Conservation biology aims to protect biodiversity by studying species and ecosystems. There are two main conservation methods - in situ conservation preserves species in their natural habitats such as protected areas, while ex situ conservation preserves species outside their habitats in facilities like zoos, seed banks, and botanic gardens. Protected areas cover about 5% of the world's land and play a key role in maintaining representative ecosystems, but traditionally excluded local people which could harm biodiversity. Conservation now takes a more holistic approach involving local communities.