Ancient ecosystem is very similar to today's ecosystem

It is the world where the giant Anomalocaris cups meat of three-lobed beetles, contributing in that world to species that no longer exist on the earth today. But according to the researchers who made the first work to reconstruct the detailed food web of the ancient world, the ecosystem of the Cambrian century is quite modern.

Their article, published this week in the journal PLoS Biology, says that the network of interrelated feed relationships in the water hundreds of millions of years ago is quite similar to today.

Food webs describe interactions among species in a habitat. Food webs are similar to food chains but are more complex and practical. Exploring strict and eternal rules in the process of organizing food webs will help us understand the history and evolution of life. This will bring about an understanding of the modern ecosystem, such as how the ecosystem responds to the signals of the extinction process as well as the invasion of organisms.

A multidisciplinary team of scientists led by ecologist Jennifer Dunne of Santa Fe Institute in Santa Fe, New Mexico, coordinated with Pacific Ecoinformatics and Computational Ecology Laboratory in Berkeley, California to study the food webs of students Marine animals are preserved in the Cambrian century stones - the time of biodiversity explosion of multicellular species, including the predecessors of today's species and many strange creatures at the end of evolution. dead. The co-author of the article Richard Williams of the Microsoft Research Department (Cambridge, UK) has developed a 'Network3D' software to use in the process of analyzing and reproducing food webs.

Image of food web in the Burgress Shale area in the middle of the Cambrian.The spheres represent species or groups of species, the link between the spheres showing the relationship of food.In the figure is the top predator, the giant Anomalocaris, with one of its food species, the Olenoides three-lobed beetles.Arrows indicate their position in the food net.Many of the above structural features of the ancient ecosystem are similar to the modern food web structure.(Photo: ND Martinez; Food web created by Network3D software by RJ Williams. Drawings courtesy of Sam Gon III, www.trilobites.info.)

Researchers have collected data from the old 505 million-year-old Burgess Shale in British Columbia, Canada and Chengjiang Shale even in the eastern part of Yunna province, China dating back about 520 million years ago. Both of these locations are unusual in that they preserve both soft parts of a variety of species. They determine which species will eat the species by matching the clues. Sometimes they also obtained authentic evidence, such as intestinal fossils of carnivores, or cannibalistic priapulid worms Ottoia prolifica.However, in most cases, the relationship of food interaction is inferred from the living and body parts of the species. For example, claws, swimming lobes, big eyes, and jagged mouths indicate that the Anomalocaris canadensi - a large and unusual creature without modern descendants - is a fierce predator specializing in Eat three-lobed beetles and arthropods. The cut left on some fossils completely coincides with the Anomalocaris.

In order to compare the organization of the Cambrian ecology and the current ecosystem, the team used the method applied in network structure analysis, including methods to analyze the uncertainties obtained. from fossil data. Paleontologist and co-author Doug Erwin of the Santa Fe Institute and the Smithsonian Institute said: 'For a long time paleontologists have known that food webs are important but we lack the main methods. corpses to study food webs in ancient times. We have proven that we can reconstruct the ancient food web and compare it with today's food web, opening new avenues for the ecological ecology. We were surprised to find that most of the basic structural characteristics of the food web have been formed during the initial outbreak of animal life . '

The Cambrian food web has a lot in common with today's food net, such as the number of omnivorous species, the same carnivorous species involved with the distribution of the types of prey that each species has. Such rules, as well as any differences, are expressed only when changes in the number of species and links in the network are clearly explained. Dunne said: 'Interestingly, there is little difference between the ancient food web and the modern food web, especially in the food net in the Chengjiang Shale area. However, in general, the problem with species, or environment, or evolutionary history does not matter. There are still many types of food chains of the same type. '

Dunn adds: 'What we don't know is why the food webs in different habitats throughout history have so many rules. Perhaps species-level evolution has led to a stable community level model. For example, by limiting the number of species thanks to predators through selective pressure will cause extinction or increase the defenses of predator animals. Community models can reflect the long-term shape of many interacting species, or the fundamental natural restraint of the path through which resources flow through the ecosystem. '

The answers will bring new things at the intersection of ecology, evolution and physics. It may also provide valuable information for today's ecology. Williams points out that: 'This study is an excellent example reflecting the application of computerized methods in studies in certain industries to obtain new results. Understanding the ecosystem in the past helps us gain a deeper insight into what is happening to the ecosystem today and in the future. '

Quote: Dunne JA, Williams RJ, Martinez ND, Wood RA, Erwin DH (2008);Collection and analysis of Cambrian food webs;PLoS Biol 6 (4): e102.Do: 10.1371 / journal.pbio.0060102