a bird’s eye view: flamingos and the scientific method marita davison ph.d student cornell...
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A bird’s eye view: Flamingos and the Scientific
Method
Marita DavisonPh.D StudentCornell University
Past Present
1996
Environmental ScienceEcology, Conservation, Sociology, Economics, Anthropology
2000
Smithsonian National Museum of Natural
HistoryCurriculum Development
2001
2002
Field collectionsCloud Forest
I am...
Ornithologist Limnologist
A few definitions...ECOLOGY“oikos” = house (i.e. the planet, our home)“logos” = study or knowledgeThe study of the relationship between living organisms & their environmentORNITHOLOGY“ornithos” = birdThe study of birds
LIMNOLOGY“limne” = lakeThe study of lakes, ponds, & other standing waters
And a few more...
Community: a group of interacting organisms living in the same place
Ecosystem: a community of organisms and their physical environment interacting as an ecological unit
Coral Reef Sonoran Desert
How does predatorabundance affect thenumber of species?
How does nutrient availability affect primary production?
test your hypothesis
The S
cienti
fic
Meth
od
make an observation
ask a question
do background research
construct a hypothesis
analyze & report results
1. Observations
•Flamingos are the most conspicuous organisms in Altiplano salt lakes
•Flamingos spend most of their time eating by grazing algae that has settled on the lake sediment surface
•Flamingos are the most abundant grazers in Altiplano salt lakes
2. Questions
What effect do flamingos have on Altiplano salt lakes? Sub-questions:
1. Do flamingos influence community structure? 2. Do flamingos influence ecosystem processes?
What would happen (ecologically) if flamingos disappear?
3. Background research
A. Library searchecological journals, books, popular articles
B. Internet searchactive researchers, photographs, videos, maps
C. Make contactsexperts in the field, potential collaborators
3. Background research
From Hurlbert & Chang 1983
Algae >2x more abundant when
flamingos absent
Protozoa >6x more abundant when
flamingos absent
4. Constructing a hypothesis
Hypothesis: a working explanation of observed facts that
leads to testable predictionsHypotheses must address your question of
interest, they are NOT questions themselves!
Prediction: a specific forecast of the expected outcome in the situation described in your hypothesis
Predictions must be measurable, and should result in either: (1) acceptance or (2) rejection
of the hypothesis
Question 1: Do flamingos influence community structure?
Hypotheses vs Predictions
Biodiversity will be higher when flamingos are present and lower when flamingos are absent
Flamingos impact biodiversity of their lake habitats
Question 2: Do flamingos influence ecosystem processes?
Flamingos affect the growth of algae in Altiplano salt lakes
Growth of algae will be higher when flamingos are absent and lower when flamingos are present
Find the hypothesis!
How to test a hypothesis
5. Hypothesis testing
Experimental design:Simulate extinction of flamingos by excluding them from certain areas in the lake
2 types of experimental plots:
Exclosure plots: flamingos excluded
Control plots: flamingos presentEach plot: 4x4 meters, 5 of
each type placed at 2 locations in the lake
5 pairs of plots (exclosure & control)
x4
Sampling
Samples obtained from each plot (E & C)
Community structureAlgae for identificationInvertebrates for identification
Ecosystem processesBiomass of algae (chlorophyll a)Biomass of of invertebrates