As I suspected, the Responsive theme hard codes a biography box into
single.php, the single post template.
This is quite a common occurrence, so much so that it's an entry in WP Biographia's FAQ, which is always worth reading when something odd happens ... see http://wordpress.org/extend/plugins/wp-biographia/faq/ and/or http://www.vicchi.org/codeage/wp-biographia/3-frequently-asked-questions/#faq6, which says ...
I've installed and configured WP Biographia and now I see not one but two differing Biography Boxes; what's going on?
There's probably one of two things going on here. Firstly, you've already got another plugin that makes a Biography Box installed and active and this plugin, as well as WP Biographia, are doing their job properly. Secondly, the theme you're using hard codes a Biography Box into the theme templates. Both the TwentyTen and TwentyEleven themes supplied as part of a standard WordPress install do this.
To get around this, you'll either need to comment out or delete lines 51 through 59 in
/wp-content/themes/responsive/single.php (based on version 220.127.116.11 of the theme). It would be nice if theme designers made this configurable, but sadly a lot don't.