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In the present chapter we present the results of evolutionary studies ofexoplanetary atmospheres. We mostly focus on the sub- to super-Earth domain,although these methods are applicable to all types of exoplanets. We considerboth thermal and nonthermal loss processes. The type of thermal loss mechanismdepends on so-called escape parameter $\beta$, which is the ratio of thegravitational energy of a particle to its thermal energy. While $\beta$ isdecreasing, an exoplanet switches from classical Jeans to modified Jeans andfinally to blow-off escape mechanisms. During blow-off the majority of theatmospheric particles dispose of enough energy to escape the planet's gravityfield. This leads to extreme gas losses.  Although nonthermal losses never exceed blow-off escape, they are ofsignificant importance for planets with relatively weak Jeans-type escape. Fromthe diversity of nonthermal escape mechanisms, in the present chapter we focuson ion pickup and discuss the importance of other loss mechanisms. The generalconclusion of the chapter is, that escape processes strongly shape theevolution of the exoplanets and determine, if the planet loses its atmospheredue to erosion processes or, on the contrary, stays as mini-Neptune type body,which can probably not be considered as a potential habitat as we know it.

Stellar Driven Evolution of Hydrogen-Dominated Atmospheres from Earth-Like to Super-Earth-Type Exoplanets