BIODIVERSITY vs PATCH SIZE and TYPE
( Students may use the back of this paper to write down their data, remarks, variables and conclusions. )
PURPOSE: To help make students aware of the effect that patch size & type has on biodiversity.
BACKGROUND: Biodiversity can be defined as the degree of complexity in the kinds & numbers of life forms and their relationships to each other and their environment. The greater the BIODIVERSITY the greater the chance for survival.
- EXTINCTION: Biodiversity = variety = more different models = more choices for survival in changing environments.
- FOOD: Biodiversity = more choices = kinds of food, amounts of food, disease resistant food, nutritious food and environmentally adaptable food.
- MEDICINES: Over 40% of today's prescription drugs were originally derived from wild life-forms (mainly plants). At today's high rate of extinction (a 1000 plants per year?) we are undoubtedly losing many valuable medicines that we will never know.
- INDUSTRIAL RAW MATERIALS: Products such as wood, paper, rubber, oils, lacquers and 100's of others are derived from wild life-forms. As the extinction rate continues to accelerate our source of new raw materials shrinks.
- ENVIRONMENTAL ENHANCERS: Many environmental life forms play an important role in cleaning the earth's air, water and soil. Our numerous forms of pollution and environmental destruction are eliminating several of these environmental enhancers.
- PSYCHOLOGICAL & PHILOSOPHICAL VALUES: Do we have an inner need for variety? Do non-human life forms have any rights? Do we have the right to deprive future generations of their right to enjoy the benefits of biodiversity?
"The planet Earth is losing it's biodiversity at the fastest rate it has ever experienced. Do we have any obligation and/or ability to slow down or stop this loss?"
MATERIALS: Areas of flower patches (These patches may include a flowering bush or tree. It may include a patch of clover in a lawn. etc.) A pad or clipboard will also be needed for recording data.
PROCEDURE: (Descriptions: patch size = square meters & patch type = vertical or horizontal.)
Reference: E.O. Wilson,Biodiversity, National Academy Press, Washington, D.C. 1988
- Look for three or four flower patches of similar types which match one of the following conditions:
A. same basic flower type(s) heights are similar, but size of areas are different.
B. same basic flower type(s) with similar size areas but height (vertical form) of the flowers
NOTE: A Patch of flowers is an area of flowers that are separate from another area of flowers. A patch can be a single flower. The students should decide how to determine if two groups of flowers are separate. (They might decide to consider them separate if they don't come in contact with each other even on a windy day.) The students should also decide how to determine the patch size of their chosen "patches". They need to gain experience in choosing their own "metric" ( type of measurement ) for an experiment. It would even be advisable to have the students brainstorm the various ways of looking at the patch sizes that are labeled A. and B. above.
- Students should hypothesize how insect diversity will change from one patch size to another.
- Students should design their procedure for determining biodiversity after they have decided how to measure patch size. .They might choose to count the number of different insects that visit each patch in a specific amount of time. Knowing specific names is not necessary since the insects can be classified as bee 1, bee 2, beetle 1, etc. along with a brief characteristic.
" bee #1. Approximately 1 cm. long with 3 yellow bands on the abdomen."
" bee #2. Approximately 2 cm. long, all black. Flies very slowly."
" beetle #1 Approximately 2 cm. long, brown with 13 white stripes."
" ant #1 Approximately .5 cm. long, red body & black abdomen."
- After the observation period the total number of different species (not the total number of members of each species) should be recorded and plotted on a bar graph.
- Students should compare their results with other groups and summarize relationships seen between species diversity and patch size and type.
Suggested questions for further discussion:
1. "How does an insect perceive a patch size?"
2. "How does the various species diversity relate to energy transfer in the different trophic levels?"
3. "Is the difference in the distances between patch sites a more important factor than the patch size itself?"
(Adapted from: Dr. Brett Kent, Univ. of Maryland, Woodrow Wilson Biology Institute , 1991; by: T. Holtzclaw 1992)