Publication of Archival Library and Museum Materials
Publication of Archival Library and Museum Materials
Publication of Archival Library and Museum Materials
Linking Florida's Natural Heritage

Curriculum Materials

The Biodersity Dilemma: What is Biodiversity?

Overview

The word biodiversity is short for biological diversity, it describes the number of different kinds of plants and animals in a specific area.

Levels of Biodiversity

This diversity can exist at three different levels. All are very important and related to each other:

Genetic level:

This includes the variety of genetic information within a species or population. The more diverse its genetic code, the more likely a species will survive changes in the environment. For example, we have different types of apples. Some kinds are more resistant to disease than others, while others may tolerate warmer climates.

Two examples of how important genetic diversity is are as follows: The loss of Potato blight wiped out the potato crop in Ireland in 1845 and 1846 causing starvation and immigration of two million people. It took 80 years to find a resistant potato in Mexico and breed that resistance into US and European potatoes. When southern corn blight hit the U.S. in 1970, it reduced corn production 15%, and took three years to breed a resistant variety from the strains already on hand in the seed banks.

Species level:

This level includes a variety of different species within an ecosystem habitat that enables the system to remain stable even with changes or disturbances. For example, the salt marsh is full of a variety of different species including fish, crabs, herons, gulls, etc. that help enrich the system.

Most efforts to restore endangered species populations are targeted at this level. The Florida panther, manatee, red-cockaded woodpecker, and Florida scrub jay are all species that represent important biodiversity in Florida. Often, by protecting their habitats, we also protect an ecosystem.

Ecosystem level:

This level is the variety of different kinds of ecosystems within a region that enable the regions to cope with changes or disturbances. For example, migrating birds need two different kinds of ecosystems in two different parts of the world as well as in healthy ecosystem rest stops along their route.

As we lose many different types of ecosystems to development and consumption of natural resources, this level of global diversity decreases. For example, filling in mangrove swamps to build high-rise hotels on the coast or cutting down rain forests for grazing land and the sale of prized natural resources such as mahogany and rubber is dramatically decreasing the resiliency of ecosystem diversity.

Ecosystem, Species, and Genetic Resiliency

All three levels of diversity are essential to maintain life on earth as we know it today. Each level must be protected because they all depend on one another and must be resilient in order to survive. It is the variety of genes, species, or ecosystems that makes all three levels resilient.

The Importance of Biodiversity

Here is an analogy to help you understand what biodiversity does:

Let's pretend I'm giving you a free ticket for a flight to Hawaii. You'll take it, right? You might ask, "What's the catch?" Well, the catch is that the plane...is losing rivets...not too many....just a few every hour. You might want to know a few things about rivets and airplanes; like...how many rivets does a plane have? How many does a plane need to fly? Are some more critical than others? Can rivets function alone - or do they only work in sets?

That's a lot like our ecosystems and species diversity. We know plants and animals help our ecosystems provide ecological sservices - like the photosynthetic plants that give you food energy, and the decomposers that enrich your soil so trees are able to grow in order to provide shade you.

Suppose we asked these questions: "How many species do we have on this eco-ship?" "How many do we need?" "Are some more important than others?" "What is the minimum number we need to function?" We don't know the answers. Now think about it, wouldn't you like to keep as many of these rivets as possible?

How Biodiversity Benefits Humans

So, when we lose biodiversity, we lose access to many different plants and animals that we might need. Here are some specific ways that biodiversity helps us:

Scientists use the genetic diversity in our food crops so we can continue to grow plants that are resistant to pests and disease. Many of our prescription drugs were first made from plants and animals. If we continue to lose species, especially those not well researched such as those in tropical forests, will lose out on potentially valuable medicinal cures.


Ecosystems also help clean the air we breathe and the water we drink.

Without wetlands to purify water and forests to screen out pollutants from the air, we would need machines to provide this service.

Biodiversity stabilizes the ecosystem. It keeps our options open for the future. There may be resources out there that we don't yet understand their potentials, and we don't want to destroy them before we even know about them. Biodiversity also increases the beauty of the planet. What would Florida be without herons, eagles, or zebra long-wing butterflies?

Saving a Whole Ecosystem or Just One Animal in it?

So should we try to save whole ecosystems or just one animal at a time?
Trying to preserve either a single animal or even the ecosystem are both good ideas if in the long run they work to save the area. When you try to save an individual animal, especially a keystone species, you must provide it with a place to live and food to eat. What better place than its own habitat. Also, in the process of saving an ecosystem, you save all of the other plants and animals in that ecosystem by default. Sometimes it is easier to get people excited about saving an important animal like a parrot or a panda rather than an ecosystem. So we use some animals as ambassadors to get attention and operate in the limelight so we can protect the lesser known plants and animals in the ecosystem.

What is a Keystone Species?

A keystone species is one on which many other species in the ecosystem depend. For example, in a longleaf pine sandhill, if you were to take out the gopher tortoise, a keystone species, then the ecosystem would change dramatically. For example, the gopher tortoise digs burrows to live in and shares these homes with hundreds of other animals. Without a protective place to live, all of those other animals might die.


Image courstey of Ohio Historical Society

EXTINCTION

It is true that extinction is a natural process, but never before has it occurred at such a fast rate. And, depending on your view, it is not happening because of natural reasons now. Due to human actions and changes in our ecosystems, we have seen the extinction of thousands of species in just the last two hundred years; it is natural for only about one species to go extinct every hundred years.

Causes of Loss of Biodiversity

The easiest way to remember the five main causes of biodiversity loss is to think of the acronym HIPPO. It stands for:

 
Habitat loss

Some plants and animals require specific habitats and cannot live without them. Because of increasing development and other changes to the ecosystem, plants and animals are losing their needed habitats.

Invasive species

When an invasive species is introduced, into an ecosystem, it can change the entire makeup of that ecosystem. Over time, it may push out many of the native plants and animals. For example, melaleuca has replaced indigenous species in South Florida

Population Growth

The growth of the human population is increasing at an exponential rate, there are more and more people depleting resources and taking away natural habitats to provide for homes, farms, and roads.

Pollution

Humans continually contaminate the air, water, and soil with their everyday lifestyles. This makes it a bigger challenge for plants and animals to survive.

Over consumption of natural resources

Many scientists believe there are enough resources on the planet if humans only use what they need. However, when we have three TVs in one home, or enough clothes for a month, we are wasting valuable resources. The energy, and other raw materials used to make these products come from the environment. The use of these resources often brings disruption or pollution to the plants and animals. (The U.S, makes up 5% of the world population, yet we consume more than 50% of the earth's natural resources.)

Ways to Preserve Biodiversity

Here are just a few examples of ways people are already helping preserve biodiversity:

Here are some ways you and your friends and family can get involved:

Bibliography

Keystone species at Biodiversity Loss: Cascade Effect.

Extinction rates at Species: Unprecedented Extinction Rates and It's Increasing.