Biology Reference
In-Depth Information
1.
INTRODUCTION
We model to explain observations, aspects of complex systems. Modelling
is necessarily an abstraction, that is, a reduction of complex interrelations to
essential features, without loosing the ability to predict. Figure 1 illustrates the
predictive power of abstract modelling using the drawing of a bird. Despite its
simplicity, this drawing allows us to identify/predict a real male lapwing if we
see one. There are various possibilities to improve this model: using a finer
pen, showing feathers, depicting the bird in flight etc. The message is that there
is no correct or wrong model but models with different purposes, models that
address different aspects of a complex system and that have different accuracies.
Mathematical modelling in systems biology is the art of making appropriate
assumptions, thereby choosing an appropriate level of abstraction. Mathematics
is the art that makes us realise reality, and as Picasso commented, art is a lie
that makes us realise truth.
The original conception of systems biology as a merger of control theory and
molecular and cell biology has as its central dogma the observation that it is
system dynamics and organising principles that give rise to the functioning and
function of cells (Wolkenhauer & Mesarovic, 2005). Cell function, including
growth, differentiation, division and apoptosis, are temporal processes and we
will only be able to understand them if we model them as dynamic systems.
While the areas of genomics and bioinformatics are identifying, cataloguing and
characterising the components that make up a cell, systems biology focuses on an
understanding of functional activity from a systems perspective. The biological
agenda of systems biology can subsequently be defined by the following two
Figure 1
This is not a bird - it is a model of a bird, an abstraction. The drawing
illustrates the power of abstraction in modelling and the importance of choosing an
appropriate level and resolution for a model. Despite its simplicity, this picture allows an
unambiguous identification of the species and sex of the bird within a context (e.g. some
location and time).
