Lecture 1

Question 1

How can temperature disrupt macromolecules?

Answer 1

Protein folding & assembly
Nucleic acid secondary structure (“break DNA”)
Lipid physical state (“fluidity”)
Protein-nucleic acid interactions

Question 2

What non-covalent (“weak”) chemical bonds exist in biological structures?

Answer 2

hydrogen bonds
ionic interactions
van der Waals forces
hydrophobic effects

Question 3

Describe marginal stability in context of biological structures.

Answer 3

The tertiary structure and associated movement allowed by weak bonds, which allows the movement needed to perform its job.

Question 4

Describe the trade-off associated with weak chemical bonds in biological structures.

Answer 4

Weaker forces allow for flexibility, but make it susceptible to environmental
 stressors like temperature.

Question 5

Describe the relationship between temperature and physiological reactions in the context of speed.

Answer 5

As temperatures go up, reaction speed increases.

As temperatures go down, reaction speed decreases.

Question 6

What do environmental stresses do to physiological traits?

Answer 6

Stressors shift traits out of optimal ranges of function/structure; into sub-optimal ranges (too slow/ too fast)

Question 7

Describe Q10 effects.

Answer 7

Describes temperature sensitivity of biochemical reactions. Change temp. in 10°C intervals and find rates often change by 2-3 fold.

Question 8

Give an example of temperature effects on solute solubilities.

Answer 8

Cold liquids hold more gas than warm liquids. Increased temps reduces O2 solubility, thus, decreased temps increases O2 solubility.

Question 9

Describe how temperature affects acid-base balance.

Answer 9

Increased temps promotes dissociation of weak acids, increasing H+, lowering pH (making acidic).

Question 10

What is the upper temperature limit eukaryotic life can approach?

Answer 10

55-60°C

Question 11

What is an ectotherm?

Answer 11

An organism whose body temp. is defined by the environment.

Question 12

What is a poikilotherm?

Answer 12

An organism whose body temp. changes according to environment, but may not be identical to environment such as in the case of behavioral changes.

Question 13

What is an endotherm?

Answer 13

An organism who generates their own body heat.

Question 14

What is the difference between a heterotherm and a homeotherm?

Answer 14

A heterotherm’s body temp. is not identical throughout/ different temps. exist in different regions in body; a homeotherm’s body temp. is identical through its entire body.

Question 15

What is the difference between a stenotherm and a eurytherm?

Answer 15

Stenotherms tolerate narrow temperature range; eurytherms tolerate broad temperature range.

Question 16

What is the difference between a thermophile and a psychrophile?

Answer 16

Thermophiles are dependent on hot temperatures; psychrophiles are dependent on cold temperatures.

Question 17

What is a eurytolerant organism?

Answer 17

An organism with a wide ability to cope with diverse abiotic changes.

Question 18

What is a congeneric species? What are they commonly used to study?

Answer 18

2+ species in the same genus who are closely related as can be without being the same; good for studying thermal relationships.

Question 19

Describe the relationship between heat tolerance and vertical/ latitudinal distributions.

Answer 19

Heat tolerance is higher in lower latitudes/ higher vertical positions. Organisms in higher latitudes/ lower vertical positions (intertidal) have less heat tolerance.

Question 20

Describe the relationship between phenotypic plasticity and tolerance.

Answer 20

Some organisms can acclimate to tolerate abnormal temperatures; adjust “zone of tolerance.”

Question 21

List two examples of vertical position and thermal tolerance relationships.

Answer 21

Species from the Tegula genus and Littorina genus who had higher vertical position lasted longer/ survived at higher temps than those in lower positions.

Question 22

What is the Arrhenius “break” temperatures (ABTs)

Answer 22

The point where mitochondria stop generating ATP.

Question 23

How to Arrhenius break temperatures (ABTs) change when acclimated to heat? What is responsible for the change?

Answer 23

If you acclimate the temperature higher = ABT increases due to decreased membrane fluidity.

Question 24

Do “hot” species have ABTs nearer to or further from body temperature than “cold” species?

Answer 24

“Hot” species ABTs are NEARER TO body temperature than “cold” species.

Question 25

In hydrothermal vent ecosystems, what organisms live closer to the vents?

Answer 25

Organisms with higher ABTs are closer to the vents.

Question 26

What is LT50?

Answer 26

The temp. at which 50% the
 individuals die = the average lethal temperature.

Question 27

In the case of varied latitudinal/ vertical distribution of porcelain crabs, who has higher LT50?

Answer 27

Porcelain crabs in higher vertical distributions have higher LT50 in all latitudinal environments.

Question 28

What organisms are most threatened by rising temperatures, in context of LT50? What does this mean for predicting climate change effects?

Answer 28

Warm adapted species, as they are already living at their upper lethal temperatures. These animals will be replaced by congeners moving in to replace them. May see tropical extinctions.

Question 29

What are some of the functions that temperature effects?

Answer 29

Heart rate
Feeding rate
Nervous system activity
Biosynthesis, e.g., making new proteins
Growth rate
Reproduction
Movement

Question 30

What is the break temperature (BT)?

Answer 30

The “heartbreak” temperature; the temperature at which heart rate drops.

Question 31

What causes heart rate to increase as temperature increases?

Answer 31

Heart rate increases with increased temperature as metabolism increases.

Question 32

How is BT related to LT50?

Answer 32

BT and LT50 are correlated/ matched.

Question 33

What organism was used to study break temperature (BT)?

Answer 33

Porcelain crabs/ genus Petrolisthes

Question 34

Describe the effects of acclimation on heat tolerance.

Answer 34

Acclimation increases heat tolerance to some extent; but animals living closer to upper limit could not increase heat tolerance as well.