?
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What is the ADVANTAGES of
ectothermy???
require very little energy…
b/c their metabolism is soooo
slow.

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do not have enough energy
for sustained exertion.


do not have to eat as often.
How does a terrestrial endotherm
thermo regulate?
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Maximize blood flow
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Insulating fat, feathers,
or fur
What is the ADVANTAGES of
endothermy???
elevated, constant body
temperature, despite
changes in environment

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
maximize metabolic rate.
can live in colder climates...
HOWEVER, must have a
constant food supply!!

How does an aquatic
ectotherm thermoregulate?
Their metabolism speeds up
or slows down?
Circulation
quick review
• Water flows over
gills as fish swims
• Gills are made of
thousands of gill
filaments
• Fish, open their
mouths, and H2O
flows over the gills
Circulation
quick review
• Deoxygenated blood
flows into the gills
• Oxygen flows from
the water into the
gills and is picked
up by the blood.
• It goes to the rest of
the body.
The effectiveness of gas exchange
in some gills, including those of
fishes
Is increased by ventilation and
countercurrent flow of blood and
water
Gill arch
Gill
arch
Water
flow
Oxygen-poor
blood
Oxygen-rich
Blood blood
vessel
Lamella
Operculum
Blood flow
Water flow
through capillaries
over lamellae
in lamellae
showing % O2
showing % O2
Countercurrent exchange
O2
Figure 42.21
Gill
filaments
Form fits
Function
On with the Lab…
The lab examines the relationship
between metabolic rate & body
temp. in ectotherms
We will measure the heart rate
(indirectly) to measure metabolism
• The rate of metabolism in
ectothermic animals
increases as the
environmental temperature
increases
• This rise occurs because the
reactants in the cell have
greater thermal energy, and
many cellular enzymes are
more active as temperature
increases.
o
10 C
What is the effect on a
rise in temperature?
• The relationship
between temperature
changes & metabolic
rate is often
measured as Q10.
• If the metabolic
rate doubles with a
10°C increase in
temperature, then
Q10 = 2.
o
10 C
What is the effect on a
rise in temperature?
• Simply choose two
points on the graph
that are 10 degrees
apart,
• Determine their
respective rates,
• and find their
quotient.
o
10 C
What is the effect on a
rise in temperature?
• The usefulness of
calculating a Q10 value is
that it suggests whether or
not the metabolic reactions
being examined are
controlled by temperature
or by some other factor.
IF Q10 IS NOT 2 (aprx.)
SOMETHING BESIDES TEMP. IS
AFFECTING THE RATE!
If the Q10 = 3… then for every
10oC increase in temp /
metabolic rate would TRIPLE
• Q10 measures the
increase in metabolic
activity resulting from an
increase in body
temperature.
You can measure Q10
indirectly, by measuring heart
rate
beats
min.
(higher temp.)
Q10 =
Rate at temperature
“X” + 10oC
Rate at temperature
“X”
(lower temp)
Q10 is the ratio of the rate of a reaction at one
temperature divided by the rate of the same
reaction at a temperature 10 C° less.
The larger the Q10 the greater the effect the
temperature has on the reaction. A value of
Q10 = 1 implies temperature has no effect
on the reaction.