What's Earth's dominant species by mass?
Earth’s “dominant species” by mass turns out to be surprisingly hard to pin down, with candidates ranging from farmed chickens and crop grasses to deep-sea fish, underground microbes, and even viruses, depending on how biomass is counted. Commenters point out that many overlooked groups — like anaerobic bacteria in rock, bristlemouth fish in the oceans, and vast stands of trees and grasses — likely outweigh familiar megafauna such as whales or humans. The exchange also highlights how a single species with relatively modest biomass, humans, has radically reshaped global ecosystems through agriculture, industrial fishing, and habitat conversion.
Overall focus of the thread
- Readers debate what truly counts as Earth’s “dominant species by mass,” challenging omissions and assumptions in the article.
- Multiple comments extend the discussion beyond trees, humans, and classic examples into microbes, marine life, and domesticated animals.
What should count in biomass comparisons
- Some argue anaerobic underground bacteria might dominate because they occupy 3D rock volume; others respond that dominance is by mass, not volume, and that lumping all such bacteria into “one species” is invalid.
- Several note that bacteria, archaea, and viruses were not calculated or are underemphasized, despite being “everywhere.”
- Questions raised about why algae and generic plankton are missing.
- Debate over grasses: article mentions crops like rice, wheat, maize, and sugar cane, but commenters point out wild grasses and grasslike families (Poaceae, sedges, rushes) are largely ignored.
- Bamboo is proposed as a contender, but others argue its mass is split across many species.
Animals, oceans, and trophic constraints
- Some are surprised whales are absent; others note individual whales are huge but numerically scarce, and their populations have not recovered.
- Deep-sea bristlemouths and especially Cyclothone alba are suggested as potential biomass leaders; rough back-of-the-envelope estimates claim they could vastly exceed tree biomass.
- Counterpoint: whatever those fish eat must collectively outweigh them, though that food is more taxonomically diffuse.
- Krill and marine bacteria are implicitly suggested as overlooked.
Definition and counting issues
- Dispute over whether humans are “just one species”: reply clarifies the claim concerns currently existing Homo species.
- Discussion of whether dead wood in trees should count as biomass; some argue it’s structural and functional (like bone), so it should count, others see it as “cheating.”
Domestication, biodiversity, and ethics
- Noted that ~two-thirds of avian biomass is poultry; linked to concerns about factory farming conditions and rapid turnover by slaughter.
- Comparison of wild panda numbers to the number of fast-food outlets; used to highlight how consumer brand proliferation can exceed wildlife populations.
- Onion-style satire referenced about consumer product diversity exceeding biodiversity.
Scale, density, and human impact
- Several dimensional-analysis riffs: all humans fitting into a small cube or within Texas at urban-like density; contrasted with resource and infrastructure realities.
- Side discussion on aliens viewing humans as unusually transformative: replacing megafauna with livestock, altering ecosystems, and possibly being quarantined or used as “entertainment.”
- Others argue such planetary-scale disruption is just another example of life-driven atmospheric and ecological change, comparing humans to cyanobacteria’s ancient oxygenation event.