It seems that the evolutionary tree of life looks more like a giant swirling lollipop. Scientists have assembled the largest and most accurate timeline of life on Earth containing more than 50,000 different species. The new TimeTree of Life, as it is known, has revealed that rather than expanding in bursts, the diversity of life on our planet has actually been growing at a constant rate. Scroll down for video . This new TimeTree of 50,632 species was created by compressing evolutionary history into a narrow grey strip so that time progresses across the width of the strip. The different colours correspond to the main taxonomic divisions that appeared on Earth to create this lollipop, or spiral galaxy, shaped evolutionary tree . The finding contradicts the prevailing view of diversification slowing down as ecological niches fill up with species, only to surge forward again in the wake of a major extinction. Researchers also found that on average it takes around two million years for a new species to emerge from an existing group of animals. A study has claimed that the changes induced by evolution can be reversible, meaning certain animals can return to an earlier biological trait. The remarkable discovery was made by finding birds had regrown a bone previously discarded by dinosaurs millions of years ago. The study was carried out by a team of scientists from the University of Chile . They found that 230 million years ago, two-legged dinosaurs no longer required the strong wrists of their four-legged brethren, and thus they became weak. The number of bones in wrists shrank from 11 to three, with one in particular of interest to disappear being the pisiform. But according to the research, the bone reappeared when dinosaurs evolved into birds and took flight. The new bone, called the ulnare, appears in the same place as the pisiform once did. The pisiform allowed bird wings to remain rigid on the upstroke. The study found it disappeared in bird-like dinosaurs, but modern birds later evolved to once again use this tiny bone. The scientists used data from nearly 2,300 studies examining the molecular biology and genetic diversity of different species. They have now produced a database that can be searched to find out when species separated in evolutionary history and when they last shared a common ancestor. Professor Blair Hedges, director of the Centre for Biodiversity at Temple University in Philadelphia who was one of those leading the study, said the resulting tree took on a more spiral-like appearance. He said: 'This finding shows that speciation is more clock-like than people have thought. 'The constant rate of diversification that we have found indicates that the ecological niches of life are not being filled up and saturated. 'This is contrary to the popular alternative model which predicts a slowing down of diversification as niches fill up with species.' The researchers, whose study is published in the journal Molecular Biology and Evolution, used what are known as molecular-clocks to produce the new swirling tree of life. These look for changes within DNA to calculate the mutation rate and so the time it took for species to evolve. It can also show when different species split from one another. Combined with the fossil record, the technology is helping to provide a far more detailed view of how life on the Earth is related and how it evolved. The timeline above shows from the perspective of humans how we diverged from other groups of organisms . The timeline on the left shows when man first diverged from their best friend, dogs, as pictured on the right . The traditional view of evolution has been as a tree that grows ever more complex branches over time . By searching in the database compiled by the researchers, which is available as a free iPhone app and online, it is possible to see when two species separated in evolutionary history. For example, homo sapiens and dogs split from a common ancestor 94.2 million years ago while cats and dogs separated sometime later at around 55.1 million years ago. Crows - a bird that has been shown to have intelligence equivalent to chimpanzees and even young children - separated from chimps and the rest of the primate family 296 million years ago. The research has also helped to show that one of the most popular theories of what drives evolution may not be completely accurate. Biologists have long believed that life on Earth has undergone explosions in diversification as life has spread out to fill environments and to take advantage of new food sources. Major extinction events, like the demise of the dinosaurs, are thought to have been crucial in allowing life to undergo rapid periods of change as new species appeared to fill the gaps left by those that had died out. However, the new research by Professor Hedges and geneticist Professor Sadhir Kumar at Temple University, showed that evolution has actually occurred at a relatively constant rate. Professor Hedges said: 'Taken together, this indicates that speciation and diversification are separate processes from adaptation, responding more to isolation and time. 'Adaptation is definitely occurring, so this does not disagree with Darwinism. 'But it goes against the popular idea that adaptation drives speciation, and against the related concept of punctuated equilibrium which associates adaptive change with speciation.' The darker the shade of grey on the new timeline the earlier a group of speices is thought to have occurred . Humans sit within a relatively small section marked by primates in the above view of the new timeline .
Biologists at Temple University  created a spiral shaped view of evolution . They used data from 'molecular clock' studies on more than 50,000 species . These analyse mutations in DNA  to calculate when species evolved apart . It shows dogs and humans shared a common ancestor 94.2m years ago . Crows and chimps separated from each other more than 290m years ago . The study shows the diversity of life on Earth has grown at a constant rate . This contradicts the traditional view of evolution as occurring in bursts .