Collective behavior is wide-spread in animal communities, from bacteria
to humans.  In some cases natural selection can work at levels above 
the individual, as in the social insects.  In other cases, macroscopic
dynamics phenomena represent the emergent collective consequences 
of individual decisions, and of the selfish evolution of genomes.   
This lecture will begin with a review of models of collective dynamics 
of animal aggregations, and then explore how these relate to the evolution
of searching and foraging behavior.