Transcript Document
Current research on DEB theory Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam [email protected] http://www.bio.vu.nl/thb/ Lisboa, 2007/02/07 Current research on DEB theory Contents: • What is DEB theory? • Historical roots Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam [email protected] http://www.bio.vu.nl/thb/ • Scales in time & space • Empirical basis • Unexpected links • Applications of DEB theory Lisboa, 2007/02/07 Dynamic Energy Budget theory for metabolic organization • consists of a set of consistent and coherent assumptions • uses framework of general systems theory • links levels of organization scales in space and time: scale separation • quantitative; first principles only equivalent of theoretical physics • interplay between biology, mathematics, physics, chemistry, earth system sciences • fundamental to biology; many practical applications Historical 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 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 the 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 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 Models with many variables & parameters hardly contribute to insight time Standard DEB model Isomorph with 1 reserve & 1 structure feeds on 1 type of food has 3 life stages (embryo, juvenile, adult) Extensions: • more types of food and food qualities • more types of reserve (autotrophs) • more types of structure (organs, plants) • 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 1889 DEB theory is axiomatic, 1951 Huggett & Widdas Survival probability for aging based on mechanisms temperature dependence of Arrhenius 1951 Weibull physiological rates not meant to glue empirical models foetal growth survival probability for aging 1891 Huxley allometric growth of body parts 1955 Best diffusion limitation of uptake 1902 Henri Michaelis--Menten kinetics 1957 Smith embryonic respiration 1905 Blackman 1973 Droop reserve (cell quota) dynamics 1910 1920 Since many empirical models bilinear functional response microbial product formation 1959 Leudeking & Piret to binding be special cases of DEB theory Cooperative hyperbolic functional response Hill turn out 1959 Holling von Bertalanffy growth ofthese 1962 maintenance in yields of biomass behind models support DEB theory Pütter the data Marr & Pirt individuals 1927 Pearl 1928 Fisher & Tippitt 1932 Kleiber logistic population growth This makes DEB theory very tested against data Weibull aging water loss in bird eggs 1974 well Rahn & Ar respiration scales with body 3/ 4 1932 digestion 1975 Hungate DEB theory weight reveals when to expect deviations root growth of tumours development of salmonid embryos Mayneord 1977 Beer & Anderson from cube these empirical models 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 Applications of DEB theory Fundamental knowledge • bioproduction: agronomy, aquaculture, fisheries • pest control • biotechnology, sewage treatment, biodegradation • (eco)toxicology, pharmacology • medicine: cancer biology, obesity, nutrition biology • global change: biogeochemical climate modeling • conservation biology; biodiversity • economy; sustainable development of metabolic organisation has many practical applications 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 38 participants in 2007 Late registration via [email protected] Slides of this presentation will be downloadable from http://www.bio.vu.nl/thb/users/bas/lectures/ Audience: thank you for your attention