Programme 5 in the BBC Radio 4 series "Planet Earth Under Threat" was called The Conundrum of Biodiversity and was presented by Gabrielle Walker.

It used Madagascar as a prime example of a biologically diverse environment, and how that is being constantly threatened by so called "Slash and Burn" (wikipedia) agriculture.

It also featured former "Tomorrow's World" presenter Howard Stableford in conversation with Dr. Edward Wilson. Wilson won the "Dian Fossey Gorilla Fund International's Global Conservation Award" in 2006.

The show has its own blog at Planet Earth Under Threat, and each episode will be available online following the broadcast.

Listen to episode 5 at The Conundrum of Biodiversity. RealPlayer or RealAlternative required.

Incidentally, "Tomorrow's World" was back in the public eye this week. While the BBC are not resurrecting the actual show, they are bringing back the "brand" - Tomorrow's World to return to BBC.

The BBC is bringing back the Tomorrow's World brand to help audiences understand new technologies.

Presenter Maggie Philbin will be offering in-depth analysis on technology stories on TV, radio and the web under the Tomorrow's World banner.

Although the programme - which ran from 1965 to 2003 - will not return, elements such as the logo and title sequence will be revived.

Philbin says using the brand "fits perfectly with technological change".

Here's a couple of musical gems from the "Tomorrow's World" archive's...