c=2;l=10;
modell={u'[z]==v[z], v'[z]== - c v[z] - u[z] (1 - u[z]),
u[0]==u0, v[0]==v0};
p:=Module[{},loesung=NDSolve[modell,{u,v},{z,0,l}]; 
abb=ParametricPlot[Evaluate[{u[z],v[z]}/.loesung],{z,0,l},
DisplayFunction->Identity,
PlotPoints->50]
];
bild1a=Table[{u0=0.7; v0=0.5- 0.1 i;p},{i,0,15}];
bild1b=Table[{u0=0.05 i; v0=-1;p},{i,1,13}];
abb0=Show[Evaluate[bild1a,bild1b],
DisplayFunction->$DisplayFunction,
PlotRange->All,ImageSize->{400,300},
AxesLabel->{"u","v=u'"}];