ROT 1: Model Endotherm

Question 1

Metabolic rate

Answer 1

the net rate at which chemical reactions are occurring within an organism under specified conditions.

Question 2

list some factors that affect metabolic rate

Answer 2

activity, body size, AMBIENT temperature, and altitude.

Question 3

____ utilize heat produced from ___ ___ ___ to maintain a high and constant body temperature

Answer 3

ENDOTHERMS utilize heat produced from INTERNAL CHEMICAL REACTIONS (metabolism) to maintain a high and constant body temperature.

Question 4

body temperature of ____ varies with fluctuations in the external environment

Answer 4

ECTOTHERMS.

Question 5

metabolic rate _____ with the mass of the organism, with a linear relationship of ___.

Answer 5

metabolic rate INCREASES with the mass of the organism, with a linear relationship of 0.75.

Question 6

metabolic rate would ideally have a relationship of ___ with surface area of the animal. why?

Answer 6

0.67. Because area is related to the volume/mass raised to the 2/3.

Question 7

metabolic rate vs specific metabolic rate

Answer 7

metabolic rate isjust the general rate at which chemical reactions are occuring, but specific metabolic rate is the rate at which chemical reactions are occuring PER UNIT MASS.

Question 8

specific metabolic rate ____ as total mass increases. why?

Answer 8

DECLINES. because as mass increases, the surface area/mass(volume) ratio decreases, less energy (through metabolic reactions) is required to maintain constant temperature

Question 9

2 means that endotherms maintain body temperature

Answer 9

1) metabolic thermoregulation

2) physical thermoregulation; head loss from the body is regulated by a variety of physiological devices (fut, fat etc.

Question 10

examples of how endotherms physically thermoregulate

Answer 10

1) fur
2) brown fat
3) shivering
4) vasomotor activity –> blood vessel constriction/dilation

Question 11

animals thermoregulate using a ___ ___ system

Answer 11

negative feedback system

Question 12

surface area of sphere

Answer 12

4pi(r^2)

Question 13

outline 3 ways we prevented heat loss in the lab

Answer 13

1) moving to still air (away from fan/”wind”
2) maintaining core body temperature and allowing periphery to vary
3) insulation

Question 14

the slope of a graph plotting log mass (x axis) and log SPECIFIC heat loss should be ____. Why

Answer 14

NEGATIVE. as the mass increases (as log mass increases), the surface area/volume ratio DECREASES, and LESS energy is required to maintain the temperature of each gram of tissue.

Question 15

as volume increases by a power of three, the surface area increases by a power of ___

Answer 15

2. So if you double the mass/volume, you get a 2/3 increase in surface area.

Question 16

T/F a smaller animal is more metabolically active than a large animal. What specializations do their cells have?

Answer 16

TRUE. smaller animals have higher surface area/mass ratios, making them need more energy to maintain a constant temperature (they losee heat faster). They have more mitochondria PER CELL– small animals tissues are more metabolically active.

Question 17

Why does a mouse have the highest specific metabolic rate? What are the units of specific metabolic rate?

Answer 17

because it has the highest surface area to volume ratio.

units in ml O2/hr/gram

Question 18

In the model endotherm lab, why did the cylinder lose more heat than the sphere of a similar volume (mass)?

Answer 18

because it has a higher surface area :volume ratio. Required more energy input in order to stay the same temp as the sphere.

Question 19

As sphere mass increases, Sa/vol ratio _____, resulting in ____ in specific heat loss (MR)(heatloss/hr/g).

Answer 19

As sphere mass increases, Sa/vol ratio decreases, resulting in decrease in specific heat loss (heatloss/hr/g). Supposed theory that sa/vol ratio plays a role.

Question 20

the slope of a log mass (x axis) an log metabolic rate (heat loss on y axis) should be ___. Why?

Answer 20

should be positive. The larger the mass, the more heat the animal generally “loses” (ie/ see why fat people have higher basal metabolic rates), but smaller animals have higher SPECIFIC metabolic rates.

Question 21

According to the lab results, was core temperature maintenance or insulation better at maintaining temperatures when exposed to wind?

Answer 21

insulation was better. but moving out of the wind was best ;)

Question 22

What is a counter current exchange system? What species use this?

Answer 22

A system which utilizes parallel pipes/VESSELS of flowing fluid in opposite directions in order to save energy. hot fluid (blood) heats the colder fluid (blood), and the cold fluid cools down the warm one. The result is thermal equilibrium.

birds use a countercurrent heat exchanger between blood vessels in their legs to keep heat concentrated within their bodies

Question 23

physiological and behavioral strategies used to avoid cold stress

Answer 23

1) brown fat
2) shivering thermogenesis
3) topor: lower body temperature for certain amount of hours in a day to prevent energy loss (from motor activity)

4) hibernation; slows down metabolism.
5) huddle/curl into ball to minimize surface area:volume ratio.

6) insulation
7) core principle through VASOCONSTRICTION.

Question 24

why does fluffing hair help with insulation?

Answer 24

winter hair tends to be hollow, and fluffing hair puts a warm layer of air between skin and fur. layer.

Question 25

BEST method for preventing heat loss

Answer 25

getting out of the wind (go to still air)/ find shelter.

being inside is better than standing outside with a jacket (insulation)

Question 26

heat that comes off you is ___

Answer 26

radiation

Question 27

wind cools through

Answer 27

convection

Question 28

cooling by removing moisture

Answer 28

evaporation.

Question 29

what is torpor?

Answer 29

a lowering of body temperature for a prolonged period of time to prevent energy loss.

Question 30

the core principle operates on

Answer 30

vasoconstriction. constricting blood vessels to peripheral areas allows for warm blood to be concentrated in the core.

Question 31

in the thermoneutral zone, we rely on ____ and changes in ___ to maintain temperature.

Answer 31

we rely on INSULATION and changes in CIRCULATION to maintain temperatuer.

Question 32

at high temperatures, the body is in a zone of ___ ____ ___. What happens

Answer 32

zone of ACTIVE HEAT LOSS. sweating

Question 33

at low temperatures, the body is in a zone of ___ ___. What happens

Answer 33

zone of ACTIVE HAT GAIN. Metabolic regulation in endotherms occurs- speeds up to generate enough energy to maintain high internal temperatures (shivering thermogenesis, motor activity, fur fluffing).

Question 34

what is heat conduction

Answer 34

Heat conduction (or thermal conduction) is the movement of heat from one solid to another one that has different temperature when they are touching each other

Question 35

what is heat convection

Answer 35

Convection. When a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along.

ex/ hot air rises

Question 36

what is heat radiation

Answer 36

Radiation is a method of heat transfer that DOES NOT RELY ON CONTACT between the heat source and the heated objec