Lab #10 part B In order for chemical reactions to occur: Molecules must collide - They collide w/ a certain impact.

Lab #10 part BIn 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:

• Must have increased temperature for proper molecular collisions

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Temperatures too high (about 40oC or higher)

•May denature proteins and ultimately kill an individual

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Evolution has solved this problem:

• 1) EnzymesQuickTime™ and a

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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.

EndothermRapid Metabolism produces

much heat…

Metabolism is soooooo slow, their bodies produce

little heat…

every animal besides a bird or mammal

How does a terrestrialterrestrial ectotherm thermo regulate?

How does a terrestrialterrestrial ectotherm thermo regulate?

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What is the ADVANTAGES of ectothermy???

require very little energy… b/c their metabolism is soooo slow.

do not have to eat as often.

do not have enough energy for sustained exertion.

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How does a terrestrialterrestrial 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

can live in colder climates... HOWEVER, must have a constant food supply!!

maximize metabolic rate.

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How does an aquatic ectotherm thermoregulate?

Their metabolism speeds up or slows down?

CirculationCirculationquick reviewquick 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

• Deoxygenated bloodDeoxygenated 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.

CirculationCirculationquick reviewquick review

The effectiveness of gas exchange in some gills, including those of

fishesIs increased by ventilation and

countercurrent flow of blood and water

Countercurrent exchangeFigure 42.21

Gill arch

Water flow Operculum

Gill arch

Blood vessel

Gillfilaments

Oxygen-poorblood

Oxygen-richblood

Water flowover lamellaeshowing % O2

Blood flowthrough capillariesin lamellaeshowing % O2

Lamella

100%

40%

70%

15%

90%

60% 30

%

5%

O2

Form fits Function

Figure 42.1

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.

What is the effect on a 10oC 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.

What is the effect on a 10oC rise in temperature?

• Simply choose two points on the graph that are 10 degrees apart,

• Determine their respective rates,

• and find their quotient.

What is the effect on a 10oC 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.

Q10 =

(higher temp.)

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.