Sunday, January 11, 2009

Extinction

I've thought a lot about the current rate of extinction within the world. It is currently estimated that "on average, a distinct species of plant or animal becomes extinct every 20 minutes". That's an unbelievably large number. While not all of those extinctions are human caused, the vast majority are. Additionally, 70% of biologists view the present era as part of a mass extinction event, possibly one of the fastest ever. Yet, there is no outrage over this. Its not on the news, it's not the topic of day to day conversation, it rarely surfaces as a side conversation and is then ignored. There are a couple of possible explanations for this. It could be that the vastness of the problem is simply overwhelming, or it could be that people don't really understand the numbers, or it could be that they have no idea on what to do about it, or it could be that they just don't care.

When I think of extinctions I choose to consider specific cases and not the overall number. This allows me to personalize the impact and contemplate what it means for each individual species. There are a couple of specific species which have gripped my mind. The significance of these species is that their story has been told, not just the number. I will relate two such stories here.

I first read about the golden toad in E.O. Wilson's The Future of Life. This is an excellent book for biologists and non-biologists alike. E.O. Wilson is a legendary biologist with a great deal of experience. He tells the story of many species, but one was highlighted, El Sapo Dorado, the golden toad. This golden toad was first discovered near Monteverde in Costa Rica in 1966. This is the only known location of this species. For 20 years there were estimated to be about 1500 toads each year. In 1987 there were over 1500, in 1988 there were 11, in 1989 there was 1. Since May 15, 1989, none have been seen despite very intensive searches. The specific cause of this extinction is not known, but most hypothesis point back to man. Picture that last male toad singing with all its energy trying to attract a mate. Likely unaware that he was the last of the species. That he would never have a chance to mate. That when he died that particular line of evolution's creation would exist no more. And we were the likely cause.

The next story I have heard a few times as well. It was featured on both Birdnote and Science Friday during the last month. The species in a bird known as the Kauai O'o. This bird is endemic to the the Hawaii island of Kauai. Follow the link to listen to its song. The recording is of the last male of the species, singing for a mate. It's a beautiful song that becomes more impactful when you understand the song's dynamics. The song was sung as a duet between the male and female birds. Each gap in the song was to be filled in with the female's counterpoint. When listening with this knowledge, its is incredibly sad. This lone bird sang for two years to find a mate. No other birds existed to fill in the duet. He sang and sang and sang, but no one came. Then he died. Once again, the ecological niche which this species filled is now empty, and we are no better for it.

This is what extinction means to me. It not that an estimated 72 species go extinct every day, or that we are in the next mass extinction event of our own making, its that each and every one of these species has a tale to tell. If we would only listen.



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