Ir. Mrs T. A. (Tineke) Troost

Room: T551
Phone: 020-5987246
Curriculum vitae
Specialization: Mathematical Biology
Project: Self-organisation of community metabolism

Self organisation of community metabolism


All around us, areas of land and volumes of water contain assemblages of different species, in different proportions and doing different things. An important property of such communities is that the species interact. Together they form very complex food webs, with plants, herbivores, detritivores and carnivores.

Naturally, the precise type of communities that arise depend on their environment they live in, but equally important is the feedback from the communities on the environment. Together, a community and its environment are called an ecosystem.

The phenomenons of `ecosystem' and `food web' give rise to many questions:

Aim of study

In this project the 'evolution' of ecosystems is studied. Objective is to get more insight in the organization of species into food webs. Also we study the coupling between function and structure in biological communities.

Evolution: from a
single-species community to a complete foodweb

Evolution: from a single-species community to a complete foodweb


In this project we try to make a model that is capable of organizing itself in simple food webs.

  1. We start with a model from a single-species community of mixotrophs. Mixotrophs can use energy of both organic and inorganic sources, and are thus completely selfsufficient. Evolution is added to the model in the form of small and random mutations, which will give the system freedom to go in several ways and will thus make self-organization possible.
  2. Then we will study the specialisation of the mixotrophs into separate heterotrophs and autotrophs. Heterotrophs and autotrophs are mutually dependend on each other and thus will have to form a very simple food web in order to survive.
  3. From there on we will extend the model with detritivores and carnivores, to achieve more complex and realistic food webs. These food webs, in combination with the body size scaling relationships already present in the models, will enable us to study the coupling between function and structure in biological communities.

We will try to model this whole process of self organization by combining two existing theories (Dynamic Energy Budget and Adaptive Dynamics). AD is used to quantify adaptation and speciation in organisms, DEB specifies general rules for uptake and use of substrates in organims. A short description of both theories is given below.

Adaptive Dynamics: The theory on Adaptive Dynamics (AD) is about quantitative changes at an evolutionary time scale in characteristics of species, as described by parameter values. These characteristics include rules for the (sloppy) heredity of parameter values in parent-offspring transitions. The theory can predict under what circumstances the scatter distribution of individual-specific parameters values breaks up, a process that corresponds with speciation.

Dynamic Energy Budget: The Dynamic Energy Budget Theory (DEB) is a general framework for modeling organisms, which links different levels of biological organisation (cells, organisms and populations). The theory presents simple mechanistic rules that describe the uptake and use of energy and nutrients (substrates, food, light) and the consequences for physiological organisation throughout an organism's life cycle.

This is the symposium that concludes my project: