# Stanford Study Confirms Why Earth's Greatest Mass Extinction Wiped Out Some Species but Spared Others

*2026-07-12 22:01 UTC · Science · 1 min read*

> A Stanford-led study confirms Earth's largest mass extinction 252 million years ago selected victims based on their metabolic tolerance for heat and low oxygen.

Stanford researchers led by Jose Andres Marquez, working under senior author Erik Anders Sperling, have confirmed why the Permian-Triassic extinction 252 million years ago killed off ancient seafloor life like brachiopods and sea lilies while sparing faster-metabolizing mollusks, fish and echinoderms. The study, published July 6 in Proceedings of the National Academy of Sciences, is the first to factor in the biological metabolism of the affected animal groups.

The "Great Dying" wiped out 96% of marine species and 70% of land animals after a surge of volcanic activity pushed ocean temperatures up 8-12°C over thousands of years and drained oxygen from the water. Slow-metabolizing filter feeders like brachiopods could not cope with the heat and low oxygen; only about 400 brachiopod species remain today, compared with 10,000-15,000 modern bivalve species descended from the extinction's survivors.

Sperling said the biggest mass extinction of all time started from a world very similar to today's. Current warming projections of 1.5-4°C by 2100 are far below the Great Dying's 8-12°C increase, but the study suggests even smaller shifts could strain marine life with similar metabolic vulnerabilities.

## Sources

- [eurekalert.org](https://www.eurekalert.org/news-releases/1135567)
- [sciencedaily.com](https://www.sciencedaily.com/releases/2026/07/260711010122.htm)

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TechTools News · https://techtools.cz/tools/news/article/1995-stanford-study-confirms-why-earth-s-greatest-mass-extinction-wiped-out-some
Česká verze: https://techtools.cz/tools/news/clanek/2068-studie-stanfordovy-univerzity-potvrdila-proc-nejvetsi-vymirani-v-dejinach-zeme