Biology 100/101
Lecture 22
Biodiversity II
(Print Version)

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Objectives

Why Preserve Biodiversity?

Pharmaceuticals

Foods

Biological Products

Ecosystem Benefits

Keystone Species

Studies of Biodiversity

Lecture Syllabus

IB 100/101 Home Page

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Text Readings
in Lewis, et. al.

Chapter 46, Environmental Challenges, pgs. 911-930.  The "Reviewing Concepts" boxes are valuable summaries of the main ideas in these sections of the text.

You have open access (no log-in or password needed) to instructional materials on the Text web site. Select the text chapter you want and use the links to the e-learning modules or other available materials. There is also a collection of study materials called the "Essential Study Partner" that you may find useful.

Objectives:

After studying this material you should be able to:

  1. Define the term biodiversity and explain how the three levels of biodiversity (genetic diversity, species diversity, and ecosystem diversity) are related and dependent on one another.

  2. Explain what is meant by "The Sixth Extinction" and why this should concern us.

  3. Explain how biodiversity is lost, how rapidly it is currently being lost, and some of the reasons why we might be concerned about this loss.

  4. Understand the problems associated with slowing the rate of loss of biodiversity.

  5. Explain the potential value of biodiversity in terms of both direct human uses and ecosystem level processes.

  6. Describe the relationship between biodiversity and keystone species.

  7. Explain some of the ways in which biodiversity is being studied.

  8. Understand these terms and the relationships among them:

    biodiversity

    genetic variability

    species variability

    ecosystem variability

    keystone species

    population

    mass extinctions

    alleles

    mutations

    bioprospecting

    gene banks

    systematic biology

    taxonomy

    conservation biology

    hot spots

What are the material benefits of preserving biodiversity?

  1. Pharmaceuticals

  2. Food

  3. Wood and other biological products

  4. Genetic resources

  5. Ecosystem level benefits

  6. Other benefits

Pharmaceuticals - bioprospecting: the new gold rush

  • 80% of the people in less-developed countries rely heavily or entirely on drugs derived from natural sources (World Health Organization estimate). More than 20,000 species have been used for medicinal purposes.

  • Of the drugs used in the U.S., 25% are derived from plants, 13% from microorganisms (including many antibiotics), and 3% from animals. Overall, 41% of our prescription drugs have their active ingredients derived from living organisms.

  • Will technological advances in the pharmaceutical industry preclude further natural-products research?

  • According to the National Cancer Institute, over 70% of the promising anti-cancer drugs come from plants in the rain forest. See bioprospecting for new pharmaceuticals.

  • Who really benefits from the commercialization of biodiversity? In the early 1990's, germplasm from developing countries was worth $32 billion per year to the pharmaceutical industry. Now, many tropical countries are taking real steps to protect their interests. See Shaman Pharmaceuticals.

  • An experimental but promising anti-HIV compound called Prostratin has been isolated from Homalanthus nutans (Euphorbiaceae). This plant is only found in the tropical Pacific island of Samoa, where it has been long used in native herbal medicine. A recent agreement will return 20% of all commercial revenues from drugs developed from this plant to the native peoples of Samoa. See this article from Time magazine.

  • Relatively few flowering plants (that is, of the ones we know) have been examined for their medicinal properties. Up to 1992, only 2% (or 5,000 species) had been examined. A number of these have become multi-billion dollar commodities:

    • Digitalis (foxglove), for the cardiac stimulant digitoxin.

    • Cyclosporin, a powerful immunosuppression agent used in organ transplants, was discovered in a Norwegian fungus.

  • For more information:

Foods

  • Wild plant gene pools are important to augment the narrow genetic base of established food crops (by providing resistance to disease, improved agricultural productivity, and different environmental tolerances). Most improvements in agriculture will depend upon the survival of these "gene banks."

  • In 1970, 15% of the US corn crop was wiped out by leaf blight. Mexican wild corn (Zea diploperennis) is a wild relative of corn. It was discovered in the 1970's. It has the same chromosome number as Zea mays and exhibits perennial growth. It occupies 25 acres of cold mountain land, and was one week away from extinction! This weedy plant resistant to a number of serious viral corn diseases that infect Zea mays. Researchers have transferred this viral resistance to corn. It may also be possible to produce perennial corn.

  • Many presently underutilized food crops have the potential to become important in the future. Remember: the relatively few species currently cultivated have had lots of research and selective breeding applied to them!

  • For more information:

Wood and other biological products

The potential products obtained from biological resources are endless. Some examples include:

  • fuel, construction, paper production

  • adhesives from barnacles

  • fibers from spider silk

  • antibiotics and pesticides from microorganisms

Ecosystem level benefits

  • Protection of water resources (vegetation regulates and stabilizes water runoff and increases water yield and quality).

  • Soil formation and protection (helps in the formation and maintenance of soil structure and quality, the retention of moisture and nutrient levels, and the prevention of erosion).

  • Pollution breakdown and absorption (bacteria and other organisms breakdown pollutants; wetlands can act as filters).

  • Recovery from unpredictable events (primary and secondary succession). Degraded ecosystems are less likely to recover from natural and man-made disasters (genetic variability is depleted and extinctions occur). Biodiversity promotes stability.

  • The removal or disturbance of one part of an ecosystem could affect the functioning of many other parts--recall the intricate web of life.

Keystone Species

What are they, and how are they related to biodiversity?

A keystone species is one that affects the survival and abundance of many other species in a community. Its removal results in a significant shift in the composition of a community, and sometimes even the physical structure of the environment.

If the keystone species is returned, the community can be restored.

  • For more information:

How do we study biodiversity?

Taxonomy & Systematic Biology-- To understand genetic diversity and genetic relatedness for the construction of evolutionary histories and to understand how species arise.

Much of our knowledge of biodiversity comes from the basic activities of systematic biologists, namely the discovery, inventory, and description of new species, the determination of their characteristics and evolutionary relationships to other species, and the organization of this knowledge into classification systems. These classifications are powerful predictive tools that help us to understand, maintain, and effectively utilize this great biological wealth.

  • The All Species Foundation, is a non-profit organization dedicated to the complete inventory of all species of life on Earth within the next 25 years - a human generation.

  • Integrative Biology 260 (formerly Plant Biology 260) introduces the principles and methods of identifying, naming, and classifying flowering plants. It includes a survey of selected flowering plant families and provides information on their interrelationships. The course meets three times a week for lecture and once a week for a two-hour lab. 4 credit hours (counts for Advanced Hours in LAS). Click here for some comments on why you might want to take this course.

Ecology & Conservation Biology-- The study of the interrelationships of organisms and their environment. How to protect and conserve populations, species, and ecosystems under the growing pressure of human habitation.

  • Biodiversity Hotspots from Conservation International. The 25 richest and most threatened reservoirs of plant and animal life on Earth. The 25 biodiversity hotspots contain 44 percent of all plant species and 35 percent of all terrestrial vertebrate species in only 1.4 percent of the planet's land area.