In the desert biome the temperature's are extreme, they could get to over 100 degrees. Plants and animals adapted to their environment over many centuries. The amount of precipitation a plant or animal get can effect how they grow, plants need lots of water so the can grow and flourish.
Based on the temp and precipitation, different types of plants and animals can survive in those environments. A cactus would thrive in the desert because they hold water very well and don't need it often, and they don't mind the heat. An orchid would thrive in a rainforest because the precipitation would water the plant and the environment would feed it. In a grassland biome, there must be a moderate amount of rain to support the plant life and animals. The vegetation would be enough to support a multitude of herbivores that would be perfect for the grassland predators like coyotes and wolves.
The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3.5 billion years old. This may be somewhat surprising, since the oldest rocks are only a little older: 3.8 billion years old!
The Great Barrier Reef makes up about 10 per cent of the world's coral reef ... vast expanse are a unique range of ecological communities, habitats and species – all ... includes some 3000 coral reefs, 600 continental islands, 300 coral cays and ... to just north of Bundaberg; is between 60 and 250 kilometres in width