pa5tabear said:
Recently I saw an article about sled dogs burning 10,000 calories in a day. Even when adjusted for mass, this is significantly more energy than a human athlete might use.
This got me thinking: how much energy do bacteria use in a day? Trees? Fungi? Other animals?
I can think of lots of variables that will affect energy usage, but I still see no reason why the data couldn't be gathered/compared.
So far the only data I've seen is comparing sled dogs to humans, so please post anything you've seen along these lines.
I suspect your source is incorrect. Mass has to be corrected for by Kleiber's Law, not a linear relationship.
I don’t know what that “corrected for mass” means in this case. Maybe they mean that some dogs do better than what would be expected from Kleiber’s Law. However, I am not sure.
I suspect what you mean is that dogs do better than humans under the hypothesis that metabolism is linear to mass. However, this hypothesis is wrong. Metabolism generally follows Kleiber's Law. Metabolism is proportional to the 3/4 power of mass.
Metabolism generally scales with mass by Kleiber’s Law. Perhaps you could provide a reference, or tell us what the mass correction you are referring to means.
Kleiber’s Law is an empirical relationship. It describes how metabolism scales with mass in all organisms, including animals and plants. Of course there are deviations from it. However, the law works very well considering all the different organisms it covers.
A rigorous proof of Kleiber’s Law requires mathematics. However, the empirical demonstrations have been around a long time.
Here is a link which merely states the scaling law relating metabolism with mass as an empirical finding.
http://sciwrite.org/wp/wp-content/uploads/2011/05/PhsicsTodayArticle.pdf
“Life’s Universal Scaling Laws
Figure 1: The basal metabolic rate of mammals and birds was first plotted by Max Kleiber in 1932. In this reconstruction, the slope of the best straight line fit is 0.74,… “
See the plot, Figure 1, in the following link. It shows how the metabolism of different animals, including humans and dogs, scale with weight.
Sorry I have no link for the following reference. However, I have the book in my hand.
A physical explanation for the Kleiber’s Law is provided by Richard Dawkins in the following reference:
“The Ancestors Tale” by Richard Dawkins (Mariner Books, 2005) pp 510-514.
The chapter with the qualitative explanation for the scaling law is “The Cauliflower’s Tale”, which was written with Yan Wong. Kleiber's Law also applies to plants.
The physical explanation of Kleiber’s Law has to do with the supply problem that organisms have. Large organisms have a supply porblem. The blood systems in animals and the vascular tubing in vascular plants have to transport stuff to and from tissues. Small organisms don't face the same problem to the same extent. Somehow, this leads to Kleiber's Law.
The actual mathematical proof is not in the above reference, but a popularized distillation of the physical rule. The mathematical analysis was by biologists James Brown and Brian Enquist. I took this reference from Richard Dawkins
G. B. West, J. H. Brown, B. J. Enquist, “The origin of the universal scaling laws in biology. In Scaling in Biology. (Oxford University Press, 2000).
Also read:
"Newton Rules Biology" by C. J. Pennycuick (Oxford University Press, 1992).
It is a general treatment of scaling laws in biology.