Author: BBC World Service

This week, the world’s largest cruise ship set sail from Miami. Whilst a cruise holiday may be appealing to some, there is also a long history of disease spreading around the world via ships. Marnie and the panel take a look at the reasons why and the resulting impact on public health policies. It’s not just humans and microbes that are hitching a ride aboard sea vessels. Animals such as mussels can cling on to ship hulls, exposing previously pristine environments to potentially invasive species. We hear how scientists are tackling this problem with novel polymer lubricants. And we’re not done yet with marine creatures creating big issues. Professor John Parnell tells us the huge impact microscopic phytoplankton has had on Earth’s geology, and how the stuff in your pencils could actually be the bodies of long dead plankton... Plus, we explore the latest developments in rhino IVF, say ‘saluton’ to our Esperanto listeners and answer a question about going grey. And as Alabama uses nitrogen to execute a prisoner, we look at the science behind death penalty drugs. Presenter: Marnie Chesterton, with Yangyang Cheng and Philistiah Mwatee Producer: Sophie Ormiston, with Margaret Sessa Hawkins, Alex Mansfield, Dan Welsh, Harrison Lewis, Katie Tomsett and Jack Lee Production Co-ordinator: Jonathan Harris

Presenter Marnie Chesterton and the team pit their wits against a multitude of mind-bending puzzles from an old TV gameshow - all in the name of answering a question from Antonia in Cyprus: how do we work out how clever someone is? Is IQ the best measure of cleverness? Why do we put such weight on academic performance? And where does emotional intelligence fit into it all?

In the search for answers Marnie and the team are locked in rooms to battle mental, physical, mystery and skill-based challenges, all against the clock.

Unpicking their efforts in the studio are a global team of cleverness researchers: Dr Stuart Ritchie from Kings College London, Prof Sophie von Stumm from York University and Dr Alex Burgoyne from Georgia Institute of Technology in the US.

They are challenged to face the toughest questions in their field: Why do men and women tend to perform differently in these tests? Is our smartness in our genes? And what about the Flynn Effect – where IQs appear to have risen, decade after decade, around the world.

Producer/presenter: Marnie Chesterton Editor: Richard Collings Production co-ordinator: Jonathan Harris

(Photo Man doing puzzle. Credit: Getty Images)

Molecular biologist Prof Jason Chin tells us about his research into accelerated evolution and how it could help create new substances to be used in medicine, chemistry and more.

In South America, palaeogeneticist Dr Verena Schuenemann has been extracting genetic material from human remains to find out more about treponemal diseases, which include syphilis, yaws and bejel.

And moving across the Atlantic to the Mediterranean, volcanologist Professor Timothy Druitt has discovered new evidence of a massive volcano that erupted beneath the sea near Santorini around 500,000 years ago.

Staying in the Mediterranean, we speak to Professor Rachel Flecker, co-chief scientist on Expedition 401 of the International Ocean Discovery Program. She and her team are drilling down into the seabed to establish how the Gibraltar Strait has altered over time. As well as influencing the Mediterranean's salinity, this changing movement of water has impacted the entire planet's oceans and climate.

Presenter: Roland Pease Producer: Alice Lipscombe-Southwell Production co-ordinator: Jana Bennett-Holesworth

(Image Credit: Thomas Ronge)