Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




EARLY EARTH
Amphibians and dinosaurs were the new large predators after the mass extinction
by Staff Writers
Zurich, Switzerland (SPX) Mar 25, 2014


This is the fossil of Saurichthys, a top predator among the Triassic fishes. Image courtesy UZH.

252 million years ago the largest extinction event occurred at the end of the Permian age. It wiped out almost 90 percent of all life in water. So far researchers had assumed that the ecosystems gradually recovered from this catastrophe over a long stretch of eight to nine million years and that large predators at the uppermost end of the food chain were the last to reappear.

A Swiss-American team of palaeontologists headed by Torsten Scheyer and Carlo Romano from the University of Zurich demonstrate in their new study that the food nets during the Early Triassic did not recover in stages. Large predators like, for instance, crocodile-like amphibians and later the precursors of the known plesiosaurs and ichthyosaurs went in search of prey in the oceans soon after the end of the mass extinction.

Large predators in on the action from the very start
Apex predators - large predators at the uppermost end of the food chain - are extremely important for the health and stability of an ecosystem. They eradicate sick and weak animals and exercise constant selection pressure on the species they prey on. Hence, Scheyer and his colleagues wanted to establish whether the apex predators really were missing from the oceans after the mass extinction and how the ecosystems functioned.

The researchers looked at the global distribution of predatory marine vertebrates and their body size in the Early and Middle Triassic and came to surprising conclusions. "The apex marine predators recovered after the large extinction over a very, comparatively short period of time", says Torsten Scheyer.

The researchers were also able to refute a second theory. Earlier it had been assumed that marine predators grew continuously larger from the Early to the Middle Triassic culminating in the apex predators. "We now demonstrate that already in the Early Triassic large predators hunted in the seas", adds Carlo Romano.

"The length of the food chains was not shortened by the end-Permian mass extinction. Nor are there any signs of a gradual re-emergence of the classical trophic pyramids from the base to the top", explains Hugo Bucher. To gain greater understanding of food webs, attention had to be paid not only to the shape of the food webs but also to the dynamics, i.e. the evolutionary rates of the participating species.

New actors in old roles
The large end-Permian mass extinction led to a completely new composition of apex predators. Large predatory fish were dominant in the Permian age but they had to share this role with predatory crocodile-like amphibians after the mass extinction. Another extinction event around two million years later, the End Smithian crisis, triggered changes in the group of apex predators. From this point in time fish and for the first time reptiles like, for instance, Askeptosaurus were at the uppermost end of the food chains.

"The role of the large predators always remained the same in the ecosystems; only the actors changed over the course of time", comments Torsten Scheyer when summing up the new results. The researchers are convinced that insight into events in the past will contribute to better understanding of the impact of today's climate changes on ecosystems.

Torsten M. Scheyer, Carlo Romano, Jim Jenks, Hugo Bucher. Early Triassic Marine Biotic Recovery: The Predators' Perspective. PLOS ONE, March 19, 2014. DOI: 10.1371/journal.pone.0088987

.


Related Links
University of Zurich
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
Simulating how the Earth kick-started metabolism
Leeds UK (SPX) Mar 19, 2014
Researchers have developed a new approach to simulating the energetic processes that may have led to the emergence of cell metabolism on Earth - a crucial biological function for all living organisms. The research, which is published online in the journal Astrobiology, could help scientists to understand whether it is possible for life to have emerged in similar environments on other world ... read more


EARLY EARTH
Unique camera from NASA's moon missions sold at auction

NASA Releases First Interactive Mosaic of Lunar North Pole

China's Jade Rabbit lunar rover rouses from latest slumber

Study on lunar crater counting shows crowdsourcing effective, accurate tool

EARLY EARTH
NASA Orbiter Finds New Gully Channel on Mars

The Exploration of Murray Ridge Continues

Mars Reconnaissance Orbiter Resumes Full Duty

NASA Orbiter Safe After Unplanned Computer Swap

EARLY EARTH
Astronauts train at Maxwell

E3-production - sustainable manufacturing

TED turns 30 with new chapter of 'ideas worth spreading'

Orion Makes Testing, Integration Strides Ahead of First Launch to Space

EARLY EARTH
Tiangong's New Mission

"Space Odyssey": China's aspiration in future space exploration

China to launch first "space shuttle bus" this year

China expects to launch cargo ship into space around 2016

EARLY EARTH
New ISS Crew Wrapping Up Training for Launch

NASA Extends Lockheed Martin Contract to Support ISS

ESA astronaut Thomas Pesquet will fly to the ISS in 2016

How astronauts survive diplomatic tensions in space

EARLY EARTH
SpaceX Launch to the ISS Reset for March 30

NASA Awards Launch Services Contract for Solar Orbiter Mission

Ariane 5 hardware arrives for next ATV mission

Proton-M with two Russian communication satellites on board blasts off from Baikonur

EARLY EARTH
Space Sunflower May Help Snap Pictures of Planets

NRL Researchers Detect Water Around a Hot Jupiter

UK joins the planet hunt with Europe's PLATO mission

X-ray laser FLASH spies deep into giant gas planets

EARLY EARTH
ISS dodges space junk

Getting rid of bad vibrations

Pushing and pulling: Using strain to tune a new quantum material

Lightweight Construction Materials of Highest Stability Thanks to Their Microarchitecture




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.