Hello. The programme you're about to listen to was first broadcast（广播） on the BBC Learning English website in January 2010. For more English language learning programmes and podcasts, search for BBC Learning English. The term 'biodiversity（生物多样性）' is a shortening of the expression 'biological（生物的） diversity（差异）'. It refers to the variety of all life forms on our planet, from trees to rice and roses（玫瑰）, from elephants to tiny（微小的） organisms（生物体） like bacteria（细菌）. It also covers rainforests（（热带）雨林）, oceans and deserts, various（各种各样的） environments or ecosystems where forms of life depend on each other.