LECTURE 15: PHYSIOLOGICAL ECOLOGY

Question 1

Physiological ecology

Answer 1

The study of the physiologies of organisms with respect to their ecological environments

Question 2

Biodiversity is more than just the amount of species living in a given area…

Answer 2

It is the combination of morphologies, physiologies and behaviors

Question 3

Physiology

Answer 3

the functions of the structures of different organisms and how organisms acquire energy

Question 4

Core concepts in ecophysiology

Answer 4

• ranges of tolerance
• organisms are complex chemical reactions
• reactions occur at optimal temperatures as well as osmotic conditions
• many mechanisms for homeostasis have evolved for suitability in complex environments
• maintenance of homeostasis requires a lot of energy and is managed by tradeoffs and constraints

Question 5

Organisms in similar environments…

Answer 5

have similar solutions to their environments (physiologies, morphologies, and behaviours) especially because of convergent evolution

Question 6

How are an organism’s tolerance levels tested?

Answer 6

We look at their critical temperatures - the point to which they begin to lose certain functions

Question 7

Thermal tolerance breadth

Answer 7

Number of degrees between maximum and minimum temperature than an organism can withstand

Question 8

Why do organisms from equatorial regions have lower thermal tolerance breaths?

Answer 8

Due to the fact that there is not great variation in seasonality at the equator, the ability of a large thermal temperature is not required

Question 9

Poikilotherms

Answer 9

• cold blooded animals that don’t have the internal processes to regulate a certain temperature but rather do so in behavioural mannerisms

Question 10

Homeotherms

Answer 10

• warm-blooded organisms
• critical to make sure that they have the right range of temperature in their body to ensure adequate survival and living conditions

Question 11

Modes of heat loss or gain

Answer 11

1. Radiation: electromagnetic radiation
2. Conduction: heat transfer between the touching of two objects
3. Convection: Heat transfer through liquid mediums (gas and air)
4. Evaporation
5. Redistribution : moving heat from one place to another

Question 12

Why does size matter for heat balance?

Answer 12

• SA/V ratio
• High SA/V: smaller animal and thus more prone to losing heat to the environment
• Smaller SA/V: larger animal; greater ability to retain heat

Question 13

Surface Area Provides..

Answer 13

rate of equilibrium (to environment)

Question 14

Volume provides…

Answer 14

inertia

Question 15

Bergmann’s rule: size matters

Answer 15

Homeotherms tends to be larger and thus have a smaller surface area to volume ratio due to their need to retain the heat from their environment

Question 16

Animal with a maximum SA/V ratio

Answer 16

chrysopelen gliding snake (found in warm tropical water)

Question 17

Animal with minimum SA/ V ratio

Answer 17

american pika (lives in extremely cold environment)

Question 18

Allen’s rule

Answer 18

Shape of appendages also corresponds with an organism’s ability to retain heat
- homeotherms have smaller appendages at higher latitudes as appendages and their increasing size correspond to loss of heat

Question 19

Countercurrent circulation

Answer 19

• veins return blood from the appendages to core while arteries take the blood from the core to the appendages
• if arteries and veins are very close together, it keeps the blood warm near the core as heat transfers from arteries to veins so that the blood return to the core is also warm
• veins are designed in a way so that no heat is actually lost through this process
• concentration temperature gradient

Question 20

Weasels

Answer 20

• lives in extremely cold climates
• however, have considerably large appendage (tail) and SA/V ratio which would be more suitable for an organism in a lower latitude climate
• this is counterintuitive but makes sense with regard to their prey
• prey live in burrows which they will need to get into
• thus haVing the tendency to lose heat (cost) is balanced oUt with the predatory efficiency of this organism (benefit)
• TRADEOFF FOR BETTER PREDATION SUCCESS

Question 21

tradeoff

Answer 21

being good at x means you can be bad at y

Question 22

constraint

Answer 22

Adaptations work with what variation is available in the population at the time
- thus imperfect design because you have to work with what is available for you to use

Question 23

Vascularization in appendages

Answer 23

Enables organisms to be better at losing heat to the environment; typical in homeotherms that live in extremely warm environments