Text readings in Life by Ricki Lewis:

• Chapt. 1: pg 8-12 (examples of the diversity of life)
• Chapt. 16: pg 361-366 (review mutations)
• Chapt. 18: pg 394 (names of species)
• Chapt. 20: pg 436-437 (populations and changes in a gene's frequency), 442-443 (mutations), 447 (genetic diversity), 449-451 (species extinction)
• Chapt. 36: pg 812-819 (environmental concerns and biodiversity)

For your primary reference on the subject, biodiversity, look at:
Biodiversity: An Overview from the World Conservation Monitoring Center. (This file has been downloaded to our server because it is very difficult to load from its own server).

Additional resources from the web with some possibly useful notes are found at the end of this outline.

AND, check out Christopher Lieggi's far-out extra credit Biodiversity page.

Objectives:

1. Define what biodiversity is and its relationship to genes, species, and ecosystems.

2. Describe the roles of sexual reproduction, meiosis, and mutation in the origin and maintenance of genetic variation in a population (if you can do this, you should be in great shape for the test next week!).

3. Have a basic working knowledge of the number of species known, the estimated number in existence, and how these numbers are distributed among some major groups of organisms.

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

5. Discuss the value and potential of biodiversity to humans and factors which complicate the issues.

Biodiversity has to be defined at several levels, in terms of genes , species , and ecosystems. (These links take you to the definitions in the major reading)

In each case, it is the dynamic process and what we see now is the product of hundreds of millions of years of evolutionary history.

Biodiversity increases when new genetic variation is produced, a new species arises, or a novel ecosystem (or habitat) is formed.

Biodiversity decreases when the genetic variation within a species decreases, a species becomes extinct, or an ecosystem (or habitat) is lost.

1. Genetic diversity

... designates the variety of genetic information contained in all of the individual plants, animals, and microorganisms in the world.
• It occurs within and between populations of the same species as well as between species. Individuals belonging to the same species are not identical genetically (though this does not necessarily mean that each and every individual must be sampled and preserved).

• Differences in the amount and distribution of genetic variation within a single species can be attributed to the enormous variety and complexity of habitats, and the different ways organisms have adapted to these habitats.

• Genetic diversity can be measured using a variety of DNA and protein-based techniques.
  It can also (in part) be cataloged based on visible traits. For example, of the 100,000 genes in humans, 10,000 are outwardly (visibly) expressed and vary from person to person. Such phenotypic differences include differences in race, eye color, height, etc.

By now you should be able to discuss genetic diversity based on sexual reproduction, meiosis, mutation and populations. As a review for the test next week ...

... designates the variety of living species.
• This question (what is a species?) is not readily answered, and many definitions exist. (see endnote.) Basically, "species" are different "kinds" of living or extinct organisms.

  Lewis defines a species as "a group of similar individuals that interbreed in nature and are reproductively isolated (see endnote and wait for the evolution lectures) from all other such groups.

• Systems for the classification of species go back at least 2500 years to the Greeks.

• How many species are there?

  	Number Described	Estimated to be Discovered
  Viruses	5,000	about 500,000
  Bacteria	4,000	400,000-3 million
  Fungi	70,000	1-1.5 million
  Protozoans	40,000	100,000-200,000
  Algae	40,000	200,000-10 million
  Flowering plants	250,000	300,000-500,000
  Vertebrates	45,000	50,000
  Roundworms	15,000	500,000-1 million
  Mollusks	70,000	200,000
  Crustaceans	40,000	150,000
  Spiders and mites	75,000	750,000-10 million
  Insects	950,000	8-100 million

  Taken from: Systematics Agenda 2000: Charting the Biosphere. For more discussin and examples, see the endnote.

• An estimated 1.6 million species have been described to date.

• Estimates for the total number of species vary from 10 to 100 million.

• Species diversity is not evenly distributed across the globe. Species richness is concentrated in equatorial regions and decreases as one moves to the poles (or increases in altitude).

  Fifty to ninety percent of all species are found in the wet tropical rainforests, a region that comprises only 7% of the Earth's land surface. Why? [A question "to think about" and answer on Web Crossing.]

... designates the variety of habitats, biotic communities, and ecological processes occurring within and between different ecosystems (e.g. energy flow, water and nutrient cycling, succession, competition, mutualism--the interactions among species and between species and their environments).
• This diversity is found with respect to habitats, populations, communities and entire ecosystems.

• Ecosystem diversity is harder to measure than species or genetic diversity, partly because ecosystems themselves are harder to define. Nevertheless, it is a pre-condition for species and genetic diversity.

Reduction of biological diversity

For additional viewpoints (all positive), check Endnote 9.

1. Pharmaceuticals

• Facts as background:

  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 of organisms have been used for medicinal purposes.

  Of the drugs used in the US, 25% are derived from plants, 13% from microorganisms (including many antibiotics), and 3% from animals. Overall, that is 41% of our prescription drugs which are derived from living organisms!

  Many of these known drugs cannot be manufactured synthetically (or, if they are, they do not work as effectively).

  Relatively few flowering plants (for which we have the most complete classification) have been examined for their medicinal properties. Up to 1992, only 2% (or 5,000 species) had been examined. But a number of these have become multi-billion dollar commodities:

  • Digitalis (foxglove) for the cardiac stimulant digitoxin.

  • Catharanthus roseus (rosy periwinkle) for vincristine & vinblastine - the most effective drugs for treatment of childhood leukemia and Hodgkin's disease. From Madagascar, this is the source of two of the most effective anticancer agents ever discovered.

