Terrestrial life as we know it couldn’t exist without soil. Soil, as we know it today, is a layer of minerals, organic matter, liquids, gasses and organisms that not only provides a medium for plant growth, but also modifies the atmosphere, provides a habitat for animals and retains and purifies water.

This kind of soil hasn’t always existed, so in order to understand early conditions on land, we first need to understand what can be constituted as a soil and when these first appeared. Is there soil on the Moon? Can soil fossilise?

Since most terrestrial ecosystems are rooted in soil, if we want to understand how life established itself on land, we first need to know how soils form, how they have changed over geological time and which kinds of plants and fungi can live without it.

Joining us in this episode is Dr Ria Mitchell, Experimental Officer in X-ray Computed Tomography at the University of Sheffield, UK.

Direct download: Ep123.mp3
Category:general -- posted at: 5:12pm UTC

Part two of our interview with Dr Larisa DeSantis of Vanderbilt University on the 'dietary ecology' of Smilodon.

Smilodon is probably one of the most iconic mammalian apex predators with its extended upper canines and robustly-built forearms. In fact, when we compare Smilodon to modern cats (felids), we don't see these same characteristics. So what were they used for? Was Smilodon specialised for any particular behaviour?

Owing to the unique preservation of the tar seeps at Rancho La Brea, Los Angeles, USA, we can find an overabundance of predators, including Smilodon fatalis, Canis dirus, Panthera atrox and Puma concolor. This allows researchers to reconstruct the predatory landscape of the area in the Pleistocene. Who was eating what? Was there any competition between predators?

Direct download: Ep122.mp3
Category:general -- posted at: 2:48pm UTC