Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Metre-Long Medusas And Molluscs Seize The Ocean

27.11.2002


The first outbreak of the evolution of multicellular organisms falls on the Wend, the last period of the Proterozoic (Precambrian), about 620-550 million years ago. At that time, climate of our planet was rather cold, and glaciers that covered the single supercontinent nearly reached the equator. The cold is beneficial for the evolution of sea creatures.



In modern seas, significant concentrations of dissolved oxygen, phosphates, and the organic matter provide for a high biological productivity and the appearance of very large animals. In ancient times, the situation was probably similar: first multicellular organisms lived in cold seawater.

As is known, there was a sharp increase in the fauna diversity in the Cambrian Period. However, in the preceding period, Wend, the fauna was rather rich too, as said Mikhail A. Fedonkin in his report of October 17 in the Vavilov Institute of General Genetics (Moscow). Fedonkin is the corresponding member of the Russian Academy of Sciences and the head of the Laboratory of Precambrian Organisms in the Paleontological Institute in Moscow.


Most exiting news has come from the White Sea area. Imprints of various creatures are found within deposits of the Wend Period (clay and sandstone strata with a total thickness of about one kilometre). Some of those creatures resemble modern sponges. Others are like polyps: actiniae or sea anemones plunged into the ground so that only the crown of tentacles is left above. Some animals were real giants: medusas that were attached to the sea bottom reached one meter in diameter!

However, German palaeontologist Adolf Seilacher recently stated that the fauna of the Wend had no relationship with any of modern types and classes of animals, but was a unique evolutionary experiment: there was the world of giant unicellular organisms. But studies of Russian scientists refuted this extraordinary hypothesis.

Specialists from the Paleontological Institute of the Russian Academy of Sciences proved using numerous facts that many Precambrian creatures had a three-dimensional shape (but not a two-dimensional plate-like shape, as Seilacher suggested). In addition, some of them were capable of moving: their pathways were found in fossils together with their body imprints. For example, one weird creature (Dikinsonia), which was one-meter-long, round-shaped, and covered with rough skinny shell, moved about with casual changes in direction and stops, like modern invertebrates do when look for food. A giant cell cannot be so bulky and crawl that way. So, the Seilacher’’’’s hypothesis is obviously false: the fauna of the Wend was multicellular.

Another curious animal (Kimberella) was reconstructed by Australian palaeontologists from imprints as a medusa and shown in that form in some books. However, that reconstruction was based on too many assumptions. Recently, Russian scientists have revealed that it was not a medusa, but a mollusc: a kind of a large snail that appeared from its shell as a fluffy frill resembling old-fashioned Spanish neckwear.

Such creatures populated warm water basins in the Cambrian Period, about 500 million years ago. An increased concentration of carbonates in warm water allowed the fauna to build a more complex skeleton. At that time, first attempts to conquer the land were done. Fedonkin and his colleague E. Echelson from the United States have made a detailed description of fossil imprints resembling those of automobile tires and left by large animals that lived within the tidal zone of the seacoast. Thus, one more chapter is added to the early history of the animal world of the Earth.

Mrs. Elena Kleschenko | alfa
Further information:
http://www.informnauka.ru/eng/2002/2002-11-27-02_261_e.htm

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>