  • Taxus brevifolia (Pacific yew) for taxol - used to treat ovarian and breast cancer.

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

  • Penicilin, of course, was also first isolated from bread mold.

• Questions and issues:

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

  Not likely, as natural diversity is valued for the "blueprint" it provides for new synthetic drugs. Some drugs (e.g., taxol) are so unusual structurally, that they would probably have never been discovered in the laboratory.

  Are rainforests really all that important for medicines, or do we just say they may provide cures for cancer and AIDS?

  According to the National Cancer Institute, over 70% of the promising anti-cancer drugs come from plants in the rain forest. (see, for example, Bioprospecting for new pharmaceuticals).

  Just who really benefits from the commercialization of biodiversity?

  In early 1990's, germplasm from developing countries was worth $32 billion per year to the pharmaceutical industry. (see Putting a price on indigenous knowledge.

  Is bioprospecting really just the latest form of "neo-colonial economic exploitation"?

  Sometimes, but many tropical countries are taking real steps to protect their interests and some companies are responding very responsibly. For example, see Shaman Pharmaceuticals.

• 30,000 or more plant species have edible parts; 7,000 species are grown and used as food by humans; 20 species feed the majority (90%) of the world's population; just 3 species are the major world-wide staples.

• Wild plant gene pool 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." (see endnote 10.)

• 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!

3. Wood and other products from biological resources

• fuel, construction, paper production
• new hybrids and varieties of ornamental plants developed and marketed
• adhesives from barnacles
• fibers from spider silk
• natural pesticides from microorganisms
• petroleum substitutes

4. Genetic resources

• Specific habitats (ecosystem diversity) are important for breeding and spawning.

• Some habitats are genetic reservoirs from which seed and other materials can be obtained.

• Biotechnological advances permit genetic engineering wizardry (i.e., the transfer of genes from one organism to another).

5. 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). What's happening to the tropical rain forests?

• Maintenance of ecosystem functioning and their contributions to biogeochemical cycles and food web stability.

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

• Recovery from unpredictable events. Biodiversity promotes stability. (see p. 818 in Lewis).

• recreation, research opportunities, education.

7. Ethics (it's just morally wrong).

Endotes

1. Here are some more links and a few notes about them. They may be useful to you (individually or collectively) as supplementary material for the lecture, or as resources for projects in your real lives or real majors.
   • World Resources Institute. This is a page similar to that in the main "Biodiversity" link, but it isn't organized into a single page. For some, it will be a better overview, and some of the parts of it are included as separate links in the main outline.

   • Someone at Cornell has put together an extensive list of links to general biodiversity resources. A similar (but different) listing is maintained in Finland as the Internet directory for biodiversity.

   • The Biodiversity Center is a rapidly loading intro to "The Defenders" online magazine or group of essays. One of these, an essay on biodiversity is a short read covering some of the main points of the main link for the lecture.

2. There has been alot of discussion about the definition of "biodiversity", partly because there are alot of scientists and non-scientists who are concerned about the future of the planet, and partly because various interests (i.e. industrial interests) claim (correctly or incorrectly) that what the are doing will not endanger anything. The definition may be important to you if you are interested in (1) teaching, (2) policy, politics or history, (3) law, (4) travel, (5) agricultural effects, or (6) international development, to name a few. Check these out:
   • Defining the "B" word from Defenders magazine

   • Definition from Defenders magazine (an essay by Douglas Chadwick)

3. For more discussion of the definitions of biological diversity, and for an interesting additional definition of "cultural diversity", check out The Diversity of Life from the World Resources Institute.

4. For an interesting discussion of just exactly what a species is, particularly if you have been a bird watcher or had to deal with one, try this consideration of the definition of a red crossbill.

   3a. "Reproductive isolation" can be accomplished many ways. Spatially - different species that could potentially interbreed might be separated by an ocean, or a mountain range or some other object or space too big for them (or their pollen) to cross. Temporally - different populations (or potentially interbreeding species) might be active, or emerge (insects), or bloom (plants) at different times of year. Physically (or physiologically) - reproductive parts might just not fit, or pollinators might not fit different sizes of flowers, or there might be chemical incompatibilites between the reproductive structures.

5. For more stuff on just how many species there are (and how fast they are becoming extinct), try these links:
   • How many species are there?

   • Relative numbers of described species in major taxa

6. For more discussion of biodiversity in ecosystems, check the WRI page on that, too.

7. The loss of biodiversity is a major concern to many well-known biologist/writers. For a quite readable essay by Edward O. Wilson (a famous Harvard biologist and author), check out The threatened biosphere.

   Here is more information on endangered species with specific links that might be useful for teachers, policy studies, and list lovers.

8. For more discussion on rates of extinctions, especially in the tropics (the most diverse region of the world) check Rainforest Action Network with links to rates of rainforest destruction

9. Further discussion of the reasons for saving biodiversity can be found in a series of essays by "well-known" biologists in The case for saving endangered species. One of the authors is May Berenbaum (UI Department of Entomology and spearhead of the Insect Fear Film Festival). For a short discussion of the same topics found in the main part of the outline, see How protecting endangered species protects you.
10. Food and biodiversity Nature's supermarket: Our food supply depends on biodiversity.

    Genetic diversity and corn In 1970, 15% US corn crop wiped out by leaf blight. Mexican wild corn (Zea diploperennis) is 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.