Both biome and ecoregion are ecological terms. Biome refers to a major regional group of plant and animal communities adapted to the natural environment. Biome can be of two types: terrestrial(land) and aquatic(water). Ecoregion, which is an abbreviated form of ''ecological region', refers to a smaller class. Each biome consists of several ecoregions, an ecoregion(also called bioregion) covering a realm of land/water having geographically distinctive communities, sharing the same envoronmental conditions and ecological dynamics.
Yes, an ecoregion does consist of different ecologically distinctive communities and species.