In a study published in the Proceedings of the National Academy of Sciences researchers have found evidence which suggests that evolution drives animals to become increasingly more complex.
Looking back through the last 550 million years of the fossil catalogue to the present day, the team investigated the different evolutionary branches of the crustacean family tree.
They were seeking examples along the tree where animals evolved that were simpler than their ancestors.
Instead they found organisms with increasingly more complex structures and features, suggesting that there is some mechanism driving change in this direction.
“If you start with the simplest possible animal body, then there’s only one direction to evolve in – you have to become more complex,” said Dr Matthew Wills from the Department of Biology & Biochemistry at the University of Bath who worked with colleagues Sarah Adamowicz from from the University of Waterloo (Canada) and Andy Purvis from Imperial College London.
“Sooner or later, however, you reach a level of complexity where it’s possible to go backwards and become simpler again.
“What’s astonishing is that hardly any crustaceans have taken this backwards route.
“Instead, almost all branches have evolved in the same direction, becoming more complex in parallel.
“This is the nearest thing to a pervasive evolutionary rule that’s been found.
“Of course, there are exceptions within the crustacean family tree, but most of these are parasites, or animals living in remote habitats such as isolated marine caves.
“For those free-living animals in the ‘rat-race’ of evolution, it seems that competition may be the driving force behind the trend.
“What’s new about our results is that they show us how this increase in complexity has occurred.
“Strikingly, it looks far more like a disciplined march than a milling crowd.”
Dr Adamowicz said: “Previous researchers noticed increasing morphological complexity in the fossil record, but this pattern can occur due to the chance origination of a few new types of animals.
“Our study uses information about the inter-relatedness of different animal groups – the ‘Tree of Life’ – to demonstrate that complexity has evolved numerous times independently.”
Like all arthropods, crustaceans’ bodies are built up of repeating segments. In the simplest crustaceans, the segments are quite similar - one after the other. In the most complex, such as shrimps and lobsters, almost every segment is different, bearing antennae, jaws, claws, walking legs, paddles and gills.
The American biologist Leigh Van Valen coined the phrase ‘Red Queen’ for the evolutionary arms race phenomenon. In Through the Looking-Glass Lewis Carroll’s Red Queen advises Alice that: “It takes all the running you can do, to keep in the same place.”
“Those crustacean groups going extinct tended to be less complex than the others around at the time,” said Dr Wills.
“There’s even a link between average complexity within a group and the number of species alive today.
“All organisms have a common ancestor, so that every living species is part of a giant family tree of life.”
Dr Adamowicz added: “With a few exceptions, once branches of the tree have separated they continue to evolve independently.
“Looking at many independent branches is similar to viewing multiple repeated runs of the tape of evolution.
“Our results apply to a group of animals with bodies made of repeated units. We must not forget that bacteria – very simple organisms – are among the most successful living things. Therefore, the trend towards complexity is compelling but does not describe the history of all life.”
Andrew McLaughlin | alfa
Molecular microscopy illuminates molecular motor motion
26.07.2017 | Penn State
New virus discovered in migratory bird in Rio Grande do Sul, Brazil
26.07.2017 | Fundação de Amparo à Pesquisa do Estado de São Paulo
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
26.07.2017 | Physics and Astronomy
26.07.2017 | Life Sciences
26.07.2017 | Earth Sciences