Marine life during the Cambrian explosion 520 million years ago. (Katrina Kenny & Nobumichi Tamura)
Evolution during the “Big Bang of Evolution,” also known as the Cambrian Explosion, happened at five times the rate it occurs today, according to a new study, a finding that is consistent with Darwin’s theory of evolution.
The Australian researchers said they’ve been able to estimate, for the first time, just how fast life evolved during an incredibly productive period in Earth’s history some 520 to 540 million years ago. It was during this Cambrian explosion when most modern animal groups first appeared on Earth.
The research group’s findings, published in Current Biology, also provide an answer to Darwin’s dilemma.
In his classic book “On the Origins of the Species,” where he lays out his theory of evolution, 19th century scientist Charles Darwin pointed out a potential problem with his theory.
While there was a rich fossil record of creatures dating from the beginning of the Cambrian Period, Darwin thought a lack of fossils from the years prior to that geologic time period might present a contradiction to his evolution theory.
“The abrupt appearance of dozens of animal groups during this time is arguably the most important evolutionary event after the origin of life,” says lead author and associate professor Michael Lee of the University of Adelaide in South Australia.
Critics of Darwin’s theory of evolution have pointed to the nearly impossibly fast rates of evolution to discredit Darwin’s work.
Up until this new research, no one has been able to accurately measure the rates of evolution during this prolific period because of the “notorious imperfection” of the ancient fossil record.
A living arthropod, centipede Cormocephalus crawls over a fossil of its 515-million-year-old relative, trilobite Estaingia, which lived during the Cambrian explosion. (University of Adelaide)
In this new study, the researchers said that they were able to estimate that rates of both structural and genetic evolution of creatures that took place during the Cambrian explosion were five times faster than they are today. The scientists say these changes are also consistent with Darwin’s theory of evolution.
The researchers focused their work on invertebrate animals called arthropods because they considered them to be the most diverse animal group that existed both back during the Cambrian period as well as today. This group of animals includes insects, crustaceans and arachnids.
“It was during this Cambrian period that many of the most familiar traits associated with this group of animals evolved, like a hard exoskeleton, jointed legs and compound (multi-faceted) eyes that are shared by all arthropods. We even find the first appearance in the fossil record of the antenna that insects, millipedes and lobsters all have, and the earliest biting jaws,” said co-author Dr. Greg Edgecombe of London’s Natural History Museum.
Thank you for this blog post. I did not know that Darwin was concerned about the worthiness of his theory. I am unqualified and worse, unable, to understand even the abstract of the research that claims to provide consistency between the Cambrian Explosion and Darwin’s theory. I do think though it is important that there was a reference to this research, but in this post and others in the science blog there are too many extraneous links.