Rivers, Fish and the Tree of Life

Back to Resources
First published on
Tree of Life

Tree of Life
Wikimedia Commons

All life on Earth began in the sea some 3.5 billion years ago. Yet there is a twist to this story. New research shows that almost all fish species that inhabit the oceans today moved there from rivers and lakes. This sheds new light on the importance of freshwater ecosystems for life on Earth. And it suggests that by damming and polluting rivers, we may destroy the seed banks of future generations.

Terrestrial environments occupy 30 percent of the Earth’s surface, but contain 75-85 percent of all species. Freshwater ecosystems only make up about 2 percent of the Earth’s surface, but count as many fish species as the sea, which covers 70 percent of the planet. Why are there so few fish in the sea? Greta Carrete Vega and John J. Wiens, two researchers at Stony Brook University near New York, have found a fascinating answer to this question.

” title=”www.internationalrivers.org/en/blog/peter-bosshard”>www.internationalrivers.org/en/blog/peter-bosshard and tweets @PeterBosshard.