Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




EARLY EARTH
Theory on origin of animals challenged: Animals needs only extremely little oxygen
by Staff Writers
Odense, Denmark (SPX) Feb 19, 2014


Sea sponge Halichondria panicea was used in the experiment at the University of Southern Denmark. Image couretsy Daniel Mills/SDU.

One of science's strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.

The origin of complex life is one of science's greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 - 635 million years ago.

However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.

In fact animals can live and grow when the atmosphere contains only 0.5 per cent of the oxygen levels in today's atmosphere.

"Our studies suggest that the origin of animals was not prevented by low oxygen levels", says Daniel Mills, PhD at the Nordic Center for Earth Evolution at the University of Southern Denmark.

Together with Lewis M. Ward from the California Institute of Technology he is the lead author of a research paper about the work in the journal PNAS.

A little over half a billion years ago, the first forms of complex life - animals - evolved on Earth. Billions of years before that life had only consisted of simple single-celled life forms. The emergence of animals coincided with a significant rise in atmospheric oxygen, and therefore it seemed obvious to link the two events and conclude that the increased oxygen levels had led to the evolution of animals.

"But nobody has ever tested how much oxygen animals need - at least not to my knowledge. Therefore we decided to find out", says Daniel Mills.

The living animals that most closely resemble the first animals on Earth are sea sponges. The species Halichondria panicea lives only a few meters from the University of Southern Denmark's Marine Biological Research Centre in Kerteminde, and it was here that Daniel Mills fished out individuals for his research.

"When we placed the sponges in our lab, they continued to breathe and grow even when the oxygen levels reached 0.5 per cent of present day atmospheric levels", says Daniel Mills.

This is lower than the oxygen levels we thought were necessary for animal life.

The big question now is: If low oxygen levels did not prevent animals from evolving - then what did? Why did life consist of only primitive single-celled bacteria and amoebae for billions of years before everything suddenly exploded and complex life arose?

"There must have been other ecological and evolutionary mechanisms at play. Maybe life remained microbial for so long because it took a while to develop the biological machinery required to construct an animal. Perhaps the ancient Earth lacked animals because complex, many-celled bodies are simply hard to evolve", says Daniel Mills.

His colleagues from the Nordic Center for Earth Evolution have previously shown that oxygen levels have actually risen dramatically at least one time before complex life evolved. Although plenty of oxygen thus became available it did not lead to the development of complex life. Read more about this work here.

.


Related Links
University of Southern Denmark
Explore The Early Earth at TerraDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EARLY EARTH
How evolution shapes the geometries of life
College Park MD (SPX) Feb 19, 2014
Why does a mouse's heart beat about the same number of times in its lifetime as an elephant's, although the mouse lives about a year, while an elephant sees 70 winters come and go? Why do small plants and animals mature faster than large ones? Why has nature chosen such radically different forms as the loose-limbed beauty of a flowering tree and the fearful symmetry of a tiger? These quest ... read more


EARLY EARTH
Lunar ownership laws: a future necessity?

Chang'e-2 lunar probe travels 70 mln km

LADEE Sends Its First Images of the Moon Back to Earth

Source of 'Moon Curse' Revealed by Eclipse

EARLY EARTH
NASA Mars Orbiter Views Opportunity Rover on Ridge

Curiosity Adds Reverse Driving for Wheel Protection

Curiosity Drives On After Crossing Martian Dune

The World Above and Beyond

EARLY EARTH
Orion Underway Recovery Testing Begins off the Coast of California

Inside astronaut Alexander's head

NASA Welcomes University Participants to Develop Science Payloads

Boeing Commercial Crew Program Passes NASA Hardware, Software Reviews

EARLY EARTH
No Call for Yutu

What's up, Yutu

China's Jade Rabbit rover comes 'back to life'

Yutu Awakes

EARLY EARTH
NASA, International Space Station Partners Announce Future Crew Members

Andrews Space Cargo Module Power Unit Provides Power For Payloads Bound For ISS

Russian Progress M-22M docks with ISS following fast rendezvous

Russian Resupply Spacecraft Begins Expedited Flight to Station

EARLY EARTH
Arianespace to launch OPTSAT 3000 and VENuS satellites

Amazonas 4A is prepared for Arianespace's second Ariane 5 flight of 2014

New Russian Rocket Mock-Up Rolls Out to Launch Pad

Lighter engines a headache for satellite launcher Ariane

EARLY EARTH
Scientist: Exoplanet research needs less hype, more patience

Europe sets plans for 2024 planet-hunting mission

ESA selects planet-hunting PLATO mission

Rife with hype, exoplanet study needs patience and refinement

EARLY EARTH
Physicists produce a potentially revolutionary material

ASC Signal Selected by Newtec to Provide Transmit Receive Satellite Antennas for Pan-European Network

It's alive! Bacteria-filled liquid crystals could improve biosensing

Ancient helium rising to the surface in Yellowstone National Park




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.