Loss of macroevolutionary species fitness explains the rise and fall of clades

[Dan_Eastwood]

There is some heavy duty mathematical modelling going on here, examining long term diversification and extinction of species. Whether or not we agree with this particular conclusion, it’s impressive work, and I think we will see more studies like this as others adopt and refine the methods.

Loss of macroevolutionary species fitness explains the rise and fall of clades
https://www.nature.com/articles/s41559-025-02873-7

@Quintero et al (2025)

Abstract

How and why species diversity varies over geological timescales remains disputed. Debate revolves around the existence of equilibrium dynamics, the predominance of adaptive radiations and the relative importance of speciation and extinction in driving diversity trajectories. We analyse the evolutionary history of 27 radiations of plants, arthropods and vertebrates, with phylogenetic information incorporating extinct and extant species under a new ‘fossilized birth–death diffusion’ model that provides a detailed characterization of past diversification and resulting diversity dynamics. Here, lineages undergo speciation and extinction rates that diffuse continuously in time and generate fossils with rates that can vary with stratigraphy. Clade diversity trajectories follow rise and decline dynamics, with fast accumulation following recurrent speciation while slowdowns and losses are modulated primarily by changes in extinction. Diversity dynamics do not appear to be governed by clade-level processes expected from adaptive radiations or diversity dependence. Rather, these patterns emerge from dynamics at the species level, where lineages tend to become increasingly vulnerable to extinction and less likely to speciate with time. Those species that counteract this trend create and maintain biodiversity through deep time. The rise and fall of clades results from species-level fates.

[Rumraket (Mikkel R.)]

Paywalled.

@Quintero et al (2025)

lineages tend to become increasingly vulnerable to extinction and less likely to speciate with time.

Do they say anything about what is causing this tendency for some lineages in their model? Do they mean to say that declining speciation rates is the cause of increased probability of extinction?

[Dan_Eastwood]

@Rumraket

@Quintero et al (2025)

lineages tend to become increasingly vulnerable to extinction and less likely to speciate with time.

Do they say anything about what is causing this tendency for some lineages in their model? Do they mean to say that declining speciation rates is the cause of increased probability of extinction?

As I understand it, it’s that species within the clade tend to become more specialized for a particular environment over time, with a occasional exceptions that are able to diversify and survive. It’s the species going extinct that drive the trend, rather than a trend for a lineage going extinct.

[sfmatheson (Stephen Matheson)]

@Rumraket

Paywalled

I think this is the preprint version but I haven’t looked really hard to verify. For the Nature version I will get the PDF very soon (tonight) and can share it on request.