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  

0

GOOD

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:5/24/2013)... , Cancer cells spread and grow by avoiding ... the immune system can help to eliminate cancer cells; ... system to ignore cancer cells. Regulatory T cells are ... response. In this issue of the Journal of ... Stanford University found that regulatory T cells that infiltrate ...
(Date:5/24/2013)... leading water scientists from around the world today issued ... short span of one or two generations, the majority ... living under the handicap of severe pressure on fresh ... is no substitute. This handicap will be self-inflicted and ... pointed to chronic underlying problems led by mismanagement and ...
(Date:5/23/2013)... Health at Emory University, along with partners at ... $4 million grant over four years to establish ... Exposome Research Center: Understanding Lifetime Exposures). The grant ... the United States. , The HERCULES Center ... Health Sciences (NIEHS) of the National Institutes of ...
Breaking Biology News(10 mins):JCI early table of contents for May 24, 2013 2JCI early table of contents for May 24, 2013 3JCI early table of contents for May 24, 2013 4JCI early table of contents for May 24, 2013 5JCI early table of contents for May 24, 2013 6JCI early table of contents for May 24, 2013 7JCI early table of contents for May 24, 2013 8A majority on Earth face severe self-inflicted water woes within 2 generations: Scientists 2A majority on Earth face severe self-inflicted water woes within 2 generations: Scientists 3A majority on Earth face severe self-inflicted water woes within 2 generations: Scientists 4Emory, Georgia Tech receive first human exposome center grant in US 2Emory, Georgia Tech receive first human exposome center grant in US 3
... Chinese government regulators had clearer skies and easier breathing ... temporarily shuttered some factories and banished many cars in ... that,s what they got. They were not ... satellites to measure the impact of air pollution controls. ...
... The first fuel-handling facility in the Galpagos ... given official environmental certification today, World Wildlife Fund ... in order to meet certification standards, which are ... and Toyota, in conjunction with the Ecuadorian Government, ...
... the University of Illinois and the University of Massachusetts ... bacteria,s evolutionary machinery into programming its own death. ... something in a bacteria that, in order to gain ... a suicide mutation," said Gerard Wong, a professor of ...
Cached Biology News:New satellite data reveal impact of Olympic pollution controls 2New satellite data reveal impact of Olympic pollution controls 3First fuel-handling facility in the Galapagos earns environmental certification 2Scientists fool bacteria into killing themselves to survive 2
(Date:5/24/2013)... Quincy Bioscience, a leading research ... calcium-binding proteins to support healthy living, is pleased ... of apoaequorin in Food and Chemical ... British Industrial Biological Research Association. , The ... adverse effects, if any, of apoaequorin, in rats ...
(Date:5/23/2013)... 2013  BioScrip, Inc. (NASDAQ: BIOS ) ... Jefferies 2013 Global Healthcare Conference to be held June ... Richard Smith , President and ... , Chief Financial Officer, will present on Monday, June ... About BioScrip BioScrip, Inc. provides comprehensive ...
(Date:5/23/2013)... , May 23, 2013 PuraMed BioScience ... and marketer of over-the-counter (OTC) medicinal and healthcare ... opinion on the company based on low market ... , Non-Prescription, All Natural Product to Treat Migraine ... Outperforms #1 Prescription Competitor , Currently Available ...
(Date:5/23/2013)... MARINO, Calif. , May 23, 2013 /PRNewswire/ ... today a strategic alliance with DAK Renewable Research ... the corn oil yield. VG Energy is a ... (OTC Pink: VGLS). VG Energy,s exclusively ... to increase the oil yield in plants, possessing ...
Breaking Biology Technology:Safety Assessment Study of Apoaequorin Published in Food and Chemical Toxicology 2PuraMed BioScience (PMBS) Issued Alert Based on Market Cap of $721,756 2PuraMed BioScience (PMBS) Issued Alert Based on Market Cap of $721,756 3VG Energy Enters into a Strategic Alliance with DAK Renewable Research for LipidMax Field Trials 2VG Energy Enters into a Strategic Alliance with DAK Renewable Research for LipidMax Field Trials 3
... 4, 2010 Onda Corporation, the global leader in ... the latest additions to the hydrophone product family at ... is a new fiber optic hydrophone system that can ... applications of HITU. It is complemented with the release ...
... Consulting , a business unit of PAREXEL International (Nasdaq: ... serving the biopharmaceutical and medical device industries, today announced ... U.S. Food and Drug Administration’s (FDA) International Compliance Branch, ... its Strategic Compliance Services team, reporting directly to the ...
... - Scientists at the U.S. Department of Energy,s (DOE) ... fabricated transparent thin films capable of absorbing light and ... material, described in the journal Chemistry of Materials ... or even windows that absorb solar energy to generate ...
Cached Biology Technology:Onda Introduces a New Fiber Optic Hydrophone and Scanning Tank 2Edwin Rivera-Martinez, Former Chief of the FDA’s International Compliance Branch, Joins PAREXEL Consulting Strategic Compliance Team 2Edwin Rivera-Martinez, Former Chief of the FDA’s International Compliance Branch, Joins PAREXEL Consulting Strategic Compliance Team 3Edwin Rivera-Martinez, Former Chief of the FDA’s International Compliance Branch, Joins PAREXEL Consulting Strategic Compliance Team 4Edwin Rivera-Martinez, Former Chief of the FDA’s International Compliance Branch, Joins PAREXEL Consulting Strategic Compliance Team 5Edwin Rivera-Martinez, Former Chief of the FDA’s International Compliance Branch, Joins PAREXEL Consulting Strategic Compliance Team 6Transparent conductive material could lead to power-generating windows 2
Glucagon-like peptide-1 (GLP-1 (1-36) amide)...
... LC Sciences provides a comprehensive microarray ... regulatory/functional RNA embedded within non-coding RNAs ... and proprietary probe design, which enables ... of small RNAs (1). This comprehensive ...
... LC Sciences provides a comprehensive ... protein kinase substrate (PKS) peptide microarrays ... proteomic scale kinase profiling, quantitative measurement ... discovery research. This comprehensive service includes ...
... Sciences provides a unique new tool, OligoMix ... serving diverse needs in genomics, proteomics, synthetic ... is a MIXTURE of a large number ... in a single microtube. OligoMix is made ...
Biology Products: