This helps reduce complexity and bugs (for you and the module authors) by organizing code into well-tested, reusable components.
However, module A might depend on B, which depends on C, D, and E.
Installing from their package managers is the preferred and easiest method to install bioperl, even if their version is a bit out of date.
If your distribution does not package bioperl, or if for some reason you prefer to install it from source, then continue reading.
The first time you run cpan it will ask a bunch of questions, the defaults will work 99% of the time, so accept them all.
A distribution may contain just one module, or a set of modules.
A distribution may require modules from other distributions, either as part of its implementation or to extend another module's functionality. Rather than rewriting code, module authors can simply reuse existing code from other modules.
CPAN or also known as Comprehensive Perl Archive Network is a repository for modules written in Perl.
Currently, there are 177,000 published modules which can be downloaded and used by the Perl software developers or by the system/network administrators.