Nature favours creatures in largest and smallest sizes

Surveying the body sizes of Earth's living organisms, researchers from McGill University and University of British Columbia found that the planet's biomass - the material that makes up all living organisms - is concentrated in organisms at either end of the size spectrum. The researchers spent five years compiling and analyzing data about the size and biomass of every type of living organism on the planet-from tiny one-celled organisms like soil archaea and bacteria to large organisms like blue whales and sequoia trees. They found that the pattern favouring large and small organisms held across all types of species and was more pronounced in land-based organisms than in marine environments. Interestingly, maximum body size seemed to reach the same upper limits across multiple species and environments. -Trees, grasses, underground fungi, mangroves, corals, fish, and marine mammals all have similar maximum body sizes. This might suggest that there is a universal upper size limit due to ecological, evolutionary, or biophysical limitations,- says lead author Eden Tekwa, a former postdoctoral fellow at University of British Columbia and now a research associate with McGill University's department of biology. "Life constantly amazes us, including the incredible range of sizes that it comes in,- says co-author Malin Pinsky, an associate professor in the department of ecology, evolution, and natural resources at Rutgers University.