Navigation Links
Study reveals predation-evolution link
Date:9/10/2007

Blacksburg, Va. -- The fossil record seems to indicate that the diversity of marine creatures increased and decreased over hundreds of millions of years in step with predator-prey encounters, Virginia Tech geoscientists report in the Proceedings of the National Academy of Science.

For decades, there has been a debate between paleontologists, biologists, and ecologists on the role of ecological interactions, such as predation, in the long term patterns of animal evolution.

John Warren Huntley, a postdoctoral scientist in the Department of Geosciences at Virginia Tech, and Geosciences Professor Micha Kowalewski decided to look at the importance of ecology by surveying the literature for incidents of predation in marine invertebrates, such as clams and their relatives.

Today, certain predators leave easy to identify marks on the shells of their prey, such as clean, round holes, said Huntley. Such holes drilled by predators can also be found in fossil shells.

The researchers also looked for repair scars on the shells of creatures that survived an attack.

The study was conducted by looking at studies which reported the frequency of drill holes and repair scars in fossil species from the last 550 million years.

First Huntley and Kowalewski found that predation increased notably about 480 million years ago, some 50 million years earlier than previous studies have found. The earlier studies were based on changes in morphology predators with stronger claws and jaws and prey with more ornamented shells. We looked at the frequency of attacks, which increased about 50 million years before the changes in armor, said Huntley.

But the most notable discovery is the observation that the incidence of drill holes and repair scars are strikingly parallel to Sepkoskis diversity curve for marine invertebrates. This diversity curve, compiled by the late Jack Sepkoski of the University of Chicago, records the origination and extinction of marine animal genera through the last 540 million years (Phanerozoic). There is a strong correlation between predation intensity and global marine biodiversity in the Phanerozoic, Huntley said.

In their article, Strong Coupling of Predation Intensity and Diversity in the Phanerozoic Fossil Record, the researchers offer three rival hypotheses to explain the correlation. Its the classic problem with interpreting a correlation, said Huntley you have to be careful when ascribing a cause. Lets say factors X and Y are correlated. A change in X could cause a change in Y, a change in Y could cause a change in X, or X and Y could both be controlled by another factor.

The first hypothesis is that predation intensity could be driving diversity. In this case, ecological interactions would matter in evolution, said Huntley. Organisms evolve over the long term in response to their enemies, and with increased predation intensity more species evolve.

The second hypothesis is that as biodiversity increased, by chance predators with more complex feeding strategies evolved. Predatory techniques like drilling and peeling shells are more evolutionarily-derived than more primitive forms of predation like whole ingestion. In this scenario you would expect to evolve sophisticated forms of predation only when diversity is high, said Huntley.

And the third hypothesis is that something else is driving both predation and biodiversity. Some periods have more sedimentary rocks, and therefore more fossils, preserved than others, said Huntley. There is less diversity to be observed when there are fewer fossils to study. Perhaps this sampling bias affects our ability to find samples with high predation intensities as well.

Now we will try to pick this apart, said Huntley. We can test these hypotheses by examining relevant linkages between predation intensity and diversity in modern oceanic environments. Also, understanding the true nature of Sepkoskis curve will help us interpret our findings. Is it biological" Is it the product of uneven sampling"


'/>"/>

Contact: Susan Trulove
strulove@vt.edu
540-231-5646
Virginia Tech
Source:Eurekalert

Related biology news :

1. Bioartificial kidney under study at MCG
2. Novel Asthma Study Shows Multiple Genetic Input Required; Single-gene Solution Shot Down
3. W.M. Keck Foundation funds study of friendly microbes
4. Yellowstone microbes fueled by hydrogen, according to U. of Colorado study
5. Emory Study Tests Bone Marrow Stem Cells to Improve Circulation in Legs
6. UCLA Study Shows One-Third of Drug Ads in Medical Journals Do Not Contain References Supporting Medical Claims
7. Study Demonstrates Gene Expression Microarrays are Comparable and Reproducible
8. Study Links Ebola Outbreaks To Animal Carcasses
9. Genome-wide mouse study yields link to human leukemia
10. Breakthrough Microarray-based Technology for the Study of Cancer
11. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/28/2016)... First quarter 2016:   , Revenues amounted ... quarter of 2015 The gross margin was 49% (27) ... the operating margin was 40% (-13) Earnings per share ... operations was SEK 249.9 M (21.2) , Outlook   ... M. The operating margin for 2016 is estimated to ...
(Date:4/15/2016)... -- Research and Markets has announced the ...  report to their offering.  ,      ... gait biometrics market is expected to grow at ... Gait analysis generates multiple variables such ... compute factors that are not or cannot be ...
(Date:3/29/2016)... 2016 LegacyXChange, Inc. (OTC: ... SelectaDNA/CSI Protect are pleased to announce our successful effort ... variety of writing instruments, ensuring athletes signatures against counterfeiting ... from athletes on LegacyXChange will be assured of ongoing ... Bill Bollander , CEO states, "By ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016 Apellis Pharmaceuticals, Inc. today ... trials of its complement C3 inhibitor, APL-2. The ... ascending dose studies designed to assess the safety, ... injection in healthy adult volunteers. Forty ... a single dose (ranging from 45 to 1,440mg) ...
(Date:6/23/2016)... ... June 23, 2016 , ... Regulatory Compliance Associates® Inc. (RCA), ... free webinar on Performing Quality Investigations: Getting to Root Cause. ... no charge. , Incomplete investigations are still a major concern to the Regulatory ...
(Date:6/22/2016)... 2016 Research and Markets has announced the ... to their offering. The ... $29.3 billion in 2013. The market is expected to grow at ... to 2020, increasing from $50.6 billion in 2015 to $96.6 billion ... the forecast period (2015 to 2020) are discussed. As well, new ...
(Date:6/22/2016)... ... June 21, 2016 , ... New light-based technologies that facilitate a “look inside” ... to enable both compact, wearable devices for point-of-care diagnostics as well as powerful new ... Recent work and visionary future directions are detailed in a new open-access article by ...
Breaking Biology Technology: