Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Break Down Patterns in Nature

15.04.2003



Nature has many patterns and ecologists seek to both describe and understand them. Nature also is very complex. One challenge is to find patterns in that complexity and to ask whether simple explanations lie beneath them.

Ecologists have tackled this challenge for decades, erecting various hypotheses and debating their plausibility. In an important paper featured in the current issue of the Proceedings of the National Academy of Sciences (PNAS), an international team of ecologists describes a fundamental theory that unites several patterns that previously had been viewed as unrelated.

The theory simplifies various aspects of ecological complexity with an elegant model that unites all of them. It provides a theory for quantifying biodiversity.




George Sugihara of Scripps Institution of Oceanography, UCSD, (USA) led a team that included Lord Robert May and Sir Richard Southwood of Oxford University (United Kingdom), Louis-Félix Bersier of the University of Neuchâtel (Switzerland), and Stuart Pimm of Duke University (USA).

The first pattern they considered involves the relationships between various roles played by the species present in an area (their niches). These relationships are often described in ecology as something akin to an "evolutionary tree" in which the branches reflect how ecological communities are organized—a tree-like organizational chart of ecological roles. One "branch" might be all those bird species that feed on insects, another "branch" those species that feed on seeds.

From these main branches, different small branches might be the various insect-feeding species that glean insects from leaves (such as warblers) or bark (such as nuthatches), or those species that catch insects in flight (such as flycatchers). As niches are specified more exactly, we move to the "terminal twigs" in the analogy: the individual species themselves. One "twig" might be a particular bird that gleans insects from the top leaves of a tree, another twig the different species that glean insects from the bottom leaves.

Sugihara and his colleagues found that these common representations have far more information in them than was previously recognized. The pair of species in the terminal twigs have a relationship to each other—they are splitting up the resource that is the total of the insects feeding on the tree.

The PNAS paper finds that abundances of pairs of species in terminal twigs behave in a very special way. "Just like two pieces of rock that once belonged together," Pimm says. "Take a rock and split it into two pieces. On average, the bigger piece will be three-quarters of the rock, the smaller a quarter of the rock. If you take any two rocks, there won’t be such a pattern. The sizes of those rocks are unrelated."

The paper shows that this applies to all the branches in the tree: such as the total abundance of all seed-eating birds versus the total abundance of insect-eating birds.


What can you do with this insight? Plenty, Sugihara argues. "For one thing, a species represented by a ‘twig’ should be much less common than a species that is represented by a ‘branch,’" says Sugihara. "A bird that feeds on small insects from leaves on the top of a tree should be rarer than one that can feed on all sizes of insects anywhere. That prediction holds up."

It can apply to human niches too: The more specialized a profession, the fewer customers the business will have. A general store usually caters to more customers than one that sells just one kind of product.

The insight also suggests a pattern to species abundances across many species. It’s the exact pattern one would get from breaking a rock once, then picking one of the pieces and splitting it, then picking another piece and splitting it, and so on. That sequential splitting generates a characteristic pattern in the sizes of rocks—and the abundance of species. It’s also exactly the one we observe in nature.

In short, Sugihara and colleagues have produced a fundamental theory of the patterns of nature free from any numbers that have to be estimated. (It’s "parameter-free" in scientific jargon—a holy grail in science). The logical consequences of the idea have surprising explanatory power.

There is another extension to these ideas that has been known for some time, but for which Sugihara’s group provides a firm anchor. Suppose we try to place those rock pieces in a sieve. Some will be so small they will pass through the sieve. Hitting the rock more often doesn’t give us more pieces, for we just lose more through the cracks. So it is with species: some become too rare to survive. The bigger the rock, the more pieces we can have before we start to lose them.

Of course, human impacts are shrinking the rock in this metaphor—diminishing the resources available to all species.

Shrink the rock and, as long as you keep sequentially breaking it, you reduce the species in a precise mathematical way. This happens to be exactly the way species drop out as human actions diminish the world by shrinking the habitats (such as tropical forests) on which species depend.

The study was supported by the Office of Naval Research, Merton College Oxford University, the Swiss National Science Foundation, Novartis Foundation, and the Leverhulme Trust.

Mario Aguilera | Scripps News
Further information:
http://scrippsnews.ucsd.edu/pressreleases/sugihara-PNAS.html

More articles from Ecology, The Environment and Conservation:

nachricht Emissions from road construction could be halved using today’s technology
18.05.2020 | Schwedischer Forschungsrat - The Swedish Research Council

nachricht When every particle counts: IOW develops comprehensive guidelines for microplastic extraction from environmental samples
11.05.2020 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

Black nitrogen: Bayreuth researchers discover new high-pressure material and solve a puzzle of the periodic table

29.05.2020 | Materials Sciences

Argonne researchers create active material out of microscopic spinning particles

29.05.2020 | Materials Sciences

Smart windows that self-illuminate on rainy days

29.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>