Effects of physical changes in the environment - examples: - A change in the Australian climate from cool and wet to hot and dry, affecting the change in vegetation from rainforest to woodland, this led to changes in animal life. - The drying up of lakes in the Australian interior, leading to the evolution of plants and animals that could conserve water - A study of snow gums in and around the Snowy mountains have shown a gradual change in the characteristics of the trees compared with those growing in warmer conditions - decrease in height of the tree and leaf length as altitude increases.