Chapter 32 - Body Temperature (part 3)

Question 1

How do animals keep their body temperature within acceptable limits despite outside temperatures?

Answer 1

Thermoregulatory strategies

Question 2

What are some conditions do organisms face in environmental conditions?

Answer 2

1. temperature
2. water availability
3. salt/ion availability

Question 3

What are the two strategies to animals use to deal with environmental variability?

Answer 3

1. conforming
2. regulating

Question 4

What does is mean to be “conforming” ?

Answer 4

an animal’s body temperature that conforms with changes in the environment.

Question 5

What does it mean to be “regulating” ?

Answer 5

their temperatures stay the same regardless of the outside environment

Question 6

What is homeostasis?

Answer 6

the maintenance of a steady state despite internal and external changes
want to be in balance, in equilibrium

Question 7

What is thermoregulation?

Answer 7

control of body temperature within an acceptable range around an ideal set point.

Question 8

What happens when an organism is outside of thermoregulation?

Answer 8

1. reduced efficiency of enzymes
2. altered fluidity of cell membranes
3. unacceptable speed of temperature sensitive biochemical processes
4. reduces performance/fitness
5. can be fatal

Question 9

In one sentence, describe what thermoregulation is all about.

Answer 9

balancing heat loss AND
heat gain

Question 10

What are the two sources of heat that animals have?

Answer 10

1. internally - generated
2. external sources

Question 11

What is internally-generated heat?

Answer 11

its via cell respiration aka metabolism
endothermy

Question 12

What are external sources of heat?

Answer 12

sun either directly or indirectly
ectothermy

Question 13

give an example of an animal using both heat sources

Answer 13

manatees in Florida swim toward areas that are warmer during the winter

Question 14

How do some fast moving fishes keep warm and what is this referred as?

Answer 14

1. they generate extra body heat in cold water to keep the important tissue warm
2. this is regional endothermy

Question 15

What are the trade offs of endothermy? (pro vs con)

Answer 15

Pro- can generate enough heat to main a high core body temp in cold env.
Con - metabolically expensive so it must consume way more food than an ectotherm of the same size

Question 16

What are the trade offs of ectothermy?

Answer 16

Pro - metabolically economical - can consume less food and can do well where food supplies are limited
Con - body temperature depends on the outside temperature. are sluggish in cold env.

Question 17

what does endothermic mean?

Answer 17

organisms that are warmed by heat generated in their own metabolism (a stable body temperature
- birds and mammals

Question 18

What does ectothermic mean?

Answer 18

organisms in which external sources provide most of the heat for temperature regulation
- reptiles

Question 19

Why are endotherms “better” at inhabiting more environmental niches?

Answer 19

because they are not attached to the external environment’s temperature like birds and mammals so they can live in both hot and cold environments

Question 20

Where is Earth’s greatest biodiversity at?

Answer 20

the equator where ectotherms thrive

Question 21

What are the 4 avenues of heat exchange (aka thermoregulation) ?

Answer 21

1. convection
2. radiation
3. conduction
4. evaporation

Question 22

What is convection and give an example

Answer 22

• is the transfer of heat by the movement of air or water past a surface
  ex: wind takes the heat away from you - you get goose bumps
  cold water current moves past you - you get cold takes the heat with it

Question 23

What is radiation and give an example

Answer 23

• emission of waves by all objects warmer than zero
  ex: sun bathing

Question 24

what is conduction and give an example

Answer 24

• transfer of heat between molecules of objects in contact with each other
  ex: sitting in a warm seat (butt transferred that heat and some is coming back)

Question 25

What is evaporation and give an example

Answer 25

• removal of heat from the surface of liquid that is losing some of its molecules as a gas.
  ex: sweat - it takes the heat with it once it evaporates

Question 26

What are thermal windows? give an example

Answer 26

surfaces across which heat can easily escape
ex: open/close them like eyes, ears, mouth, skin

Question 27

What is thermal gradient?

Answer 27

• temperature difference between outside temperature and various surfaces of the animals
• the direction of heat exchange (in vs out) and the magnitude of it depends on thermal gradient

Question 28

When animals want to maximize heat loss, they can ___ the gradient.

Answer 28

increase aka excessive heat…too hot

Question 29

When animals want to minimize heat loss, they can ___ the gradient.

Answer 29

decrease aka too cold

Question 30

What is the most physiologically fast mechanism (in regards to heat balance) ?

Answer 30

adjusting blood flow

Question 31

What are two ways animals adjust blood flow?

Answer 31

1. Vascular shunting
2. vascular perfusion

Question 32

What is vascular shunting?

Answer 32

when cold, move hot blood away from thermal windows

Question 33

what is vascular perfusion?

Answer 33

when hot, move hot blood towards thermal windows
ex- when exercising face gets red, blood is moving towards the active muscles working

Question 34

What is the most physiologically long- term mechanism (in regards to heat balance) ?

Answer 34

Acclimatization
seasonal!

Question 35

What is acclimatization?

Answer 35

a process in which an individual adjusts to a change in its environment, allowing it to maintain fitness across a range of environmental conditions

Question 36

Give an example of acclimatization:

Answer 36

In endotherms - more feathers, thicker coat, us humans by more layers on, insulation is key
in ectotherms - adjust at the cellular level (so antifreeze proteins, enzymes)

Question 37

Hypothalamus act as a what?

Answer 37

a thermostat
- wants it to get back in balance when either too hot or too cold