Study Notes for ENVR 1402: Principles of Science and Systems
Principles of Science and Systems: ENVR 1402
Overview
Course materials provided by McGraw Hill, 2021.
Content focus: Principles of Environmental Science, Systems Theory, Scientific Method, and the role of scientific consensus.
Agenda
Systems in Science: Explanation and usefulness.
Scientific Consensus and Conflict: Evaluation of role.
The Scientific Method: Description and function.
What is Environmental Science?
Definition: Systematic study of our environment and humanity's role within it.
Nature of the Field:
Interdisciplinary approach combining:
Natural Sciences
Social Sciences
Humanities
Objective: Understanding and addressing environmental challenges caused by human activities.
Systems Involve Interactions
Definition of Systems: Networks of interdependent components and processes with material and energy transfer.
Importance: Central concept in environmental science.
Examples: Not specified, discussions in class setting.
Components of a System
State Variables: Store resources like matter or energy.
Flows: Pathways allowing movement of resources between state variables.
Fig. 2.9 provides an illustration of state variables as compartments (e.g., plants and animals).
Significance: Helps diagnose disturbances within systems.
System Characteristics
Types of Systems
Open System: Exchanges matter and energy with surroundings—most systems are open.
Closed System: Self-contained with no exchange of matter or energy—rare occurrence.
Throughput
Definition: Describes energy and matter input, through, and output in a system.
Feedback Loops: Systems can experience:
Positive Feedback (bad) Loop:
Amplifies changes, leading to significant shifts.
Example: Trees store CO₂; decompose; further CO₂ released; increases global warming; worsens drought; leads to more forest dieback.
Negative Feedback (good) Loop:
Suppresses changes, aiding stability in systems.
Example: Predator-prey dynamics maintain ecosystem stability.
Stability of Systems
Homeostasis (there and then): The tendency for systems to remain stable and unchanging.
Example: Sweating when hot and shivering when cold.
Equilibrium (overall): Dynamic state where systems remain stable over time (e.g., normal body temperature ~98.6°F).
Disturbances can lead to:
Periodic Disturbance: Disruptive events like fire or flood.
State Shift: Significant changes that do not revert to previous state post-disturbance.
Resilience: Systems' ability to recover from disturbances.
Example: Grasslands regrowing after fire or drought.
Resilience vs State Shift
S-Coral reefs suffering from overfishing and warming stress, with difficulty returning to coral dominance.
S-Algal blooms leading to fish die-off; degradation persists even after nutrient reduction.
R-Mangrove trees regrowing after hurricane damage.
Emergent Properties
Definition: Characteristics of a functioning system that exceed the sum of its parts.
Example: A tree's qualitative aspects such as habitat provision, carbon storage, and soil stabilization exceed mere biomass.
Consensus and Conflict in Science
Scientific Consensus
Definition: General agreement among informed scholars, resulting from collaborative processes among scientists.
Example: Acknowledgment of climate change dynamics, despite variance in model predictions.
Paradigm Shifts
Definition: Significant changes in understanding when a majority of scientists agree that an existing explanation is inadequate.
What is Science?
Definition: Methodical process aimed to produce knowledge through careful observation of natural phenomena.
Nature of Science: Cumulative body of knowledge established through scientific inquiry to explain how the natural world functions and to address practical needs.
Basic Principles of Science
Empiricism: Knowledge derived from careful observation of observable phenomena. Understanding through empirical evidence.
Uniformitarianism: Processes remain consistent over time; current forces shape the future similarly to the past.
Parsimony: Preference for simpler explanations when two plausible options exist (Ockham’s razor).
Uncertainty: Knowledge evolves; theories must accommodate new evidence and be retested.
Repeatability: Experiments should yield consistent results when replicated; lack of reproduction may indicate flawed conclusions.
Proof is Elusive: Absolute proof is rarely attained; science remains open to new evidence.
Testable Questions: Theories must be evaluated through testable statements and hypotheses.
Skepticism and Accuracy in Science
Role of Skepticism: Scientists maintain caution regarding proposed explanations, holding ideas as provisionally true until substantial evidence emerges.
Reproducibility: The necessity for results to be replicable.
Accuracy: The correctness of measurements, while precision pertains to result repeatability and detail.
Peer Review: Essential in maintaining standards in study design and interpretation.
Reasoning in Science
Deductive Reasoning
Definition: Logical reasoning from general principles to specific outcomes.
Example: Plants needing sunlight to photosynthesize implies a plant in a dark closet will die.
Inductive Reasoning
Definition: Formulating general rules based on multiple specific observations.
Example: Observing birds’ seasonal appearances leading to the conclusion of seasonal migration.
Scientific Process/Steps
Some people add some dont but observation
Identify a question
Consult previous knowledge
Formulate a testable hypothesis
Collect data for hypothesis testing
Interpret results
Report for peer review
Publish findings
Class Discussed Scientific Process/Steps
observation
question
hypothesis
collecting data
methods
results
discussion
conclusion
Hypotheses and Scientific Theories
Hypothesis: A specific, testable claim or explanation based on observations.
Steps to formulating:
Observation (e.g., flashlight failure).
Hypothesis formation (e.g., "batteries are dead").
Predictive testing.
Gather data to confirm or refute the hypothesis.
Scientific Theory: Robust explanation derived from substantial evidence, regarded as trustworthy until proven otherwise. Different from popular usage of the term, which often implies speculation.
Probability and Statistics
Definition of Probability: Measure of likelihood of occurrence in the face of uncertainty.
Statistical Significance: Common threshold is 5% probability that observed results were random.
Sample size effects confidence levels; larger samples yield more reliable outcomes.
Normal Distribution
Definition: Many statistical tests assume a bell-shaped frequency distribution (Gaussian distribution) where the mean is central and values cluster around it.
Large random samples are likely to follow this distribution pattern.
Experimental Design
Types of Experiments
Natural Experiment: Observation of existing occurrences; suitable for long-term ecological studies.
Manipulative Experiment: Controlled experiments where certain conditions are deliberately altered.
Controlled Study: Comparison between treatment and control groups to identify causal relationships.
Techniques to avoid bias:
Blind Experiment: Researcher unaware of group assignments until analysis.
Double-Blind Experiment: Both researcher and subjects remain unaware of group assignments.
Variables in Studies
Dependent Variable: The outcome affected by other variables (on vertical axis in graphs).
Independent Variable: The factor manipulated (on horizontal axis in graphs).
Graphical Elements
Definition: Simple representations of phenomena that include physical models, charts, tables, and mathematical models.
Working with Excel for Assignments
Login to UTRGV.
Access M365 and open a new Excel sheet.
Navigate to Brightspace.
Find the Principles of Science & Systems tab.
Complete the Scientific Method and Historical Precipitation assignment as directed.
Upcoming Notable Dates
Readings: Geology and Earth Resources due.
Quizzes: CH2 Quiz due Sunday, 11:59 pm.
Assignments: Scientific Method & Historical Precipitation assignment due next week.