Darwin’s Dilemma solved: what happened during the “Cambrian explosion”?




A new study by scientists from Adelaide for the first time allowed us to estimate the rate of evolution during the “Cambrian explosion” which occurred in the period between 540 and 520 million years ago, when there was the majority of modern animal groups. The findings, published in the journal Current Biology, allowing “Darwin’s dilemma”: the sudden appearance of many modern groups of animals in the fossil record in the early Cambrian period.

“The dramatic emergence of dozens of groups of animals in this period was perhaps the most important evolutionary event since then, as life began,” – says a leading lecturer Michael Lee of the School of Earth and Environmental Sciences at the University of Adelaide. – “These amazingly rapid evolution that are implied by these Cambrian explosion, long exploited by opponents of evolution. Darwin himself believed that it is contrary to the normal evolutionary process. ”

Because of the imperfections of ancient fossils no one has been able to accurately measure the rate of evolution in this critical interval, often called the Big Bang to the evolution.

“In the study, we assess the rate of morphological and genetic evolution during the” Cambrian Explosion “: it was five times higher than today – quite fast, but it is consistent with Darwin’s theory of evolution.”


The team, which includes scientists from the Natural History Museum in London, has estimated the anatomical and genetic differences between live animals and established a time frame in which these differences are accumulated, based on data collected in the fossil record, and sophisticated mathematical model. The simulation showed that a relatively small acceleration of evolution was enough to explain the sudden appearance of many groups of animals developed during the Cambrian explosion.

Living fossil arthropods – centipede Cormocephalus – had to crawl 515 million years of the Cambrian period, in order to grow out of the trilobite Estaingia. The study arthropods showed that their anatomy and genes have evolved to five times faster during the Big Bang, evolution, compared with all subsequent periods. It’s fast enough, but it is compatible with the theory of Darwinian evolution. As a centipede and trilobite found today on Kangaroo Island in Australia.

The study was focused on arthropods (insects, crustaceans, arachnids, and their relatives) who were and are the most diverse group of animals in the Cambrian period, and in our days.

“It is in the Cambrian period, as many believe, arthropods have a hard exoskeleton, connected legs and compound eyes, which is featured in all arthropods. In the fossil record have brought even the appearance of antennas, which have centipedes and lobsters, as well as the very first biting jaws “- said Dr. Greg Edgecombe.

Curiously, what if life is older than the Earth itself ? Whether she had similar “Cambrian explosion” outside world? Pockets of life being found to this day .
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Tags: Biology , Life , Evolution .


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