  We compare the speed with which a sexual, respectively an asexual, population
is able to respond to a biased selective pressure. Our model focuses on the
Weismann hypothesis that the extra variation caused by crossing-over and
recombination during sexual reproduction allows a sexual population to adapt
faster. We find, however, that the extra variation amongst the progeny produced
during sexual reproduction for most model parameters is unable to overcome the
effect that parents with a high individual fitness in general must mate with
individuals of lower individual fitness resulting in a moderate reproductive
fitness for the pair.
