2. Thermoregulation

3. Thermoregulation
Process by which animals maintain an internal temperature within a tolerable range.
Critical to survival as biochemical & physiological processes are sensitive to changes in temperature (consider enzymatic reactions)

4. Before Viewing:
How are organisms adapted in hot climates? Cold?
Create a t-chart & list adaptations.
During Viewing:
Add adaptations (behavioural, morphological, physiological) to your t-chart.
Include specific examples (elephant, penguin)

5. Homeotherms
-maintain a stable internal temperature despite external temperatures. (mammals -including humans- and birds)

6. Poikilotherms - body temperature fluctuates with the environment
eg. Insects, reptile, fish

7. Endotherms- body temperature is maintained internally through chemical reaction
• Generally homeotherms are endotherms (not always)

8. Ectotherms- body temperature is maintained by external sources

9. What happens to the metabolic rates of ectotherms and endotherms as the environmental temperature changes?

11. Control
(room temp.)
Warm
(10o above)
Cool water
(10o below)
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Average
Purpose: To determine the effect that the environment has on metabolism of Daphnia.

12. Sketch the response of Daphnia’s metabolism to temperature
Sketch the response of Daphnia’s metabolism to temperature. (heart rate, water jumps,etc)
Based on the response of her metabolism to environmental temperature can you determine if Daphnia are homeotherms or poikilotherms? Explain.

13. Balancing Heat Loss and Gain
Insulation
Circulatory Adaptations
Cooling by Evaporative Heat Loss

14. Insulation Feathers, hair or fat layers
Reduces the flow of heat between an animal and its environment
Lowers the energy cost of keeping warm

15. In mammals, the insulating material is associated with skin and hair
Epidermis
Sweat
pore
Muscle
Dermis
Nerve
Sweat
gland
Hypodermis
Adipose tissue
Blood vessels
Oil gland

16. Most land animals and birds react to cold by raising their fur or feathers
Traps a thicker layer of air
Increasing its insulating power (the more still air = more insulation!)

17. Restricts air flow, creating a warmer boundary layer
Goosebumps
Raise hair on skin
Restricts air flow, creating a warmer boundary layer

18. Circulatory Adaptations
We can alter the amount of blood (heat) flowing between the body core and the skin.
Vasodilation
Increases the diameter of vessels = more blood
Increases heat transfer to surroundings.

19. Vasoconstriction
Reduced diameter of blood vessels = less blood
Reduces heat transfer
Keeps blood (and heat) in the interior of body

20. Evaporative Heat Loss when the environment is hotter than the body:
Sweat, pant, bathe, spread saliva over body surfaces
Heat is carried away with water molecules as they change into a gas

21. What regulates our temperature?
Hypothalamus - contains a group of nerve cells that function as a thermostat

22. What happens in response to heat stress in mammals?
body becomes warm (environment, exercise)
Thermoreceptors detects a change temperature
hypothalamus interprets an increase in temperature
skin blood vessels dilate sweat glands sweat
increase blood flow to skin evaporation = heat loss
heat lost through skin

23. On the previous chart, identify what is the sensor, integrator, and effector

24. What happens in response to cold stress in mammals?
body becomes cooler (environment, inactivity)
Thermoreceptors detects a change temperature
Hypothalamus detects decrease in temperature
blood vessels near skin constrict Skeletal muscles contract
decrease blood flow to skin Shiver response (heat) Hair stands up
heat is conserved

25. A. What is the difference between Topor
For Tuesday Know:
A. What is the difference between Topor
B. What is Osmoregulation? Read section 9.4
Make note of the following:
The importance of water balance
Osmoregulation
Why osmoregulation is tied to excretion
What molecules are excreted from mammals, fish, and birds.
Where these molecules originate