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What mechanisms do warm-blooded animals have for generating heat that cold-blooded animals do not? By Stella Angeli Background taken from:

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Presentation on theme: "What mechanisms do warm-blooded animals have for generating heat that cold-blooded animals do not? By Stella Angeli Background taken from:"— Presentation transcript:

1 What mechanisms do warm-blooded animals have for generating heat that cold-blooded animals do not? By Stella Angeli Background taken from: http://userwww.sfsu.edu/~infoarts/cdmain/Tele/competency/elephant.jpg, http://farm4.static.flickr.com/3001/2631251051_5d36b95788.jpg?v=0

2 Warm-blooded and cold-blooded animals Warm-blooded animals keep their body temperature at a constant level in environmental changes by homeostatic mechanisms o Mammals o Birds Cold-blooded animals have their body temperature regulated by interaction with the environment o Reptiles o Insects o Arachnids o Amphibians o Fish Pictures taken from:http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/coldwarm.html, http://news.softpedia.com/images/news2/Cold-Blooded-Animals-Have- Larger-Offspring-in-Colder-Climate-2.jpg

3 Mechanisms for generating heat in warm-blooded animals Larger number of mitochondria per cell Larger number of mitochondria per cell – Able to generate heat by increasing the rate at which they burn fats and sugar – Greater quantity of food in order to replace the fat and sugar reserves Picture taken from:http://www.disaboom.com/photos/storage/1000.29381.44443.MitochondriaSMALL2.jpg Background taken from:http://www.jigcardgallery.com/JigCard/icaPuzStore/Mammals2Part1.jpg

4 Mechanisms for generating heat cont. Blood vessels in lower legs-heat exchangers (e.g. birds) Blood vessels in lower legs-heat exchangers (e.g. birds) -Veins are close to arteries, extract heat from them - Causes friction that produces heat Heat is spread in the body and escapes through the skin Picture taken from:http://openlearn.open.ac.uk/file.php/2314/S204_1_010i.jpg

5 Mechanisms for generating heat cont. Vasoconstriction Vasoconstriction -Blood vessels close to the skin surface become constricted -Smaller surface area for heat to be lost Minimal heat loss occours Shivering Shivering -Muscle contraction around vital organs -Cell respiration Heat is produced by using energy Pictures taken from: http://www.biosbcc.net/doohan/sample/images/CO%20and%20MAP/VasTone.jpg,http://www.illustrationsof.com/images/clipart/xsmall2/2414_shivering_polar_bear_tryin g_to_warm_up_beside_a_campfire.jpg

6 Mechanisms for generating heat cont. Insulation Insulation -Adipose tissue(marine mammals):  forms a thick layer of blubber Thermal insulation -Feathers and fur( birds, mammals):  trap a layer of air next to the skin Heat flow is reduced between the animal’s skin and the outside Each feather has an individual muscle that allows it to be lifted away from the body regulation of heat loss by changing the thickness of the air layer trapped among the feathers Fur contains hair close to the skin underneath thicker and larger surface hairs longer hairs – better insulation Pictures are taken from: http://marinebio.org/upload/_04/Hydrurga_leptonyx8.jpg,http://www.cartage.org.lb/en/themes/Sciences/Zoology/Biologicaldiverstity/AnimalsIII/featherstruct.gif

7 Cold-Blooded animals Mechanisms for generating heat Mechanisms for generating heat -Snakes and Lizards sunning themselves on rocks. -Fish changing depths in the water column to find a suitable temperature. -Desert animals burrowing beneath the sand during the day. -Insects warm their flight muscles by vibrating them in place. Pictures taken from: http://curiousanimals.net/wp-content/uploads/2007/06/632604567-b5ba885b80-m-small.jpg, http://www.vegsoc.org/fish/images/single-fish.jpg

8 Summary Warm-blooded animals generate heat by:  Having larger number of mitochondria per cell  Blood vessels in lower legs  Vasoconstriction  Shivering  Insulation (adipose tissue, feathers and fur) Cold-blooded animals have different mechanisms for generating heat (sunning on rocks, burrow under the sand, muscle vibration etc.)

9 References Articles Anissimov M., Wise GEEK, What is the Difference Between Warm-Blooded and Cold-Blooded Animals?, 2003-2009 Watanabe M., Bioscience, Generating Heat: New Twists in the Evolution of Endothermy,2005.55(6):470-475 WebPages http://en.wikipedia.org/wiki/Warm-blooded http://en.wikipedia.org/wiki/Cold-blooded http://openlearn.open.ac.uk/ http://en.wikipedia.org/wiki/Shivering http://www.compulink.co.uk/~argus/Dreambio/homeostasis/ectotherms% 20and%20endotherms.htm http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/coldwarm.html


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