Navigation Links
First fruitful, then futile: Ammonites or the boon and bane of many offspring
Date:4/23/2012

For 300 million years, they were the ultimate survivors. They successfully negotiated three mass extinctions, only to die out eventually at the end of the Cretaceous along with the dinosaurs: Ammonoids, or ammonites as they are also known, were marine cephalopods believed to be related to today's squid and nautiloids. Ammonoids changed their reproductive strategy early on in the course of evolution. However, what was once a successful initial strategy may well have proved to be a fatal boomerang at the end of the Cretaceous, as an international team of researchers headed by paleontologists from the University of Zurich demonstrate in a study recently published in the science journal Evolution.

Embryos already had coiled shells

At the beginning of their evolution, ammonoids had straighter shells, which, like other mollusks, they began to coil during the Devonian Period. The precise reason behind this change is unknown. The selection pressure in favor of more tightly coiled shells is believed to have sprung from the ammonoids' natural predators. As the scientists have now discovered, the shell change also affected the ammonoid embryos. "In the oldest ammonoids, the embryonic shells were considerably bigger and coiled less tightly than in later forms," explains Kenneth De Baets, a paleontologist at the University of Zurich, summing up the latest findings.

Smaller hatchlings, more offspring

There were two more evolutionary trends that coincided with the increasingly more tightly coiled shells: The size of the embryonic shells shrank increasingly over time the hatchlings became smaller and smaller. In parallel, the shell size of fully grown animals increased and, on the whole, the animals became increasingly bigger. Based on this, the researchers deduced that the number of offspring in ammonoids rocketed during the Devonian Period. This is confirmed by discoveries of substantial clusters of fossilized embryonic shel
'/>"/>

Contact: Kenneth Da Baets
kenneth.debaeats@pim.uzh.ch
41-446-342-347
University of Zurich
Source:Eurekalert  

Page: 1 2

Related biology news :

