Evolutionary progress has long been associated with the extinction of species. So why should we be concerned now, even when the number of species at risk is substantial, such as one tenth of the Australian flora? The reasons for concern are many stranded. Compassion is one strand. Remember the instructions to Noah: 'And you shall bring living creatures of every kind into the ark and keep them alive with you'. Guilt may be another strand, that our hunting, clearing, collecting, pollution, introduction of competitors and other human activities may have endangered species such as the Orange-bellied Parrot. Nostalgia for what was and concern for what might be also play a part; species at risk include some which are of immediate use, such as the whales, and many of potential use, whether drug plants in the forests of the Amazon or a wild relative of the soybean in Victoria. Aesthetic considerations are also involved, particularly where colourful birds or unusual flowers are threatened. We cherish diversity, as culturally desirable, and are delighted when supposedly extinct species such as the notornis and coelacanth - and maybe yet the thylacine - are rediscovered. The Loch Ness monster has already been blessed with a Latin binomial in anticipation! Diversity is also of ecological as well as of cultural value, contributing to the stability of ecosystems, as in the case of insects and birds which fertilize the flowers and disperse the seeds of plants.