Thermal Relations

Question 1

How does temperature influence the activities
of bumblebees?

Answer 1

It shivers to keep warm, but the temperature must be warm enough for the bumblebees to move their muscles.

Question 2

homeothermic

Answer 2

has an active and a preferred temperature

Question 3

What is the difference between temperature
and heat

Answer 3

• Temperature is the measure of intensity of
  random motion of atoms or molecules
  – Range of most life -2 to 50 o C
  
  • Pompeii worm (22o C head, 80o C tail)
• Heat is molecular kinetic energy
  – Depends on number of atoms and molecules
  as well as speed of atoms and molecules

Question 4

Physiological Importance of Temp vs. Heat

Answer 4

• Heat moves by conduction and convection
  from high temp to low temp
  – Down a temperature gradient
• Transfer of heat raises temperature of object
  gaining heat and vice versa
• No net transfer of heat if both objects have the
  same temperature

Question 5

Conduction

Answer 5

– Transfer of heat through substance that is
macroscopically motionless: rock
* So how can organisms maximize conduction?
– Increase the temperature gradient
– Decrease the distance between objects

Question 6

Convection

Answer 6

– Transfer of heat through substance by
macroscopic motion: water, wind
So how can you maximize convection?
– Maximize the gradient difference

Question 7

Radiation

Answer 7

– Transfer of electromagnetic radiation: long
distance, energy may be reflected, absorbed, or
transmitted; no direct contact between objects

Question 8

Evaporation

Answer 8

– Energy required change liquid to gas

Question 9

Heat storage

Answer 9

The smaller the surface area to
volume ratio, the more slowly heat is absorbed
and dissipated

Question 10

Three factors influence heat storage

Answer 10

1. Surface area
   – larger animals take up heat more slowly than
   smaller animals, also lose heat more slowly
2. Temperature gradient
   – the larger the temperature difference between
   an animal and its surrounding environment, the
   larger the temperature gradient
3. Specific heat conductance
   – High heat conductance
   * Tb usually very close to ambient
   – Low heat conductance
   * Tb constant
   – Typically possess insulation (e.g.
   feathers, fur, blubber) which reduces
   the temperature gradient

Question 11

Mechanisms of heat exchange between an organism and its environment

Answer 11

Radiation from the sky, direct radiation from the sun, reflected radiation from the sun, wind, convection, radiation from bush, radiation from animal, respiratory evaporation, cutaneous evaporation, radiation from ground, and conduction. all centered around the animal’s metabolic heat production

Question 12

Temperature classification of animals (based on
body temperature, Tb)

Answer 12

– Poikilotherms
* Animals in which the Tb fluctuates
* Tb is close to ambient temperature
– Homeotherms
* Animals that are capable of maintaining Tb
above or below ambient temperatures
– Remain active in both cold and warm
surroundings
* Regulate Tb within a narrow range

Question 13

Temperature classification of animals (based on the
source of stored heat in the body)

Answer 13

– Ectotherm
* Animals that rely on environmental sources of
heat
– Endotherm
* Animals that generate their own body heat
through metabolism
– Heterotherm
* Animals that are capable of some endothermic
heat production but do not regulate their Tb within
a narrow range
– Tb may be tightly monitored

Question 14

Two types of heterotherms

Answer 14

– Regional heterotherm
* Animals that maintain regions or parts of
their bodies above ambient temperatures
* Able to raise their core temperatures via
muscular activity (e.g. large fish, some flying
insects)
– Temporal heterotherms
* Body temperatures vary widely over time
(e.g. hibernating mammals or birds that
experience torpor)

Question 15

note

Answer 15

study the Categories of thermal relations in animals slide on d2l