How life's forms modify and evolve the Earth: ants & flowers (Introduction)

by David Turell @, Tuesday, March 12, 2024, 16:44 (40 days ago) @ David Turell

How stem ants became modern ants:

"By analyzing the extensive fossil record alongside a very detailed tree of life for ants, evolutionary biologists have shown how the rise of flowering plants helped ant species thrive. The work, reported this week in the Proceedings of the National Academy of Sciences, validates a nearly two-decade-old idea that angiosperms had been central to the insects’ success but adds a new twist: Without the opportunities provided by these newly evolving plants, ants might have disappeared.

"Today, there are an estimated 2.5 million “modern” ants for each person on the planet, distributed around the world and playing key roles in many ecosystems. Yet for their first 30 to 50 million years, ants were small potatoes, so to speak. And, as flowering plants replaced ferns and conifers, these early “stem” ants began to disappear. (my bold)

"Many scientists assumed modern ants simply outcompeted these earlier evolving species, but this new research suggests otherwise. The authors say it’s more likely these early ants had become so specialized, with adaptations to their mouths and body parts to catch certain foods, that they could not adapt to the changing environment the way their more recently evolved relatives did. In that way, the stem ants may well have been extinction-prone, says Joseph Parker, an evolutionary biologist not involved in the research. “Maybe we wouldn’t have ants today were it not for early angiosperms.'”

From the original article:

"Our results challenge one of the most common hypotheses explaining ant extinction: the competitive exclusion of stem ants by crown ants. Instead, the Angiosperm Terrestrial Revolution acted as a buffer against extinction and a driver of diversification in ants. Our approach clarifies one of the most widely accepted patterns in insect–plant diversification.


"we conducted a comprehensive analysis using a large dataset that includes both the ant fossil record (~24,000 individual occurrences) and neontological data (~14,000 occurrences), and tested four hypotheses proposed for ant diversification: co-diversification, competitive extinction, hyper-specialization, and buffered extinction. Taking into account biases in the fossil record, we found three distinct diversification periods (the latest Cretaceous, Eocene, and Oligo-Miocene) and one extinction period (Late Cretaceous). The competitive extinction hypothesis between stem and crown ants is not supported. Instead, we found support for the co-diversification, buffered extinction, and hyper-specialization hypotheses. The environmental changes of the ATR, mediated by the angiosperm radiation, likely played a critical role in buffering ants against extinction and favoring their diversification by providing new ecological niches, such as forest litter and arboreal nesting sites, and additional resources. We also hypothesize that the decline and extinction of stem ants during the Late Cretaceous was due to their hyper-specialized morphology, which limited their ability to expand their dietary niche in changing environments. This study highlights the importance of a holistic approach when studying the interplay between past environments and the evolutionary trajectories of organisms."

Comment: the dynamic interplay of different organisms is clearly shown in this study.

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