It all began with a branch: there were no leaves involved, not even a twig, but branches can be difficult to organise. It was the storm of the century, or was it the month, perhaps of the world. Whilst the news stations were discussing its proportions, the branches were falling. It was when that particular branch fell, blocking the entrance to Mrs. Smith’s house it began to get critical.
She called the local authorities, but suddenly the call cut off. The wires had been destroyed by a falling branch. In the meanwhile the dogs were having the time of their lives. At last there were enough branches for every dog. Each dog had its own branch in its jaws. The fire brigade was called to the rescue, but they could not help. Branches had fallen onto the trucks and their radio was not functioning, because the power lines were down due to the damage caused by the branches.
Mrs. Smith was now desperate, her dog was now collecting more branches and leaving them outside the house. After a week of falling branches the village was no longer a village because you could only see branches. This was happening all over the world. Many thousands of years later civilisation had disappeared as we knew it. Everyone lived in caves until one day two branches fell and ignited a spark. Fire was discovered and the whole civilisation thing started up again.
You think this is silly, so do I, but who knows, it could have happened this way. In the meanwhile the dogs were living in nicely constructed kennels. That is called evolution.