The law of evolution is complex

Scientists have found evidence that the laws of evolution make animals more complex. Surveying fossils in the past 550 million years, the team observed different evolutionary branches of crustacean genealogies.

They are looking for examples of species in genealogy that have become simpler after their ancestors. Instead, they found that organisms with more and more complex characteristics and structures show that there is a mechanism that controls this directional change.

Dr. Matthew Wills of the Department of Biology and Biochemistry at Bath University, in collaboration with colleagues Sarah Adamowicz, University of Waterloo (Canada) and Andy Purvis, Royal University of London, said: 'If you come from an animal as simple as possible has only one direction to evolve - that is to become more complicated. '

Lobster lobster.In complex crustaceans like shrimp and lobster, almost every piece on the body is different, including jaw, jaw, leg, flippers and bibs.(Photo: iStockphoto / Tammy Peluso)

'However, sooner or later, you will reach a level of complexity from which to go back and become simpler. The surprising thing here is that almost no crustaceans go the opposite way. Instead, most branches choose an evolutionary direction: become more complex. "

'Of course, there are exceptions in crustaceans, but most of them are parasites or species that live in distant environments such as underwater isolation caves. Our new results show how the complex increase has occurred. What is remarkable is that this is more like a stereotypical march than a messy crowd. '

Dr Adamowicz said: 'Previous researchers have noticed an increase in morphological complexity in fossils, but this pattern occurs due to the accidental origination of some new species. Our work uses information about the relationship between different groups of animals - 'Tree of Life' - to illustrate complexity that evolved countless times independently. '

Like all arthropods, crustaceans are formed from repetitive fragments. In the simplest crustacean, these pieces are quite similar - one after the other. But in the most complex form, such as shrimp and lobster, almost every piece is different, including beards, jaws, legs, feet, flippers and bibs.

Dr. Wills said: 'The extinct crustaceans tend to be less complicated than the others at the same time. there is even a relationship between the average complexity in the group and the number of species that exist today. All living things share a common ancestor, so every living creature is a part of a giant family of life. '

Dr. Adamowicz added: 'With a few exceptions, once the branches of the genealogical tree split, they will continue to evolve independently. Observing many independent branches is similar to rewinding countless times an evolutionary tape. Our results apply to a group of animals whose bodies form from repetitive pieces. We must not forget that bacteria - very simple living things - are one of the most successful creatures. Therefore, the complex trend is convincing but does not capture the history of all life. '

This work was published in the Proceedings of the National Academy of Sciences .