Friday Headlines: 5-3-13

Friday Headlines, May 3, 2013

THE LATEST IN THE GEOSCIENCES

FIRST LAND ANIMALS KEPT FISHLIKE JAWS FOR MILLIONS OF YEARS, SAYS BIOLOGIST

First, I want to clarify, that this refers to land vertebrates, not to land animals. There were most likely already creepy-crawly things on the land, but things with bones colonized the land much later.

The first vertebrates that crawled onto land and had functional, weight bearing limbs are amphibians. Modern amphibians have all sorts of special jaw and tooth adaptations for eating land dwelling plants and other organisms. Fishes have their own jaw adaptations for eating things that live under water.

It appears, based upon the analysis of 89 different fossils of early land-dwelling vertebrates, that the changes to the jaw that allowed amphibians to specialize in eating land-based foods took 40 to 80 million years from the point where the first amphibian walked on land.

FIRST SNAPSHOT OF ORGANISMS EATING EACH OTHER: FEAST CLUE TO SMELL OF ANCIENT EARTH

It’s so esoteric, it’s perfect. Seriously, we can know what the Earth might have smelled like almost two billion years ago!

What this represents is the earliest direct record of heterotrophy, or the process by which an organism gains energy by consuming another organism (in contrast to autotrophy, which refers to organisms making their own food by processes like photosynthesis). We’ve had chemical evidence for heterotrophy in much older rocks, but here the act of one organism consuming another is actually fossilized.

What’s that got to do with smell?

Well, when bacteria consume other organic remains, what we get is that wonderful sulfuric (‘rotten eggs’) smell. So, undoubtedly the environment in which these organisms were once living probably smelled unpleasantly of sulfur!

Thanks to Nick (@Rakados236 on Twitter) for pointing out this headline!