Wired Science reports:
The earliest microbes that survived on land may have synthesized fat molecules to prevent their death from dehydration.
The molecules, called wax esters, could have helped the microbes colonize land by protecting them against the harsh environments that probably characterized the lifeless continents, scientists hypothesizes in the March issue of Geology .
"Production of [wax esters] may represent an adaptation to cross a critical evolutionary threshold, i.e. surviving dehydration and/or dessication cycles," wrote David Finkelstein, a biogeochemist at the University of Tennessee-Knoxville, and his co-authors. "This adaptation could have facilitated bacterial migration into the earliest lakes, and aided survival in terrestrial environments."
Little is known about early terrestrial microbial life, which probably colonized land sometime before 500 million years ago. Unlike animals, they don't leave behind much that scientists can find. But these organisms prepared the way for more complex life by seeding the land with organic compounds that became soil.