Introduction to Ecology contd

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Introduction to Ecology contd
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The Fundamental Equation of Ecology Harper 1977

• ? N B D I E
• Change in Number Births Deaths Immigration
  - Emigration

John L. Harper 1925-2009
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Some Definitions of Terms

• environment - biotic and abiotic factors that
  influence organisms
• organism - individual living thing
• population - many individuals of one species
  living close enough to each other to potentially
  interbreed
• community - all interacting populations in a
  particular habitat - includes plants, animals,
  decomposer microbes - pond or forest community -
  in practice often used when 2 or more species
  discussed

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Some Definitions of Terms

• ecosystem - community plus abiotic factors -
  nutrients, water, soil, etc. - pond ecosystem
• habitat - place where microbe, plant or animal
  lives
• biosphere - the earth
• autecology - relation of individual organism to
  environment
• synecology - relation of populations or species
  to other populations or species

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How to study ecology?
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Scientific method is a repetitive process that
leads to the building of theories
Initial Observation
reasoning?
New Hypothesis
Hypothesis
New Experiment
Experiment
New Observation
Observation/ Data Analysis
Hypothesis not Supported
Interpretation
Final Hypothesis Supported
Theory
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Creosote and sage brush desert
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Diagram of desert plant root growth
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Statistics - a powerful tool for analyzing data

• 1. Descriptive Statistics - provide an overview
• of the attributes of a data set. These
  include
• measurements of central tendency (frequency
• histograms, mean, median, mode) and
• dispersion (range, variance standard
• deviation)
• 2. Inferential Statistics - provide measures of
  how
• well your data support your hypothesis and
  if
• your data are generalizable beyond what was
• tested (significance tests)

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Differences Between Means
Asks whether samples come from populations with
different means
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Observational Studies
pubs.usgs.gov/circ/circ1209/studyunit_design.htm
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Watering Hole showing Piosphere
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Model of Piosphere
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Lab Experiments
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Field Experiments
Pelvetiopsis
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Rothamsted, England Broadbalk Wheat Experiment
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Rothamsted, England Park Grass Experiment
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Natural snapshot experiment
Succession following avalanches at different
times
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Natural trajectory experiment
Eruption of Krakatau 1883