Tree frogs come in two colors, Gray and Green. They are found in a wide variety of habitats that surround most inland waters. For instance, one of them is swamps. They eat insects.
In swamp and marsh habitats, green frogs are able to camouflage from predators while gray frogs are exposed to their hungry predators, snakes and birds. So the predators eat the gray frogs which allows the green frogs to reproduce and the population of the grey frogs wiped out. There are going to be plenty of green frogs able to camouflage.
After a long period of time a flood occurred and almost half of the green frog population died. The reason why that 50% died was because they did not not know how to swim while the other half knew how to swim. The reason why the one half did know how to swim was because they had such as a small waist, no neck and a broad, flat skull make his body streamlined for swimming while the other half didn't.
One day while they were eating insects. The insects decided to fly all the way up to the top of the tree. So the green frogs jumped and climbed up the tree all the way to the top. They started stretching their tongue and they all ate successfully except for the 25% short tongued, green frogs. Those short tongued frogs kept on trying and trying to reach the insects but they just couldn't.
So after some time that 25% starved to death. Now that all the short tongued frogs died, all the long tongued frogs reproduced many offspring and those offspring were green and camouflaging in plants, could swim, and had long tongues to reach faraway insects to eat them.