What are the broad adaptation that creatures and plants have made for survival in the desert biomes and tundra?

For plants, the aerioles and spines help reduce water loss. the spines also help protect the plant. this is seen in the opuntia or the mammillaria. the rosette form of the aloe and agave help the plant to get as much water as it can. the waxy surface of the aloe and agave help it to prevent water loss as well. Euphorbes have latex which is poisonous. white hairy surfaces on certain plants help it to reflect the hot sun