Biodiversity | Global Issues Tours

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What is biodiversity?
Who is involved?
Where is biodiversity the greatest?
Why is biodiversity important?
Why does the depletion of biodiversity continue?
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What is biodiversity, anyway?

How many different kinds of animals, plants, people, and organisms are on the Earth? Scientists have not yet definitively answered this question, but they have catalogued 2 million species and estimate there are around 13.6 million species in existence.¹ In fact, there are over 8,800 species of ants alone!²

Biodiversity describes the variability among living organisms from all sources including land and water ecosystems; this includes diversity within species, between species, and of ecosystems.^³ We lose some of our planet’s biodiversity every day. At least 16,928 species are threatened with extinction: 21% of mammals, 12% of birds, 31% of reptiles, 30% of amphibians and 37% of fish globally are threatened.⁴

Check out the Hotspots Explorer Interactive Map to explore biodiversity hotspots from around the world.

Who is involved?

Human activities are responsible for the vast majority of biodiversity loss. By changing our land use, introducing foreign species to different ecosystems, overexploiting resources, and polluting the environment, we have caused a great deal of damage. One example of changing land use is the depletion of the forests—40.4 million acres of the world’s forest land were cut down between 1990 and 2005.^⁵ To put this in perspective, the entire state of Missouri is about 45 million acres.

Jungle burned down in Mexico for agriculture.

Where is biodiversity the greatest?

70% of the world's species are found in just 12 countries: Australia, Brazil, China, Colombia, Costa Rica, Ecuador, India, Indonesia, Madagascar, Mexico, Peru and Democratic Republic of Congo.^⁶ 50% of the world’s endemic plant life alone is packed into just 34 hotspots covering 2.3% of the Earth’s surface.^⁷

Why is biodiversity important?

Much of our food and medicine derives from the biodiversity of plants and animals.

Food: Genetic diversity in crops makes them adaptable to changes in their environment, like new pests, diseases, and climate conditions.^⁸ There are only around 30 crop species dominating modern agriculture worldwide. Countries are now recognizing that declining biodiversity can have catastrophic consequences, like mass famine. An example is the cassava blight in East Africa caused by a virus called “brown streak”, which attacks the tubers and makes them inedible. There are no cassava species remaining today that are resistant to the virus.^⁹ 800 million people around the world depend on cassava as their staple food, so blight will eventually lead to famine, unless a replacement species is found or created.^¹⁰

Many countries have signed treaties that protect at least some of the biodiversity of these species in germplasm banks, but these programs do not include all species. There are 7,000 species used on a more limited basis that could one day become extinct.^¹¹

Medicine: Plants are a critical part of the creation of many medicines that most of us take for granted.A study of the 25 best-selling pharmaceutical drugs in 1997 found that 11 of them (42%) were biologicals, natural products or entities derived from natural products, with a total value of US$ 17.5 billion.^¹² A wealth of biological diversity fuels the discovery of new medicines to battle serious illnesses like cancer. One example of this is the drug Taxol, one of the best selling cancer drugs in U.S. history, which was derived from the Pacific yew tree.^¹³

Usually only one in 40,000 natural products yields an effective medicine, but each medicine can save millions of lives so the incentive for scientists to preserve biodiversity is large.¹⁴

A Pacific Yew tree.

Why does the depletion of biodiversity continue?

The primary cause of biodiversity loss is increasing human population and its corresponding increase in demand for food, medicine, and fuel. Products made from biodiverse environments are stronger and more adaptable than their single-species counterparts, driving corporations and individuals to overharvest these valuable resources. Overharvesting is a proximate cause of biodiversity loss, along with climate change and pollution. Root causes for biodiversity loss include government policies, poverty, social change, and demographic shifts.¹⁵