How are scientists able to estimate the numbers of animals going extinct?
There is a direct relationship between the size of an area and the number of species that it contains. A square yard of temperate forest habitat may have 10 species of plants, while an acre will often have hundreds. The larger the area, the more species encountered-up to a point. Of equal importance is the range of each species. Species that are restricted to small geographic areas are much more likely to go extinct than are those with widespread distributions. Also, the smaller the population, the higher the probability of extinction. And therein lies a disturbing fact. It is thought that tropical species commonly have smaller populations and much more restricted distributions. Thus, destroying an acre of tropical forest will likely have a much higher extinction impact than the loss of an acre of temperate forest. Dr. Edward O. Wilson of Harvard University estimates that if 1% of the world’s tropical rain forests are destroyed each year—a conservative estimate based on current rates o
