Lecture 4

Question 1

Which basic problems does some individuals need to solve?

Answer 1

• Acquire energy, nutrients, or resources necessary to grow and develop
• Must survive to reproductive age
• Acquire energy, resources or mates necessary to reproduce and rear offspring

Question 2

Why are solutions difficult?

Answer 2

• Large number of environmental factors affecting survivorship, growth and reproduction
• Enormous variation in these factors in time and space.

Question 3

One approach to explaining the distribution and abundance
of organisms is to understand how individuals cope with…

Answer 3

environmental factors

Question 4

Physiological ecology

Answer 4

The study of the biophysical, biochemical and physiological processes used by plants and animals to cope with factors of their physical environment, or employed during ecological interactions with other organisms.

Question 5

Factors in physiological ecology

Answer 5

• Abiotic
• Biotic

Question 6

Types of abiotic factors

Answer 6

• Resource: abiotic factor that is consumed by an organism or made less available to others. Food, water…
• Condition: a varies in time and space and to which organisms respond differently. Temperature, salinity, humidity.
• Temperature is one of the most ecologically significant factors, and also one of the most relevant in the face of global climatic change. Organisms have evolved a multitude of mechanisms for regulating the temperature of their bodies in order to flourish in their particular environment.
• Water availability is another major focus in physiological ecology. The bodies of all organisms contain water, and organisms in all environments expend energy to maintain their internal pool of water and dissolved substrates.
• Environmental stressors may include climate change, nutritional variability, disease, and exposure to toxins

Question 7

Poikilotherms

Answer 7

body temperature fluctuates with ambient temperature of environment.

Question 8

Homeotherms

Answer 8

maintain relatively constant body temperature despite changes in environmental temperature

Question 9

Heterotherms

Answer 9

poikilotherm + homeotherm

Question 10

Ectotherms

Answer 10

regulate body temperature by selecting appropriate thermal environments

Question 11

Endotherms

Answer 11

regulate body temperature by using internal metabolic processes

Question 12

Humans are
a. Homeotherms
b. Heterotherms
c. Ectotherms
d. Ectothermic homeotherms

Answer 12

a. Homeotherms

Question 13

Which of the following is an advantage of homeothermy?
a. Ability to have a large caloric intake
b. Maximum allocation of energy to growth
c. Possibility of being active regardless of external temperature
d. Wide fluctuations in body temperature

Answer 13

c. Possibility of being active regardless of external temperature

Question 14

Torpor

Answer 14

Animals that normally maintain a high body temperature permit it to drop under certain conditions. i.e. BATS

Question 15

Which organisms make up the majority of endotherms?
a. Insects
b. Fish
c. Birds
d. Mammals
e. Birds and mammals combined

Answer 15

e. Birds and mammals combined

Question 16

Graph endotherms

Answer 16

The thermal neutral zone, (MR does not change with temperature) Es plano

Question 17

Ectotherms graph

Answer 17

There is not a thermal neutral zone, there is a performance optima

Question 18

How do we measure a Thermal Performance Curve?

Answer 18

Performance: correlates to fitness

Question 19

Which are limits in thermal performance curve?

Answer 19

• Dynamic using max critical temperature and min critical temperature
• Static using Upper and Lower Lethal Temperature. 50 = 50% so temperature at which 50% of organisms die

Question 20

What does the lower critical thermal limit mean?

Answer 20

Cellular fluids freeze and cells burst, some freeze to death, other recover.
- Slowed muscle contractions, ATP production and decline in nervous functions

Question 21

What does the higher critical thermal limit mean?

Answer 21

• Reduction in metabolic efficiency
• Oxygen limitation and ferementative metabolism. The O2 supply is maximized and the fermentative ATP production does not require O2, but is less efficient.
• The cellular stress produces heat shock

Question 22

Does the physiological responses to temperature have a very important ecological implication?

Answer 22

Yes

Question 23

An organism’s thermal neutral zone…
a. Is the range of body temperatures the organism can survive in
b. Only occurs for endotherms
c. Is the range temperature in which the metabolic range cgange to maintain body temperature constant
d. All of the above

Answer 23

b. Only occurs for endotherms

Question 24

Torpor
a. Occurs when an organism allows its body temperature to drop
b. Occurs only in some mammals and birds
c. Occurs in ectotherms when body tempertures drops in low ambient temperatures
d. A and B are correct
e. All of the above are correct

Answer 24

d. A and B are correct

Question 25

In a thermal performance curve, the optimal Ta (ambient temperature) range for a (n) ______, is narrower than a(n)_____ a. ectotherm, endotherm b. endotherm, ectotherm c. homeotherm, heterotherm d. the optimum Ta rane is the same for all organisms

Answer 25

a. ectotherm, endotherm