Lizards thrived, having more than enough insects to eat. The population was steady and there was more than enough food and water to go around.
One summer, the sea level started to rise, and caused lots of flooding. Large sections of land were submerged under water and lots of mud started to appear. The insects that the lizards relied on started diapering underground.
Due to the muddy landscape, the insects started living underground and in the mud. Many lizards could not reach the lizards due to how deep the critters had gone.
The lizard population started decreasing, but of the lizards that survived, lizards with longer tongues started appearing. These lizards were able to reach the critter in the ground because their tongue's were long enough.
As the lizard population started increasing again, the lizards with longer tongues became dominant compared to the shorter tongues and almost all the lizards had long tongues.
With the ability to reach the food that they needed to survive, the lizard population started growing and reproducing again.