Study Guide Module 1: Biology & Scientific Inquiry

I. Introduction: Biology & Evolution

• Organisms are adapted to their environments.

• Adaptations result from evolution, the core principle of biology.

• Biology: Scientific study of life, asking questions and seeking science-based answers.

II. Concept 1.1: Common Themes of Life

• Five unifying themes:

  1. Organization

  2. Information

  3. Energy & Matter

  4. Interactions

  5. Evolution

III. Theme 1: Biological Organization & Emergent Properties

• Hierarchy of Structural Levels: Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere¹

• Emergent Properties: New properties arise at each level due to arrangement and interactions. (e.g., Photosynthesis in chloroplasts, brain function, ecosystem cycling). Not unique to life (bicycle example), but more complex.

• Reductionism: Studying complex systems by breaking them down.

• Systems Biology: Modeling whole systems based on interactions of parts. Predicting effects of changes.

• Structure & Function: Form fits function (e.g., leaf shape). Explained by natural selection.

• Cells: Basic units of structure and function.

  • Prokaryotic Cells: Bacteria & Archaea. No nucleus or membrane-bound organelles.

  • Eukaryotic Cells: All other life. Nucleus and membrane-bound organelles. Cytoplasm between nucleus and outer membrane.

IV. Theme 2: Genetic Information

• DNA: Heritable material, directs cell activities. Genes (units of inheritance) on chromosomes.

• DNA Replication: Copies genes for cell division.

• Gene Expression: DNA → RNA → Protein.

• Genetic Code: Universal (A, G, C, T nucleotides).

• RNA: Intermediary molecule, some types regulate gene function.

• Genomics: Large-scale DNA sequence analysis.

• Systems Biology in Genomics: Studying whole sets of genes and protein functions.

  1. High-throughput technology (e.g., DNA sequencing).

  2. Bioinformatics (data storage, organization, analysis).

  3. Interdisciplinary teams.

V. Theme 3: Energy & Matter

• Energy from the sun.

• Energy Transformation: Light → Chemical (photosynthesis) → Kinetic (muscle movement).

• Heat: Energy lost as heat during transformations.

• Nutrient Cycling: Within ecosystems.

• Energy Flow: Through ecosystems (light in, heat out).

VI. Theme 4: Interactions

• Organisms interact with each other and their environment.

• Examples: Plant roots & soil, plants & oxygen in air, tree & other organisms (microorganisms, insects, animals).

• Nutrient Cycling: Result of interactions.

• Human Impact: Global climate change due to CO₂ from fossil fuels. Greenhouse effect, global warming.

• Molecules & Organisms:

  • Enzymes: Catalyze specific chemical reactions. Metabolic pathways.

  • Regulation: Feedback mechanisms.

    • Negative Feedback: Product slows down the process (e.g., ATP).

    • Positive Feedback: Product speeds up the process (e.g., blood clotting).

VII. Theme 5: Evolution

• Evolution: Explains unity and diversity of life. Organisms are modified descendants of common ancestors.

• Concept 1.2: Evolution – Unity & Diversity

  • Diversity: Many species (1.8 million identified, 10-100 million estimated).

  • Taxonomy: Naming and classifying species (kingdoms, domains).

  • Three Domains:

    1. Bacteria (prokaryotic)

    2. Archaea (prokaryotic)

    3. Eukarya (eukaryotic)

       • Kingdoms: Plantae, Fungi, Animalia (multicellular eukaryotes).

       • Protists: Diverse, single-celled eukaryotes.

  • Unity: Shared characteristics (DNA, cell structure).

  • Charles Darwin: On the Origin of Species (1859).

    • Descent with Modification: Common ancestry, modifications over time.

    • Natural Selection: Mechanism for evolution.

      • Observations: Variation, overproduction of offspring, adaptation.

      • Inference: Differential reproductive success based on heritable traits.

  • Adaptation: Result of natural selection.

  • Evolutionary Tree: Branching diagram of relationships. Common ancestors.

VIII. Concept 1.3: Scientific Inquiry

• Science: Way of knowing, understanding the natural world.

• Inquiry: Asking and answering questions about nature.

• Scientific Process: Observation → Hypothesis → Prediction → Experiment/Test → Analysis → Conclusion. Repetitive process.

• Observations: Data (qualitative or quantitative).

• Inductive Reasoning: Specific observations → Generalizations.

• Hypothesis: Tentative answer, testable and falsifiable.

• Deductive Reasoning: General premises → Specific predictions ("If...then...").

• Testing Hypotheses: Experiments, observations. Cannot prove a hypothesis, only support it by failing to falsify it and falsifying alternatives.

• Scientific Theory: Broad explanation, supported by evidence. Different from a hypothesis.