A biome is a specific area on Earth that is defined by its climate, animals life, plant life, and even the amount of salt in water. Biomes are split into two categories: terrestrial and aquatic biomes. Terrestrial biomes are biomes on land while aquatic biomes are biomes in water. The main types of terrestrial biomes are tropical rainforest, desert, tundra, savanna, temperate deciduous forest, and taiga. The main types of aquatic biomes are freshwater, estuary, and marine. Each of these biomes are unique and vary by temperature, rainfall, salinity (salt in water), plant life, and animal life. These characteristics make these biomes unique.