Creationism in Crisis - How Asia's Mammals Evolved

The evolution of Asia’s mammals was dictated by ancient climate change and rising mountains | Field Museum

Lead author Anderson Feijó holding a plateau pika in Tibet.
Photograph: Danping Mu.

Carrying traps in the Hengduan Mountains.
Photograph:Anderson Feijó.

No doubt to the consternation of any Creationist fraud trying to sell the idea that the Theory of Evolution (TOE) is about to be overthrown and replaced by their favourite Bronze Age fairy tale, researchers from Chicago's Field Museum of Natural History and the Chinese Academy of Science, used their knowledge of evolution to hypothesise that the main evolutionary changes in Asian mammals was directly related to major geoclimatic changes. To test their hypothesis, they mapped the known evolutionary changes in Asian mammals onto the known geoclimatic changes across the continent, and found there was a very good fit.

This will come as no surprise to anyone who understands how environmental change drives evolutionary change because environmental change inevitably involves a change in the environmental selectors operating on the organisms subject to it.

The Field Museum news release explains the research and its significance:

The idea that climate change and geological events can shape evolution isn’t a new one: anyone who’s heard of dinosaurs knows that a big change in the environment (like, say, a meteor hitting the Earth 66 million years ago and causing a chain reaction of storms, earthquakes, cold, and darkness) can dictate how animals live, die, and evolve. But while it’s a generally agreed-upon concept, scientists rely on painstakingly precise data to map how these sorts of changes affect the course of evolution for even one species. A new study in PNAS compiles data on more than 3,000 species to show how climate and geologic changes across Asia over the last 66 million years have shaped the evolution of the continent’s mammals.

Asia has desert up north, tropical forests in the south, temperate forests in the east. My idea was to understand how all these regions were connected and how we ended up with different species of mammals in different areas.

One big step of this project was building a very good understanding of the distribution of mammal species. And this took quite a while because I needed to go through the literature, public databases, and museum collections.

Anderson Feijó, lead author
Key Laboratory of Zoological Systematics and Evolution
Institute of Zoology
Chinese Academy of Sciences, Beijing, People’s Republic of China.

Asia is the world’s largest continent, and it’s home to just about every type of biome.

To understand historical events, scientists look for associations with their timing and location– when and where did species appear, and what else was happening then and there? This paper does that for the entire Asian mammal fauna.

Wat makes [Asia] special is its connections. It’s a crossroads for connections to North America, Africa, Europe, and Australasia.

Bruce Patterson, co-author.
Negaunee Integrative Research Center
Field Museum of Natural History, Chicago, IL, USA

Asia doesn’t have the most mammal species in the world, or the most different kinds of habitats, but The researchers wanted to see how different mammals came to Asia and left from there over time, as well as how new species evolved, and determine whether they could link these changes in Asia’s mammal diversity with changes in the region’s geology (like shifting tectonic plates forming mountains) and climate.

Pikas originated around 15 million years ago on the Tibetan Plateau, and we believe that the formation of this plateau was a big driver of the evolution of this group. Then from there, they colonized the lowlands of northern Asia and then invaded North America, where they're still found today.

[T]his paper made very clear that everything is connected. We are seeing a lot of climate change happen today, and this paper shows that every geological climate change event has led to either diversification or extinction or migration, and we can expect the same thing to happen in the future.

Anderson Feijó

Museums like the Field and the National Zoological Museum of China house collections that include preserved animal specimens and fossils coupled with info about where the animal was found and when. They also used family trees showing how different species are related to shed light on the bigger picture of mammalian evolution. Combining both info, Feijó and his colleagues were able to map where different species have been found over time.

Overall, the researchers found clear links between changes in the Earth’s climate over the past 66 million years and the mammals found in different regions of Asia. As the climate slowly warmed and cooled, some species were driven extinct or moved to new habitats, while others thrived. Similarly, tectonic plate activity, like when the Indian subcontinent inched towards the rest of Asia and eventually crashed into it, buckling the land and forming the Himalayas, played a big role in the movement, extinction, and evolution of mammals.

The researchers were even able to explore the effects of climate and geology on the evolution of individual species; Feijó gives the example of the pikas. Pikas look like their close relatives, rabbits, but have small rounded ears, and they're adapted to live in high altitudes with low oxygen levels.

The team's work is published in PNAS:

Significance

We provide a temporal framework on the relative roles of in situ speciation and historical colonization events in shaping mammal assemblages across Asia. About one-quarter of all colonization events initiated in the tropical forests of Southern Asia, which represents the primary source of mammal lineages. In contrast, our fauna-wide approach reveals that mountain hotspots surrounding the Qinghai–Tibetan plateau acted mainly as accumulation centers rather than as centers of diversification. We further show that the evolution of Asia’s mammal faunas was temporally congruent with other groups and was triggered by common geoclimatic events such as tectonic continental collisions and mountain uplift.

Abstract

Asia’s rich species diversity has been linked to its Cenozoic geodiversity, including active mountain building and dramatic climatic changes. However, prior studies on the diversification and assembly of Asian faunas have been derived mainly from analyses at taxonomic or geographic scales too limited to offer a comprehensive view of this complex region’s biotic evolution. Here, using the class Mammalia, we built historical biogeographic models drawn on phylogenies of 1,543 species occurring across Asia to investigate how and when the mammal diversity in Asian regions and mountain hotspots was assembled. We explore the roles of in situ speciation, colonization, and vicariance and geoclimatic events to explain the buildup of Asia’s regional mammal diversity through time. We found that southern Asia has served as the main cradle of Asia’s mammal diversity. Present-day species richness in other regions is mainly derived from colonization, but by the Miocene, in situ speciation increased in importance. The high biodiversity present in the mountain hotspots (Himalayas and Hengduan) that flank the Qinghai–Tibetan plateau is a product of high colonization instead of in situ speciation, making them important centers of lineage accumulation. Overall, Neogene was marked by great diversification and migrations across Asia and surrounding continents but Paleogene environments already hosted rich mammal assemblages. Our study revealed that synchronous diversification bursts and biotic turnovers are temporally associated with tectonic events (mountain building, continental collisions) and drastic reorganization of climate (aridification of Asian interior, intensification of Asian monsoons, sea retreat) that took place throughout the Cenozoic in Asia.

Feijó, Anderson; Ge, Deyan; Wen, Zhixin; Cheng, Jilong; Xia, Lin; Patterson, Bruce D.; Yang, Qisen
Mammalian diversification bursts and biotic turnovers are synchronous with Cenozoic geoclimatic events in Asia
Proceedings of the National Academy of Sciences (PNAS); 119(49), e2207845119. DOI: 10.1073/pnas.2207845119

Copyright: © 2022 The authors.
Published by PNAS. Open access
Reprinted under a Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).

So, once again, we see not a hint that the TOE is doubted by scientists. In this case, it enabled a hypothesis to be formulated and the hypothesis was validated by the evidence, just as the TOE predicts. I expect Creationist frauds will be informing their cult of the success of the TOE in this piece of research, written on the side of a flying pig.

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