Edie Stewart M, Collins Katie S, Jablonski David
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA.
Natural History Museum, London, London SW7 5BD, UK.
Sci Adv. 2025 May 23;11(21):eadv1171. doi: 10.1126/sciadv.adv1171. Epub 2025 May 21.
The end-Cretaceous (K-Pg) mass extinction shows how large-scale taxonomic loss affects functional diversity over short and long timeframes. In a macroevolutionary model system, we find that, despite losing ~60% of genera and ~20% of family-level diversity, marine bivalves lost only ~5% of their functional diversity, inconsistent with random extinction. Even with evolutionary opportunities presented by a disrupted ecosystem, low-diversity groups prior to the extinction or those originating in the Cenozoic rarely reach higher ranks today, implying long-term diversity ceilings to certain ecological roles. Clades that survived the extinction tend to dominate functions today, 66 million years post-extinction, but both relative richness and phylogenetic structure of those functional groups have been significantly shuffled. Thus, neither the composition of the pre-extinction biota nor the set of taxa that survived the extinction fully accounts for the functional and phylogenetic structure of today's biota. The extinction disrupted Mesozoic biodiversity but did not fully determine the present-day configuration.
白垩纪末期（K-Pg）的大规模灭绝显示了大规模的分类学损失如何在短期和长期时间框架内影响功能多样性。在一个宏观进化模型系统中，我们发现，尽管海洋双壳类动物失去了约60%的属和20%的科级多样性，但它们仅失去了约5%的功能多样性，这与随机灭绝不一致。即使有被破坏的生态系统所带来的进化机会，灭绝前的低多样性类群或那些起源于新生代的类群如今很少能达到更高的分类等级，这意味着某些生态角色存在长期的多样性上限。在灭绝事件中幸存下来的类群如今往往主导着各项功能，在灭绝事件发生6600万年后，但这些功能类群的相对丰富度和系统发育结构都已被显著打乱。因此，灭绝前生物群的组成以及在灭绝事件中幸存下来的分类单元集合都不能完全解释当今生物群的功能和系统发育结构。这次灭绝打乱了中生代的生物多样性，但并没有完全决定当今的生物多样性格局。
