The Southern continents, particularly Africa and Australia, don't get very far from the Equator. This makes them much hotter in general than the Northern continents, and they don't have the same extremes. Locations at the southern extremes of Africa and Australia are the same distance from the Equator as places in the very southern parts of Asia, Europe, and North America, but those continents spread much further from the Equator, giving them a much greater range of climates and ecosystems.