Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Alligators hint at what life may have been like for dinosaurs

20.04.2009
During the last 540 million years, the earth's oxygen levels have fluctuated wildly.

Knowing that the dinosaurs appeared around the time when oxygen levels were at their lowest at 12%, Tomasz Owerkowicz, Ruth Elsey and James Hicks wondered how these monsters coped at such low oxygen levels.

But without a ready supply of dinosaurs to test their ideas on, Owerkowicz and Hicks turned to a modern relative: the alligator. 'We knew testing the effects of different oxygen levels would work with alligators,' Owerkowicz explains, 'because crocodilians have survived in their basic shape and form for 220 million years.

They must be doing something right to have survived the oxygen fluctuations.' Choosing to start at the beginning of alligator development, the trio decided to try incubating alligator eggs at different oxygen levels, to find out how the youngsters grew and developed and publish their results on April 17 2009 in The Journal of Experimental Biology at http://jeb.biologists.org.

Receiving newly laid alligator eggs from Elsey at the Rockefeller Wildlife Refuge, Owerkowicz divided the eggs into groups incubated at 12% (low) oxygen, 21% (normal) oxygen and 30% (high) oxygen, and waited to see what would happen. After almost 10 weeks of waiting, the eggs began hatching and Owerkowicz could see that there were no obvious differences between the alligators that developed in normal and high oxygen atmospheres.

But he was in for a shock when the low oxygen level hatchlings began to emerge. The tiny alligators' bellies were enormously swollen. They had failed to absorb all of the egg yolk food supply, leaving them with huge yolk-distended bellies. In some cases the bellies were so big that the animals' legs could not reach the ground, and the alligators had to sit around until they had burned off the yolk and could begin moving. Owerkowicz suspects that there was not enough oxygen for the developing embryos to consume the yolk. The low oxygen level youngsters' organs were much smaller too, all except the heart, which was relatively large, presumably to maximise use of the youngsters' limited oxygen supplies. Owerkowicz admits that he had thought that the low oxygen newborns' lungs would also be enlarged, to compensate for the poor oxygen supply, but they were not, probably because the incubating youngsters do not use their lungs and instead obtain their oxygen through blood vessels in the egg's membrane.

Next Owerkowicz was curious to see how the alligators performed after 3 months in their respective atmospheres. Checking the reptiles' breathing and metabolic rates, it was clear that the animals in the high oxygen atmosphere were breathing much less than the normal and low oxygen animals, probably because animals in the 30% oxygen atmosphere breathe in more oxygen per lungful, translating into a significant energy saving, which the reptiles could invest in growth. And when Owerkowicz checked the size of the 3 month old low oxygen youngsters' lungs, he could see that they had caught up with his expectations and were larger than those of the normal oxygen alligators. The alligators' lungs were enlarged to compensate for the low oxygen supply, allowing the alligators to increase their metabolic rates, but not as much as the normal or high oxygen alligators.

Owerkowicz admits that although his results can't tell us what life was like for his alligators' prehistoric predecessors, it is clear that 'their growth and metabolic patterns would have been significantly different,' he says.

Kathryn Knight | EurekAlert!
Further information:
http://www.biologists.com

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

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

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>