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Current research on DEB theory Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam [email protected] http://www.bio.vu.nl/thb/ Marseille, 2007/01/17 Historic roots Aug 1979 Two questions: • How should we quantify effects of chemical compounds on reproduction of daphnids? reproduction energy budget • How bad is it for the environment if daphnid reproduction is a bit reduced due to toxic stress? individual population ecosystem prediction outside observed range: first principles Modes of action of toxicants 6.4 assimilation food maintenance costs defecation feeding faeces growth costs assimilation reproduction costs reserve somatic maintenance maint 1- 7 growth structure u tumour 6 hazard to embryo maturity maintenance maturation reproduction maturity offspring 6 tumour induction 7 endocr. disruption 8 lethal effects: hazard rate Mode of action affects translation to pop level Individual Ecosystem • population dynamics is derived from properties of individuals + interactions between them • evolution according to Darwin: variation between individuals + selection • material and energy balances: most easy for individuals • individuals are survival machines of life DEB – ontogeny - IBM 1980 Daphnia ecotox embryos application body size scaling epidemiol applications morph dynamics indirect calorimetry micro’s food chains 1990 NECs DEBtox 1 Synthesizing Units multivar plants 2000 tumour induction organ adaptation function ISO/OECD bifurcation analysis numerical methods Global bif-analysis aging DEB 1 DEB 2 von Foerster molecular organisation ecosystem dynamics integral formulations adaptive dynamics symbioses ecosystem Self-orginazation Shift in emphasis From concrete questions about individuals quantification of properties of individuals + consequences To metabolic organisation at various levels relationships between levels of organisation Space-time scales 1.2.1 space Each process has its characteristic domain of space-time scales system earth ecosystem population individual cell molecule When changing the space-time scale, new processes will become important other will become less important Individuals are special because of straightforward energy/mass balances time Dynamic Energy Budget theory for metabolic organization • links levels of organization molecules, cells, individuals, populations, ecosystems scales in space and time: scale separation • interplay between biology, mathematics, physics, chemistry, earth system sciences • framework of general systems theory • quantitative; first principles only equivalent of theoretical physics • fundamental to biology; many practical applications (bio)production, medicine, (eco)toxicity, climate change Standard DEB model Isomorph with 1 reserve and 1 structure that feeds of 1 type of food and has 3 life stages (embryo, juvenile, adult) Extensions: • more types of food and food qualities • more types of reserve • more types of structure • changes in morphology • different number of life stages Empirical special cases of DEB year author model year author model 1780 Lavoisier multiple regression of heat against mineral fluxes 1950 Emerson cube root growth of bacterial colonies 1825 Gompertz Survival probability for aging 1951 Huggett & Widdas foetal growth 1889 Arrhenius 1902 temperature dependence of DEB theory is rates axiomatic, 1951 Weibull physiological allometric of body parts Huxleybased 1955 Best on growth mechanisms Michaelis--Menten kinetics empirical Henri not meant 1957 Smith to glue models 1905 Blackman 1910 Hill 1891 1920 1927 bilinear functional response 1959 Leudeking & Piret survival probability for aging diffusion limitation of uptake embryonic respiration microbial product formation Cooperative binding hyperbolic functional response 1959 Holling Since many empirical models von Bertalanffy growth of maintenance in yields of biomass Pütter 1962 Marr & Pirt individuals turn out to be special cases of DEB theory logistic population growth reserve (cell quota) dynamics Pearl Droop the data behind these 1973 models support DEB theory 1928 Fisher & Tippitt 1932 Kleiber Weibull aging 1974 Rahn & Ar water loss in bird eggs This makes theory very tested against data respirationDEB scales with body digestion 1975 well Hungate weight3/ 4 1932 Mayneord cube root growth of tumours 1977 Beer & Anderson development of salmonid embryos Daphnia Length, mm 1/yield, mmol glucose/ mg cells O2 consumption, μl/h DEB theory reveals unexpected links Streptococcus 1/spec growth rate, 1/h respiration length in individual animals & yield growth in pop of prokaryotes have a lot in common, as revealed by DEB theory Reserve plays an important role in both relationships, but you need DEB theory to see why and how DEB tele course 2007 Cambridge Univ Press 2000 http://www.bio.vu.nl/thb/deb/ Free of financial costs; some 200 h effort investment Feb-April 2007; target audience: PhD students We encourage participation in groups that organize local meetings weekly Participants of DEB tele course 2005 created AQUAdeb: special issue of J. Sea Res. 2006 on DEB applications to bivalves Software package DEBtool for Octave/ Matlab freely downloadable Slides of this presentation will be downloadable from http://www.bio.vu.nl/thb/users/bas/lectures/ Audience: thank you for your attention