Computer simulation of the evolution of foraging strategies:

Computer simulation of the evolution of foraging strategies: Application to the ichnological record

Plain-Language Summary:

Trace fossils are fossilized remains of traces and trackways. Such fossils are very common, and they make it possible to follow the evolution of feeding strategies of invertebrate animals that eat food particles on the sea floor. [For illustrations of a large number of real trace fossils, see http://www.emory.edu/GEOSCIENCE/HTML/images.htm. These animals try to cover a large area efficiently, but it is evident from the fossil record that efficient foraging patterns took a long time to evolve.

In this paper, an attempt is made to simulate the evolution of neural networks that can give efficient foraging. An evolutionary system is set up in the computer, where simulated organisms contain artificial neural networks that can mutate and evolve. The organisms can also "mate", exchanging genetic material. In the experiments, efficient foraging strategies evolve, comparable to the patterns seen in nature. Meandering is one such strategy that emerges in the computer. The distribution of evolutionary rates over time can also be compared to natural patterns, including "punctuated equilibria".

Though these experiments are simplistic and primitive, they demonstrate how evolution can work and how small neural networks can give surprisingly complicated behaviour. This is a point to keep in mind when considering the evolution of foraging strategies.

Glossary (in order of appearance, in abstract and article):

Ichnology: The science of traces and tracks made by organisms
Neural network: A system of computer hardware or software modeled after the cells in a biological nervous system and intended to simulate the way in which a brain processes information, learns, and remembers (Computer Dictionary, Microsoft Press, 1991).
Ethology: The science of animal behaviour
Metazoan: Animal
Vendian: A geological period prior to the Cambrian
Phanerozoic: The time span from the Cambrian until now
Adaptive radiation: Fast evolutionary emergence of new forms
Punctuated equilibra: Long periods of evolutionary standstill, broken by rapid speciation
Stasis: Long period of evolutionary standstill
Neuron: Brain cell
Allopatric speciation: Formation of new species in isolated subpopulations

Oyvind Hammer, Paleontological Museum, Sars gt.1, N-0562 Oslo, Norway