Evolution in the context of DEB theory Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam Bas@bio.vu.nl http://www.bio.vu.nl/thb/ Wimereu, 2011/06/14

Mouse goes preying 2.1c On the island Gough, the house mouse Mus musculus preys on chicks of seabirds, Tristan albatross Diomedea dabbenena Atlantic petrel Pterodroma incerta The bird weights are 250  the mouse weight of 40 g, Mice typically weigh 15 g 99% of these bird species breed on Gough and are now threatened with extinction

Dwarfing in Platyrrhini 8.1.2 Cebidae 130 g Saimiri 200-400 g Saguinus 400-535 g 480-700 g 400-450 g 780-1250 g 700-1000 g 3500 g Callimico Callitrix Evolutionary dwarfing occurred within the Cebidae where new groups splitted off of smaller body size and larger distance to center-Amazonia. Cebus, Saimiri and Aotus are relatively big and occur in center-Amazonia Saguinus, Leontopithecus and Callimico split off, are smaller and occur at the border of center Amazonia Callithrix, Mico and Cebuella followed, are even smaller and outside center Amazonia on the slopes of the Andes This dwarfing is supposed to be related to food availability. DEB theory suggests the same explanation for Bergmann’s rule that max body size in a taxon increases from the equator to the poles. Bergmann’s rule does not apply here, but DEB’s explanation does. Cebuella Leontopithecus MYA Mico Aotus 24.8 20.2 Perelman et al 2011 Plos Genetics 7, 3, e1001342 Cebus

Altricial & Precocial Finfoots 2.5.2e Heliornis fulica American finfoot Podica senegalensis, African finfoot Heliopais personata, Asian finfoot Most bird-families are either altricial or precocial, but the 3-species family of finfoots (Heliornithidae) have both. This illustrates the evolutionary adaptability of the trait. African and Asian finfoots are precocial, but American finfoots (also called sungrebes) are born altricial, blind without feathers. The male sungrebe (lower left) has a pouch under each wing, in which he can carry the young, even in flight; they typically have 3 or 4 young. Sungrebes have an very short incubation time for their size (130 g) of 10 – 11 days; both sexes share breeding in a nest in the vegetation above water. The eggs are 28  20 mm, so they weigh about 6 g. In African finfoots (338 – 879 g) only the females breeds her 2 eggs; the young leave the nest after a few days. Finfoots resemble grebes and can also dive very well, but don’t do that for collecting food, which is a variety of insects, spiders, molluscs, fish, frogs etc.

Central Metabolism 3.8.2b source polymers monomers waste/source

Evolution of central metabolism 10.2.1 in prokaryotes (= bacteria) 3.8 Ga 2.7 Ga i = inverse ACS = acetyl-CoA Synthase pathway PP = Pentose Phosphate cycle TCA = TriCarboxylic Acid cycle RC = Respiratory Chain Gly = Glycolysis Kooijman, Hengeveld 2005

Evolution of DEB systems 10.3 variable structure composition strong homeostasis for structure internalisation of maintenance as demand process delay of use of internal substrates increase of maintenance costs installation of maturation program 1 2 3 4 5 6 prokaryotes 7 9 plants This scheme presents an evolutionary scenario for the metabolic organisation of an individual. Only 2 of several reserves are shown. Stacked dots (upper left) represent sloppy coupling between the various structural components 1: originally, strong homeostasis hardly applied and the various compounds from structure where formed from substrates, possibly will little transformation 2: the development of homeostasis comes with stoichiometric constraints on the uptake of substrates 3: since growth can only occur if all required substrates are present, and substrate concentrations vary in time, reserves develop, originally by delaying the processing of internalised substrates. 4: the increase of efficiency of protein-mediated substrate uptake involves maintenance costs. The increased uptake efficiency increases the reserve pools, and the necessity developed to convert and store reserve (in polymers, or nutrients in vacuoles) 5: since substrates vary in concentration and are continuously required for maintenance, the payment of maintenance is internalised and done from mobilised reserve 6: size control comes with a need for a maturation program; defense systems are fuelled from maturity maintenance Under starvation conditions, where maturity maintenance cannot be paid, rejuvenation occurs, and the hazard rate is increased. Failure of paying somatic maintenance leads to shrinking of structure, but is a threshold is exceeded, death is instantaneous. This situation applies to modern bacteria and many protoctists 7: The animal-line of development, which feed on other organisms, increased homeostasis and the number of reserves shrinks to 1. 8: Reproduction evolved and the juvenile stage gave rise to an embryo (no assimilation) and an adult stage (no maturation, but reproduction) 9: The plant-line of development increased the number of structures (roots and shoots), with specialised assimilation tasks Reproduction evolved also here, typically in the shoot, and translocation evolved: a fraction of mobilised reserve is allocated to the other structure. 8 animals Kooijman & Troost 2007 Biol Rev, 82, 1-30 reproduction juvenile  embryo + adult strong homeostasis for reserve specialization of structure

