This is Lithopodius Nullar, a simple creature with a tendency like any other species to reproduce offspring. Lots of offspring. Although the offspring inherit many characteristics of their parents, no two individuals in the population are exactly the same. This variation is vital to the survival of the species as only a fraction of Lithopodius will actually survive, long enough to reproduce themselves. As a result, only those with characteristics that are best suited for survival in the environment will pass on these successful traits for the next generation. Those with characteristics less suited to the environment are less likely to survive and reproduce. This process is called natural selection and over time and generations it leads to the build up of favorable characteristics in the population of the species. The result is a transformation of a population over time to suit its environment. This is known as adaptation. Environmental pressures can also change. But as long as variation in a population exists, new adaptations can occur, ensuring the survival of the species.