Seminar 19th April 2011 noon University of Southampton, Building 46 (ORC) Room 2005
The evolution of complex organisms: an adventure quest?
University of Southampton, ECS
- Web page
- Complex Systems
- Petrina Butler
How evolution creates complexity and novelty is poorly understood. Recent evidence from fields as wide as evolutionary simulation, protein engineering and field studies shed new light on the process, and viewed together are beginning to question the traditional view of evolution as a slow, steady process. Meanwhile, the reason for the apparently ubiquitous presence of hierarchy and modularity in complex organisms is an open question. Recent evolutionary simulation studies have for the first time demonstrated evolution of spontaneous modularity, suggesting that it occurs as a response to variable environmental conditions – however, the issue remains unclear.
The Adventure Quest model brings together evidence and ideas from these fields to describe a framework for the evolution of complexity that emphasises the importance of variable environmental conditions in breaking down complex adaptations into manageable (i.e. findable) chunks. It views complexity as being built up by 'collecting' useful modular adaptations from different environments where they are available, and combining them to access new and more complex niches. Furthermore, it predicts that evolution occurs in two different ways: Changing, or 'tweaking' existing adaptation functionality is likely to be easily achieved by gradual sequential improvements, following simple fitness gradients – similar to how evolution has been traditionally perceived; On the other hand, finding novel adaptations is likely to be controlled by effectively random search, because no usable fitness gradients are likely to exist. From this perspective, the ubiquity of hierarchy and modularity in complex organisms is then explained as a short-cut 'heuristic' that enables more effective random search for novel adaptations by recursively reducing the size of the search space.
This talk will focus specifically on why the discontinuous nature of the real world leads to things we would call 'modules', how natural selection deals with them, and how in doing so it may create some of the macro patterns we observe in living organisms, ecosystems and the fossil record.
Dr Alex R Kraaijeveld
Lecturer in Ecology & Evolution
School of Biological Sciences
University of Southampton
Tel: +44(0)23 80593436