EXPLORING BIODIVERSITY: A Guide for Educators Around the World

q
Vanishing Along with their Habitats
While we have a pretty good idea about how
many mammals, birds, and other vertebrates are
threatened or have already become extinct, we
have no idea how many species of invertebrates
and microorganisms have been or are being lost.
What we do know, mainly through recent studies
in the tropics, is that vast numbers of unidentified
species of invertebrates and microorganisms are
adapted to and therefore dependent on localised
habitats. Since these habitats are being wiped out
by logging, farming, mining, and other human
activities, many scientists believe that scores of
species, unknown to science, are being extinguished
in the process.
A Growing Concern
In 2002, the number of people on Earth is
estimated at over six billion—more than twice as
many as in 1960. About 77 million more people
are added to the planet each year. This annual
addition, equivalent to almost twice the population
of Colombia, amounts to over 210,000
births every day. Most experts think that human
population is likely to reach between 8 and 11
billion by 2050
WORLD POPULATION GROWTH
There is little doubt that our growing population
will result in continuing habitat loss and will put
enormous pressure on Earth’s natural resources.
Non-renewable resources, such as fossil fuels
and certain minerals, could someday become
depleted. While some people argue that new
technologies could indefinitely extend the use of
non-renewable resources and allow the use of
alternative ones, many others feel that technology
can only delay the time when the Earth loses its
ability to sustain us.
Renewable resources, such as trees, won’t
necessarily run out, but unmanaged use of them
can lead to other problems. For example,
increasing demands for paper and other wood
products could lead to increased plantings of
monocultures—stands of a single species of tree.
Planting monocultures is an efficient way to
ensure a steady supply of wood for wood
products, and it may allow large areas of high
biodiversity, such as tropical rain forests, to be
spared. But monocultures can be less resistant to
disease than more diverse forests, which often
means that they need to be sprayed with more
pesticides. They also may require high levels of
40