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Bas Kooijman
Department of Theoretical Biology, VU University Amsterdam |
Amsterdam, The Netherlands
bas.kooijman@vu.nl
Metabolic dynamics: acceleration during the life cycle
of an individual
The life cycle of a typical multicellular organism has an embryo phase, which does not eat, a juvenile, which does not allocate to reproduction and an adult. Quantitative knowledge of this life cycle is key to population and ecosystem dynamics. Modelling the cycle requires the notion of metabolic memory as state variable of the individual conceived as a dynamical system, since an embryo grows, but does not eat. An egg (or seed) is energetically isolated from its environment; foetal development is a variation on this scheme.
To my knowledge, the Dynamic Energy Budget (DEB) model is the only one that can capture this full cycle. It has been applied to data on a wide variety of aspects of energetics of over 200 animal species in the add_my_pet collection; its goodness of fit is typically very high. Although the amount of data varies a lot among species, all parameters could be estimated using the covariation method.
A first observation on the add_my_pet collection is that a single set of parameter values actually captures the full cycle for many species. So the parameter values remain constant over the stage transitions, despite impressive morphological changes. This is remarkable, because DEB theory is based on simple physical and chemical principles and not aimed to be descriptive.
A second observation is that particular taxonomic groups seem to accelerate their metabolism temporarily during the cycle. Such an observation is only possible after having an quantitative expectation for the cycle without acceleration. I will discuss the various acceleration patterns and mechanisms, and discuss how acceleration turns out to be linked to other features of the life cycle.
References:
A general intro to DEB theory:
http://www.bio.vu.nl/thb/research/bib/Kooy2012.pdf
Add_my_pet in the electronic DEB laboratory:
http://www.bio.vu.nl/thb/deb/deblab
Covariation method for parameter estimation
http://www.bio.vu.nl/thb/research/bib/LikaKear2011.html
Metabolic acceleration:
http://www.bio.vu.nl/thb/research/bib/KooyPecq2011.html
http://www.bio.vu.nl/thb/research/bib/Kooy2012b.html
Join the DEB tele course 2013 for free
http://www.bio.vu.nl/thb/deb/course/