Was Darwin Wrong ? An Alternative Theory Emerges

Until now, Charles Darwin's concept of survival of the fittest and natural selection has been considered  the key to the evolution of all living things.
But a new study by researchers at the University of Bristol England and published in Biology Letters suggests "living space," not competition between species , is responsible  for evolutionary patterns throughout history.
Using fossils to focus on land animals , the research team suggests that  animals have survived more easily in favorable environments that offered more food and less chance of being hunted and eaten by other animals.
At Yale University in Connecticut , evolutionary  biologist Stephen Stearns isn't convinced by the study findings.
"they have an interesting pattern , but I think they misinterpreted it.  basically, what they show is that a lot of evolution is driven by organisms  moving into new roles or  onto land or  into new areas , and they argue  that's evidence that competition is not so important," Stearns said.
Stearns, the author of "The Evolution of Life Histories"  ( Oxford, 1992 ) says it doesn't make  sense for animals to just pack up and move from one environment to another . "Why would they move if everything  was comfortable where they were ? So, competition probably is one of the things that drove them into the new environment," he said. 
"It's a trade-off: Should I stay here and deal with what I've got  here, or should I go somewhere else  ? Well, going somewhere else  is always a  challenge,  because  wherever you have been, you're always pretty well adapted to that , and for the only reason to go somewhere else is if the conditions here are deteriorating."
One of the authors of the British study, Mike Benton, told the BBC that "competition  did not play a big role in the overall pattern of evolution."
"Even though mammals lived beside dinosaurs for 60 million years, they were not able to out-compete the dominant reptules. But when the dinosaurs went extinct, mammals quickly filled the empty niches they left and today, mammals dominate the land." But Stearns says the pattern the British researches have documented isn't sufficient evidence  to determine what actually caused  the pattern.
Overtime , he said , "conditions are probably going to  be deteriorating because other organisms are evolving to be better  at extracting resources from your environment than you are , or they're evolving to be better at eating you. "I think they overinterpreted their results when they claimed that they can conclude  that competition wasn't driving it. 
Stearns explains the concept of "living space" doesn't only relate to a location or a physical place where animals live.
When you're talking about 'living space,' it's not really geography - it's like, what role do you play in the community ? You can't really have squirrels until you have trees. That's what they mean by 'living space.' While Stearns and the British researchers  don't see eye to eye, he welcomes the study because it fuels scientific debate. And because evolution is an ongoing , long process, he believes the study will add to scientific knowledge.
It will have a standard academic impact, and there  will be some critical commentary and other people  will see if they can actually replicate the results - scientists  don't usually believe a result until it's been independently replicated, and that hasn't happen yet.
Just a thought : "After it has been criticized and sifted and we know what parts of it stand up , it might become the textbook for evolution . But surely Darwin can't be all wrong.
 Why can't the two theories co-exist? Why can't evolution be a cocktail of cicrcumstances like everything else on earth? Some from column A and some from column B.