Punctuated ecological equilibrium in mammal communities over evolutionary time scales

Abstract

The study of deep-time ecological dynamics has the ability to inform conservation decisions by anticipating the behavior of ecosystems millions of years into the future. Using network analysis and an exceptional fossil dataset spanning the past 21 million years, we show that mammalian ecological assemblages undergo long periods of functional stasis, notwithstanding high taxonomic volatility due to dispersal, speciation, and extinction. Higher functional richness and diversity promoted the persistence of functional faunas despite species extinction risk being indistinguishable among these different faunas. These findings, and the large mismatch between functional and taxonomic successions, indicate that although safeguarding functional diversity may or may not minimize species losses, it would certainly enhance the persistence of ecosystem functioning in the face of future disturbances.

PISA data clusters reveal student and school inequality that affects results

“…This type of data where different groups (here countries) are distributed differently in a possibly multidimensional space can be difficult to interpret based on simple correlations, and the large-scale patterns in the data can be difficult to find. A growing body of research is therefore developing, mainly in the field of theoretical ecology [ 24 – 28 ], to employ methods from network theory to find these patterns by, for example, representing species distributions in geographic space [ 24 – 26 ] or in a space of climatic variables [ 27 ] as networks in order to study their structure. We here apply this framework to the PISA data to identify clusters of countries that are connected together due to their students performing similarly in PISA while at the same time having a similar socio-economic background, meaning that their students are distributed similarly in the ESCS-Points space.…”

“…In this work we therefore apply tools from this field, previously applied mostly in theoretical ecology on species distribution data [ 24 – 28 ], to find patterns in the PISA data that can tell us something about the structure in performance and socio-economic background of the students and further nuance the PISA results.…”

The simple emergence of complex molecular function

“…In a viroid-free situation, it is highly likely that similar viroid-like replicators would emerge in short evolutionary time, occupying the vacant niche in the same way that radiating species do [103]. Macroecological niches enjoy long periods of functional stasis, even in the face of taxonomic variability [104]. At odds with macroevolution and macroecology [105], an integration of molecular ecology and evolution (and phylogeny) is yet to be worked out.…”

The simple emergence of complex molecular function

“…In a viroid-free situation, it is highly likely that similar viroid-like replicators would emerge in short evolutionary time, occupying the vacant niche in the same way that radiating species do [102]. Macroecological niches enjoy long periods of functional stasis, even in the face of taxonomic variability [103]. At odds with macroevolution and macroecology [104], an integration of molecular ecology and evolution (and phylogeny) is yet to be worked out.…”