Evolution of DEB systems 10.3a Start: variable biomass composition, passive uptake Strong homeostasis  stoichiometric constraints Reserves: delay of use of internalised substrates  storage, weak homeostasis Maintenance requirements: turnover (e.g. active uptake by carriers), regulation Maintenance from reserve instead of substrate; increase reserve capacity Control of morphology via maturation; -rule  cell cycle Diversification of assimilation (litho-  photo-  heterotrophy) Eukaryotisation: heterotrophic start; unique event? Syntrophy & compartmentalisation: mitochondria, genome reorganisation Phagocytosis, plastids (acquisition of phototrophy) Animal trajectory: biotrophy Reduction of number of reserves Emergence of life stages Further increase of maintenance costs Further increase of reserve capacity Socialisation Supply  demand systems Plant trajectory: site fixation Differentiation of root and shoot Emergence of life stages Increase of metabolic flexibility (draught) Nutrient acquisition via transpiration Symbioses with animals, fungi, bacteria (e.g. re-mineralisation leaf litter, pollination)

Symbiogenesis 10.4g 2.7 Ga 2.1 Ga 1.27 Ga phagocytosis

Symbiogenesis 10.4p symbioses: fundamental organisation of life based on syntrophy ranges from weak to strong interactions; basis of biodiversity symbiogenesis: evolution of eukaryotes (mitochondria, plastids) DEB model is closed under symbiogenesis: it is possible to model symbiogenesis of two initially independently living populations that follow the DEB rules by incremental changes of parameter values such that a single population emerges that again follows the DEB rules essential property for models that apply to all organisms Kooijman, Auger, Poggiale, Kooi 2003 Quantitative steps in symbiogenesis and the evolution of homeostasis Biological Reviews 78: 435 - 463

Symbiosis 10.4m substrate product Very few life forms can exist without the help of other life forms. Mutual syntrophy, the you of pruducts as substrates dominates co-existence at all levels of organisation. Think of the interaction between metabolic modules within a unicellular, between organs in a multicelluar, between individuals or populations.

Symbiosis 10.4n substrate substrate The use each other products affects the role of the original substrate. Stoichiometric coupling between the use of substrate and product is an important route to homeostasis: the ability to run metabolism independently from environmental conditions (less than perfect, of course)

Steps in symbiogenesis 10.4o Free-living, homogeneous Free-living, clustering Internalization The rules of DEB theory allow for a unique property: individuals that follow DEB-rules can merge to a new single individual incrementally such that the merge individual again follows the DEB rules. An individual can also split up this way. Merging and splitting have been frequent in evolution. This metabolic flexibility is possible due to basic simplicity in the organisation. Rules for Synthesising Unit (SU) dynamics play an important role here: SUs are generalised enzymes that follow the rules of enzyme kinetics with 2 modifications: 1) transformation is not controlled by substrate concentrations, but the arrival rates of substrate molecules to SUs 2) intra-cellular transport processes prevent the conversion of products to substrates; the transformation from substrates to products is unidirectional The processes of merging and splitting imposes constraints of organisation. This has similarities for firms as an individual in economy. A group in Lisbon is exploring the interrelationships between biological and economics systems in the context of DEB theory. Structures merge Reserves merge

Syntrophy 9.1.2 Coupling hydrogen & methane production energy generation aspect at aerobic/anaerobic interface ethanol acetate dihydrogen dihydrogen bicarbonate methane Total: methane hydrates >300 m deep, < 8C linked with nutrient supply

Allocation to soma 10.5.2 Frequency distribution of κ pop growth rate, d-1 max reprod rate, #d-1 survivor function κ κ κ Frequency distribution of κ among species in the add_my_pet collection: Mean κ = 0.75, but optimum is κ = 0.5 Lika et al 2011 J. Sea Res, to appear