Hi, I'm Scientific American podcast editor Steve Mursky.

And here's a short piece from the August 2018 issue of the magazine

in the section called Advances, Dispatches from the frontiers of Science, Technology, and Medicine.

Taking stock of life by Andrea Thompson.

Plants rule the planet, at least in terms of sheer mass.

Many tallies of Earth's life use biodiversity as a measurement

and simply count the number of species.

A new census based on biomass compiled data from hundreds of

studies to determine which kingdoms, classes, and species carry the most global heft. The results show that plants, primarily those on land,

account for 80% of the total biomass, with bacteria across all ecosystems a distant second at 15%.

The findings were published in the proceedings of the National Academy of Sciences.

Higher resolution satellite data and improvements in genomic sequencing have made such measurements possible by yielding more accurate estimates.

But the uncertainty is still high for hard to count life forms such as microbes and insects.

Antarctic Krill, a type of small crustace have a total biomass comparable to that of humans. We make up only 1 one hundredth of a

percent of the total, but we still dwarf that of all wild mammals. Livestock also

dominate. Chickens, for example, account for three times the biomass of wild birds.

The study estimates that humans have decreased the biomass of wild mammals sixfold

and plants twofold through actions such as hunting and

deforestation. That was taking stock of life by Andrea Thompson.