1. Putting plants online: 4 leading botanical gardens to create first online catalog of all plants
2. ORNL microscopy yields first proof of ferroelectricity in simplest amino acid
3. First description of a triple DNA helix in a vacuum
4. Scientists complete first-ever emperor penguin count from space
5. First mass extinction linked to marine anoxia
6. New technology tracks sparrow migration for first time from California to Alaska
7. FirstMark Exhibiting at the Inaugural Atlanta Clinical Cardiology Update
8. FirstMark Announces New Hire Jay Houtman as Southeast Regional Sales Manager
9. First complete full genetic map of promising energy crop
10. Ottawa researchers to lead world-first clinical trial of stem cell therapy for septic shock
11. American College of Rheumatology releases first classification criteria for polymyalagia rheumatica
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
First fruitful, then futile: Ammonites or the boon and bane of many offspring
(Date:11/18/2014)... 2014   EyeLock Inc. , a market ... MorphoTrust USA (Safran), a leading U.S. provider ... strategic partnership to offer comprehensive biometric identity solutions ... airport screening and financial services markets. ... consumers through a nationwide network of 1,100 IdentoGO® ...
(Date:11/12/2014)... , Nov. 12, 2014 Crossmatch™, a ... that its U.are.U ® fingerprint readers have been ... in Central Mexico . The bakery ... to eliminate payroll issues caused by employees clocking in ... the U.are.U fingerprint readers, Montparnasse relied on paper timecards ...
(Date:11/10/2014)... Laundry detergent pods began appearing on U.S. store shelves ... growing numbers ever since. The small packets can be ... measure out a liquid or powder. The convenience, though, ... new study from researchers at Nationwide Children,s Hospital found ... received reports of 17,230 children younger than 6 years ...
Breaking Biology News(10 mins):EyeLock, MorphoTrust Form Strategic Partnership to Pursue Commercial Enterprise Deployments 2EyeLock, MorphoTrust Form Strategic Partnership to Pursue Commercial Enterprise Deployments 3Montparnasse Pasteleria Achieves Time and Attendance Transparency with Crossmatch U.are.U Fingerprint Readers 2Study finds laundry detergent pods, serious poisoning risk for children 2
... release is available in German . ... and oxygen in order to survive. For this reason, a tumour ... to the blood circulation. In doing this, it is supported by ... neutrophils, which are supposed to protect the body against pathogens. ...
... poisoning in the news, including a recent event that led ... drives home the need for better bacterial detection long before ... the horizon is a new approach for pathogen screening that ... the technique in the ACS journal Analytical Chemistry . ...
... Nutrition Research Centre (CNRC) -- a $20 million ... (A*STAR) and National University Health Systems (NUHS) -- ... conduct nutritional studies to understand the causes of metabolic ... and formulate diets that can reduce the risks of ...
Cached Biology News:Jamming in tumors 2Asia's first under-1-roof Nutritional Research Centre set up in Singapore 2Asia's first under-1-roof Nutritional Research Centre set up in Singapore 3Asia's first under-1-roof Nutritional Research Centre set up in Singapore 4
(Date:12/19/2014)... 2014 LayerBio is an MIT spin-off ... care. The National Eye Institute (NEI) at the National ... I SBIR grant to develop a drug-eluting intraocular lens ... common cause of vision loss in people over age ... to Dr. Ken Mandell, LayerBio’s Founder and CEO, "There ...
(Date:12/19/2014)... December 19, 2014 In contrast to ... LEDs with various colors, Valoya uses proprietary LED technology ... offers best possible uniformity which is critical in low ... high spectral accuracy throughout its lifetime which is up ... tubes. , "The investment cost was clearly higher ...
(Date:12/19/2014)... 2014 Egenix, Inc. is pleased to announce that ... the Board, to succeed Donald Fresne ; Mr. Fresne ... as a member of the Board.  In recognition of the ... company over almost twenty years, the Board designated Mr. Fresne ... has established a Search Committee to find a suitable replacement ...
(Date:12/17/2014)... Based on the revenues gained from surgical imaging ... by four major players contributing to approximately 74% ... GE Healthcare (U.K.), Siemens AG (Germany), Philips (Netherlands), ... Copy at http://www.marketsandmarkets.com/Market-Reports/surgical-imaging-market-210534462.html , The leading ... its strong product portfolio, which includes its flagship ...
Breaking Biology Technology:LayerBio Awarded NIH Grant to Develop a Drug Delivery Device for Cataract Surgery 2Global Refurbished Surgical Imaging Market by Product & Application is Estimated to Reach $1.25 Billion by 2019 - New Research Report by MarketsandMarkets 2Global Refurbished Surgical Imaging Market by Product & Application is Estimated to Reach $1.25 Billion by 2019 - New Research Report by MarketsandMarkets 3Global Refurbished Surgical Imaging Market by Product & Application is Estimated to Reach $1.25 Billion by 2019 - New Research Report by MarketsandMarkets 4
... Committee Recommendation in European UnionSAN MATEO, Calif., March 19 ... biopharmaceutical company focused on developing and commercializing novel pain ... call on Friday, March 20, 2009 at 9:00 a.m. ... year-end 2008 results and the European Medicines Agency,s (EMEA) ...
... Solutions, a global life sciences technology solutions company ... that one of the world,s largest pharmaceutical companies ... System. This system provides a powerful, flexible ... lifecycle... from proposal to publication... helping to ensure ...
... will allow the recycling and conversion of 60% ... 19 /PRNewswire/ - Enerkem Inc., a leading advanced ... its plans to build and operate a second-generation ... In addition, the company announced the signature of ...
Cached Biology Technology:NeurogesX to Hold Conference Call to Discuss Fourth Quarter and Year-End 2008 Financial Results and European Regulatory Update 2NeurogesX to Hold Conference Call to Discuss Fourth Quarter and Year-End 2008 Financial Results and European Regulatory Update 3NeurogesX to Hold Conference Call to Discuss Fourth Quarter and Year-End 2008 Financial Results and European Regulatory Update 4Top Ten Pharma Company Deploys MedNet Solutions' Investigator Initiated Trial Management System 2Enerkem announces plans to enter the United States with next-generation biofuels project in Mississippi 2Enerkem announces plans to enter the United States with next-generation biofuels project in Mississippi 3
... Peptide microarrays containing peptidomimetics built on ... on-chip synthesis platform. These microarrays are ... Custom Peptide Microarray Service. ... is completely customer specified. Thousands of ...
... are custom designed to meet your needs. ... 8,455 features per array (2 arrays/1" x ... array (1 array/slide). Features ... - This extended length delivers higher sensitivity ...
... Chemicon Select Tissue Arrays are intended ... individual tissues were fixed in neutral buffered ... identification and diagnosis was performed by certified ... their paraffin blocks and relocated into a ...
... Chemicon Select Tissue Arrays are intended for ... tissues were fixed in neutral buffered formalin ... and diagnosis was performed by certified pathologists. ... paraffin blocks and relocated into a new ...
Biology Products: