Conservation of biodiversity

Now that we can name living things and measure the biodiversity of a place, this lesson asks the biggest question of all: how do we protect that variety of life? We start with the reasons biodiversity is worth maintaining - ecological, economic, medical, genetic and ethical. We then look hard at keeping water clean, building up the two mechanisms the syllabus demands: bioaccumulation, where a toxin concentrates as it climbs a food chain, and eutrophication, where added nutrients trigger algal blooms that strip the water of oxygen. We outline how endangered species are conserved in-situ, inside national parks and marine parks, and ex-situ, in zoos, botanic gardens, seed banks and 'frozen zoos'. We see why populations sometimes need limiting by culling or contraception, why invasive alien species must be controlled, and how degraded habitats can be restored. Finally, using Namibia, South Africa and Botswana, we investigate how rhino and elephant poaching strikes directly at the tourism economies of the whole region.