Glossary and References

Glossary

• Abiotic - The physical and chemical non-living factors in an environment.
  
  
• Annelids - A phylum that includes segmented terrestrial and aquatic worms.
  
  
• Bacteria - Single celled prokaryotic organisms that form the first layer of a biofilm.
  
  
• Biodiversity - The number of different species of organisms in a particular environment.
  
  
• Biofilm - A coating or covering on the surface of a living or nonliving substrate composed of organisms like bacteria, protozoa, algae, and invertebrate animals.
  
  
• Biotic - The living factors in an environment.
  
  
• Crustaceans - A class of arthropod with 10 legs, antennae, and a hard exoskeleton.
  
  
• Cnidaria - An animal phylum that includes hydra, sea anemones, jellyfish, and hydrozoan colonies.
  
  
• Entoprocta - An animal phylum that includes organisms with tentacles on a cup shaped body supported by a single stalk.
  
  
• Evenness (E) - A measure of how similar the abundances of different species are in the community.
  
  
• Larvae - Immature forms of organisms, that typically look different from the fully grown adult and are usually smaller than the adult or even microscopic.
  
  
• Mollusks - An animal phylum that includes bivalves ( mussels), snails, slugs, and nudibranches.
  
  
• Nematoda - An animal phylum that includes all roundworms.
  
  
• Phytoplankton - Drifting microscopic plants that trap the energy from the sunlight and are primary organisms in a marine food chain.
  
  
• Platyhelminthes - A phylum of animal that includes all flatworms.
  
  
• Protozoa - A Kingdom that includes only single celled organisms like amoeba, stentor, vorticella, colonial ciliates, etc.
  
  
• Rotifers - A phylum that includes organisms that have ciliated mouths and a retractable "foot" for anchoring.
  
  
• Shannon-Weiner index (H) - This diversity measure came from information theory and measures the order (or disorder) observed within a particular system. In ecological studies, this order is characterized by the number of individuals observed for each species in the sample plot (e.g., biofilm on a plexiglass disc).
  
  
• Simpson's index (D) - The probability that two randomly selected individuals in the community belong to the same category (e.g., species).
  
  
• Simpson's index of diversity (1 - D) - The probability that two randomly selected individuals in a community belong to different categories (e.g., species).
  
  
• Simpson's reciprocal index (1/D) - The number of equally common categories (e.g., species) that will produce the observed Simpson's index.
  
  
• Species - Organisms that are genetically related, similar physically, and can reproduce viable offspring.
  
  
• Species Richness - The number of different species found in a particular environment.
  
  
• Sessile - Organisms that remain attached to a substrate.
  
  
• Zooplankton - Microscopic aquatic organisms, including larvae, which are the first consumers in a marine food chain.

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References

• Krebs, C. J. 1989. Ecological methodology. Harper and Row, Publishers. New York. 654 pp.
  
  
• Hill, M. O. 1973. Diversity and evenness: a unifying notation and its consequences. Ecology 54:427-432.
  
  
• Odum, E.P. 1971. Fundatmental of ecology. W. B. Saunders Company, Publishers. Philadelphia. 574 pp.
  
  
• Odum, E.P. 1975. Ecology: The link between the natural and the social sciences. Holt, Rinehart and Winston, Publishers. New York. 244 pp.
  
  
• Peet, R. K. 1974. The measurement of species diversity. Annual. Rev. Ecol. Syst. 5:285-307.
  
  
• Simpson, E. H. 1949. Measurement of diversity. Nature 163:688.

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