You've already studied evolution--and learned about the enormous competitive pressures from the millions of species in the rainforests of the world. You've also studied the rapid rate of reproduction (and hence mutation and variation) that makes evolution possible there. Phytochemicals from plants provide powerful discouragement to would-be herbivores, so rainforest plants are the most metabolically innovative on Earth. Without them, the leaves of rainforest plants would have no resistance to insects, molds and bacterial infestations. A single plant might contain as many as 50 variations of the chemical group known as alkaloids (like caffeine, nicotine, opium, or cocaine.) Those are just some of the reasons why the rainforests are treasure troves of medicines, both discovered and undiscovered. While 25% of Western pharmaceuticals are derived from rainforest ingredients (121 prescription drugs), less that 1% of the tropical trees and plants have been ever been tested by scientists. Consider a few of these medicines that we know already:
Coca leaf (in tea) has been a medicine for headaches for a century or more. It is familiar to the indigenous people of Peru.
Muņio is a mint-like plant that is also commonly used for headaches.
Morphine is a derivative of cocaine.
Quinine is derived from the cinchona tree, and still used as an anti-malarial drug.
Vincristine (from periwinkle) is a powerful anti-cancer drug
Uņa de Gato--an herb often considered a powerful anticancer drug. (http://nccam.nih.gov/health/catclaw/)
You may also have heard of some rainforest drugs known for their psycho-active effects, such as ayahuasca. This hallucinogenic (made from the vine of the ayahuasca plant and other plants) was known to the earliest missionaries, and is still occasionally used in religious services.
Where will the rest be when we are ready to research them? Experts estimate that 137 plant, animal and insect species disappear every single day due to rainforest deforestation--50,000 species a year. This is not only because of logging and deforestation, but because of climate change (global warming) which is reducing the water that comes from the Andean icepack, expanding the range of many insects and other herbivores, and changing migratory patterns.
Ethnobotanists are frantically trying to learn from the traditional experts--often shaman--to preserve both the lore and the wisdom of those who have gone before them in the rainforest.
Preservation through Commerce
There are many groups, like www.rain-tree.com, who are specializing in the commercialization of natural rainforest products that can be harvested from mixed (old growth) forests. You already know that there is very little profit in clearing the land and raising cattle--perhaps $60/acre for grazing or $400/acre for lumber harvest. But a conservative estimate indicates that the careful harvest of rainforest fruits and medicinal plants might yield the landowner as much as $2400 per acre. (Remember, many of the most valuable rainforest trees may have been deliberately propagated by ancestors of today's residents for just that purpose.)
It's also necessary to help local rainforest residents resist change. Many traditional construction skills are actually more effective in the rainforest than more "modern" materials like metal or tile roofs. But the labor required to make a single palm piece like the one at the right (about 3 m/10 feet in length) doesn't currently justify the value--about 50 cents! If logging or mining companies offer higher salaries, the traditional skills will disappear.
To significantly affect the way in which people make their livings, there must be both demand and the facilities to warehouse and transport products to market. There must also be more awareness on the part of consumers. When people not only donate to organizations like the Nature Conservancy, but specifically ask for rainforest-friendly products, there will be more pressure to preserve than to destroy.
When you are at ExplorNapo, be sure to visit the ReNuPeRu Ethnobotanical Medicinal Plant Garden, located between the ExplorNapo and Sucusari reserves.