About 237 million years ago:
The sites underscore that this burst of evolution took place much earlier than researchers had thought, particularly for water-loving insects. Among the remains are fossil dragonflies, caddisflies, water boatmen, and aquatic beetles. Until now, paleontologists had thought such aquatic insects didn’t diversify until 130 million years ago. These insects—which include both predators and plant eaters—helped make freshwater communities more complex and more productive, says Zheng, moving them toward the ecosystems we see today.
Elizabeth Pennisi, “Ancient insect graveyards reveal an explosion in bug diversity 237 million years ago” at Science
A friend writes to say that the find is “significantly” earlier than expected – partly on account of fossil evidence, but also partly on account of dates derived from earlier molecular studies. The insect explosion was, no surprise here, concurrent with an “explosion in plant diversity.”
These types of finds scale way back the amount of time needed for the “natural selection is daily and hourly scrutinizing, throughout the world” view of evolution popularized by the adherents of Darwin and still promoted to the public:
“It may be said that natural selection is daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, wherever and whenever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life.” – Charles Darwin
Apparently not. It’s not a slow-mo judgment of “good” and “bad” by a mindless force*.
Abstract: The Triassic represented an important period that witnessed the diversification of marine and terrestrial ecosystems. The radiations of terrestrial plants and vertebrates during this period have been widely investigated; however, the Triassic history of insects, the most diverse group of organisms on Earth, remains enigmatic because of the rarity of Early-Middle Triassic fossils. We report new insect fossils from a Ladinian deposit (Tongchuan entomofauna) dated to approximately 238 to 237 million years ago and a Carnian deposit (Karamay entomofauna) in northwestern China, including the earliest definite caddisfly cases (Trichoptera), water boatmen (Hemiptera), diverse polyphagan beetles (Coleoptera), and scorpionflies (Mecoptera). The Tongchuan entomofauna is near the Ladinian-Carnian boundary in age, providing a calibration date for correlation to contemporaneous biotas. Our findings confirm that the clade Holometabola, comprising most of the modern-day insect species, experienced extraordinary diversification in the Middle-Late Triassic. Moreover, our results suggest that the diversification of aquatic insects (a key event of the “Mesozoic Lacustrine Revolution”) had already begun by the Middle Triassic, providing new insights into the early evolution of freshwater ecosystems. (open access) Middle-Late Triassic insect radiation revealed by diverse fossils and isotopic ages from China Daran Zheng, Su-Chin Chang, He Wang, Yan Fang, Jun Wang, Chongqing Feng, Guwei Xie, Edmund A. Jarzembowski, Haichun Zhang, Bo Wang
Science Advances 05 Sep 2018: Vol. 4, no. 9, eaat1380 | DOI: 10.1126/sciadv.aat1380 More.
- Is this “Big Bang” tendency of life forms some kind of “creationism”? Maybe but, lordy, don’t call it that, okay? Raises the trolls, it does.
But do see also: Not a Big Bang of turtles TOO? Okay, so we were just talking about a Big Bang of birds.
Some speak of a Big Bang of mammals (“These new findings call for a re-evaluation of the evolutionary story of placental mammals,” says Anne Yoder, an evolutionary biologist at Duke University, who wasn’t involved in the work.”) and flowers (“Turns out, these bloomers went through an evolutionary “Big Bang” of sorts some 130 million years ago, a brief era of explosive floral diversification at a time when dinosaurs walked the Earth.”)
and
Stasis: Life goes on but evolution does not happen