Cambrian explosion of life, about 540 million years ago, was seen for more than two centuries as the key moment of the emergence of terrestrial life ,event associated in the past with the moment of Divine Creation. 13 years passed until, in 2004, the International Union of Geological Sciences (IUGSA) said there is a new geological era, the Ediacaran, the Era of life before… life.
575 million years ago, long before the Cambrian explosion, life oceans were soaking of life. A strange group of organisms, named rangeomorphs, probably some of the first animals that ever appeared on Earth, was adapted to the conditions of those times and prospered in the aquatic environment, the only one allowing the existence of life. The way they lived and then disappeared, has been another mystery.
A new computer model, developed by the researchers at Cambridge University, provides answers on this begining issue in the evolution.
Rangeomorphs were some of the first large organisms on Earth, occurring when most of life was represented by microscopic creatures.
Most rangeomorphs weren’t longer than 10 inches, but archaeological evidence has shown that some of these organisms could even reach up to two meters long. The earliest appear in the geological records 635 million years ago, disappearing for good 541 million years ago.
They were strange looking creatures, resembling the leaves of plants rather than animals of today modern patterns. In fact, rangeomorphs doesn’tresemble any known animal, which is why it was very difficult to know how they, for example, feeding or multiply.
” We know that rangeomorphs were living at considerable depths, depths too great to allow the photosynthesis process of plants needed. Most likely, these primitive organisms were absorbing nutrients directly from seawater through the outer shell. Today, it would be extremely difficult for an organism so big to survive only on nutrients dissolved in the water of the seas and oceans “, said Dr. Jennifer Hoyal Cuthill, team leader of the rangeomorphs paleontologists involved in the study.
Existing data today shows that Ediacaran oceans were like a soup repleted with nutrients like organic carbon, which allowed the development of organisms like rangeomorphs. 541 million years ago along with the Cambrian explosion of life, the circumstances have changed suddenly, facilitating the emergence of most animal groups existing today, as well as some that have disappeared. Competition for resources has increased dramatically and rangeomorphs became sure victims.
Even if today is considered a progressive failure, given the sudden disappearance 541 million years ago, rangeomorphs, however, represented a major success of ediacarian life.
” Such creatures are extremely well adapted to their environment. Mathematically speaking, they have filled their niches almost perfectly. But time has come for them fateful in early Cambrian and the oceans have seen the top predators in the history of life. Complete defenseless, rangeomorphs were unable to change and Terra have never seen bodies like them ” concludes Dr. Hoyal Cuthill.
