Maintaining biodiversity comes with a few practical benefits. When a species exhibits great genetic diversity, it has a larger pool of genes available to it. Having more genes makes the species better equipped to respond to changing conditions.
Take cheetahs, for instance. About 10,000 years ago, all but one species of cheetah became extinct, leaving just Acinonyx jubatus in Africa. This population of animals was relatively small, which forced closely related individuals to mate with each other. Over the years, inbreeding eliminated all of the genetic diversity from wild cheetahs, leaving them vulnerable to sudden changes in their environment, such as the introduction of a new virus.
Humans, too, benefit from genetic diversity, but we also rely heavily on the great variety of organisms that share the planet with us. Plants, animals, bacteria and fungi provide raw materials for human use. We base our diets on food crops and the animals that eat them. We clothe ourselves using material derived from plant and animal fibers. We take advantage of single-celled organisms, from bacteria to yeast, to drive important industrial and manufacturing processes.
And then there's medicine. Almost 40 percent of all prescription drugs sold worldwide contain natural compounds found in different plant, animal and fungal species [source: USAID]. Penicillin stands as a classic example of how mankind has benefitted from a drug obtained from another organism.
Perhaps the biggest benefit of biodiversity isn't what compounds an individual species carries in its cells, but how that species fits together and interacts with other species in its ecosystem and how that ecosystem works with others across the world.
Take pollination as an example. Plants rely on pollinators -- birds, mammals and insects -- to help transfer pollen and, ultimately, to create seeds and fruit. Honeybees are an important pollinator, particularly for specialty food crops. Unfortunately, in 2006, some beekeepers began reporting losses of up to 90 percent of their hives [source: Kaplan]. Scientists now refer to this as colony collapse disorder, and they worry that crop production in the United States could suffer significantly.
Pollination is just one service provided by the complex interplay of living things. Ecosystem services also purify water, generate fertile soil, break down wastes, help control pests and moderate weather extremes. Human activity has taken a toll on all of these processes and will continue to do so as the global population swells from 6 billion to 9 billion people by 2050 [source: Secretariat of the Convention on Biological Diversity]. It's a sobering thought, even to those of us learning about biodiversity in our suburban backyards.