Life on Earth Not Getting Much Bigger

According to scientists, the scale of life on Earth won't likely expand beyond its present limits.

Analysis of the fossil record shows that life has undergone two profound jumps in size — from bacteria to eukaryotic cells, and from single-celled to multi-celled organisms.

In each case, possible body size increased by a factor of one to two million. After the second jump, say comparative zoologists, bodies hit the limits of Earthly possibility. Both of these jumps coincided with massive increases in atmospheric oxygen, and another such increase in geochemical nutrients is unlikely.

Today's blue whale is about ten times larger than any other animal. If there were a species whose individuals were a million times the mass of a blue whale, their nutrient demands would be so large that you couldn't have many species like that on the planet. Potentially you could have just one, according to the researchers.



Original article here.