Scientists believe that evolution is driven by random mutations combined with natural selection.
Thus, they believe that random mutations caused some animals to develop protrusions that happened to be shaped like wings and by pure coincidence allowed those animals to fly. Those animals then had an advantage over others which caused them to survive while animals with non-useful protrusions became extinct.
I think this is a load of excrement, but I can't prove it and it frustrates me tremendously that no-one has yet been able to successfully disprove the random mutations hypothesis.
I believe that there are beings (spirits) responsible for designing the bodies of plants and animals. There is probably one such being per species which would explain the fact that different species compete with one another and develop defensive body functionality against their predators' offensives and new offensive body functionality against their prey's defences.
For example, there is probably one being who has the interests of bats in mind and tries to constantly improve the bodies of bats to enable them to better catch moths and at the same time there is probably another being who has the interests of moths in mind and tries to constantly improve the bodies of moths to prevent them from being caught by bats.
Did Steiner somewhere describe the existence and work of such beings or give an alternative explanation about the mechanics of evolution?