We can stop expect for the miss link in the dinosaur - shuttlecock changeover now because it was seamless . razz are a continuum of millions of years of evolution , and there was no great leap between non - birds to birds .
research worker assembling the most comprehensive family tree of two - legged , meat - eating dinosaur to date expose that familiar bird feature – like feathers , wings , wishing bone , hollow os , and bills – evolved over millions and millions of years , lento accumulating small shift in shape and routine . But once these pieces were in place , an evolutionary explosion commence . The gradual assembly of the doll organic structure plan as we now lie with it , culminated in rapid rates of evolution . Theworkwas published inCurrent Biologythis hebdomad .
“ There was no moment in time when a dinosaur became a fowl , and there is no single missing link between them , ” saysUniversity of Edinburgh ’s Steve Brusattein auniversity assertion . “ What we think of as the classic bird skeleton was pieced together gradually over decade of millions of long time . Once it came together amply , it unlock great evolutionary voltage that allowed birds to germinate at a top-notch - charge rate . ”
To examine the evolutionary link , tempo , and pace of the dinosaur - bird conversion , Brusatte and colleagues analyzed the anatomical make - up of 853 feature article ( order from air travel sacs to wristbones , or miss thence ) in 152 extinct birds and their close non - avian dinosaur relative . Then they used statistical methods to gather a family tree called a phylogeny ( pictured below ) .
The squad found that the emersion of birds 150 million years ago was a gradual process that commence pretty much when dinosaurs appeared on Earth around 230 million years ago . With some dinosaur becoming evermore “ birdy ” over time , it ’s very difficult to tie a dividing line between them . “ This process was so gradual that if you traveled back in time to the Jurassic , you ’d find that the early bird reckon indistinguishable from many other dinosaurs , ” study coauthorSteve Wang of Swarthmoresays in anews acquittance . When all these pieces make the archetypal bird skeleton were in place , “ birds then evolve apace , eventually leading to the great diversity of specie we hump today . ”
The far-famed early bird , 150 - million - class - oldArchaeopteryx , was thought to interpret a great evolutionary leap from dinosaurs , National Geographic explains , but these findings show that its avian trait evolve in dinosaur forebear long before . This 80 - million - year transition was capped by unusually elevated bursts of evolution .
“ It is peculiarly cool that it is evidence from the dodo record that shows how an oddball outgrowth of the dinosaurs paved the way for the spectacular variety of bird species we see today,”saysstudy coauthorGraeme Lloyd from Oxford . Here ’s a simplified variant of their phyletic relationships :
Images : Jason Brougham ( top ) , Steve Brusatte ( bottom )
