The Way of Science

Biodiversity

For many decades, there has been a consistent prediction of environmental disaster coming from the biological community. For at least 25 years, many biologists have tried to convince the public that humans are degrading all aspects of our environment to the point where significant, highly undesirable, and irreversible changes will descend on us. Since the eighties, the "environmental movement" has been getting more attention than earlier, but is that attention merely superficial? What is the evidence that the scientific doom-sayers are presenting, and is it being accepted by the public? (Remember Asimov's corollary?)

For years, concerned biologists have tried to convince the public that air and water quality are disintegrating; that our fisheries, our soils, our resources in general are being eliminated; that we may irreversibly change world climate; that we are eliminating habitats at such a rate that species extinctions are going to exceed anything in the history of life (17 species an hour may be going extinct right now); that our world is grossly overpopulated by humans. (Lest you think that the US is not part of the overpopulation problem, consider our rate of resource use: the US has one-twentieth of the people, but uses one-third of the world's oil. Our consumption/pollution rates for other factors are similar.)

We cannot possibly consider the evidence for all of these possible disasters. The best we can do, in limited time, is to select one "doom prediction" and examine it in outline. We have chosen the problem of loss of biodiversity. Although many other topics could have been chosen, we picked this one because biologists like us (M. Wirth and D. Dunlop) consider this problem to be the most serious one facing humans.

Here are your sources for classroom discussion:

1. Film: Life in the Balance (see schedule.)
2. (#16) Diamond, J. 1990. Playing Dice with Megadeath. Discover 11(4): 54-59.
3. (#17) Myers, N. 1988. Tropical-Forest species: going, going, going, ... Scientific American 259(6) : 132.

As you watch the film, and as you read, consider the following questions:

1. How many species, world-wide, are presently known?
   
   
2. How many more might exist, and how can we estimate this number? Watch carefully the section on Terry Erwin's work on estimating total biodiversity.
   
   
3. Why do extinctions occur? Is extinction a normal part of Evolution? If so, why are so many biologists worried? In other words, pay attention to rates.
   
   
4. Why should we preserve biodiversity? Consider this question in three ways:
   1. What's in it for us humans? What will you humans lose if biodiversity is severely reduced? What's the price of losing species?
      
      
   2. Are there ethical aspects involved? E.O. Wilson, a major figure of 20th-century biology, has said, " if a price can be put on something, that something can be devalued, sold, and discarded."
      
      
   3. What happens to the path of Evolution after mass extinctions? Consider this question for both short-term and long-term effects. Remember the dinosaurs?