rain is very important for life in certain areas, this is why you see little life in deserts and even they need rain occasionally. more rain will lead to more life, first, it will be the plants that move in, then once they grow, vegetation eaters will move in, then after that meat-eaters will move in to eat those creatures and the ecosystem will flourish.
Birds and bats have homologous limbs because they are both ultimately derived from terrestrial tetrapods, but their flight mechanisms are only analogous, so their wings are examples of functional convergence.
