CHAPTER 1: The Themes of Biology and Scientific Inquiry
Themes Connect the Concepts of Biology
Biological Organization:
• Life can be studied at different levels of biological organization, ranging from
molecules to the entire living planet.
• Hierarchical organization includes:
• Biosphere: All environments on Earth that support life.
• Ecosystems: All living things in a particular area, along with non-living
components.
• Communities: Entire array of organisms inhabiting a particular ecosystem.
• Populations: All the individuals of a species living within the bounds of a
specified area.
• Organisms: Individual living things.
• Organs and Organ Systems: Body parts that perform a specific function.
• Tissues: Groups of similar cells that work together.
• Cells: Life's fundamental unit of structure and function.
• Organelles: Various functional components within cells.
• Molecules: Chemical structure consisting of two or more atoms.
Emergent Properties:
• New properties emerge with each step upward in the hierarchy of life.
• These properties are due to the arrangement and interactions of parts as complexity
increases.
Reductionism:
• Reducing complex systems to simpler components for study.
Systems Biology:
• Exploration of a biological system by analysing the interactions among its parts.
• Integrates different levels of biological organization.
Correlation of Structure and Function:
, • Structure and function are correlated at all levels of biological organization.
• Analysing a biological structure can give clues about what it does and how it works.
The Cell: An Organism’s Basic Unit of Structure and Function
• The cell is the smallest unit of organization that can perform all activities required for
life.
• Two main types of cells:
• Prokaryotic Cells: Lack a nucleus or other membrane-bound organelles.
• Eukaryotic Cells: Contain membrane-bound organelles, including a nucleus.
Life’s Processes Involve the Expression and Transmission of Genetic Information
Genetic Information:
• Cells contain chromosomes made partly of DNA, the substance of genes.
• Genes encode information for building proteins.
• DNA structure: Two long chains (strands) arranged in a double helix.
• Sequence of nucleotides in DNA is transcribed into RNA and then translated into a
protein.
Life Requires the Transfer and Transformation of Energy and Matter
Energy Flow and Chemical Cycling:
• Life requires energy transfer and transformation.
• Energy flows through an ecosystem, usually entering as light and exiting as heat.
• Chemical elements are recycled within an ecosystem.
Organisms Interact with Other Organisms and the Physical Environment
Interactions:
• Organisms interact continuously with their environments.
• Both organisms and environments are affected by these interactions.
• Feedback mechanisms regulate biological systems.
Evolution Accounts for the Unity and Diversity of Life
, Evolution:
• Evolution is the concept that living organisms are modified descendants of common
ancestors.
• Explains unity and diversity of life.
• Species have "descent with modification."
• Natural selection is a primary cause of descent with modification.
Classifying the Diversity of Life:
• Biologists classify life using a hierarchical system of taxonomy.
• Three domains of life: Bacteria, Archaea, and Eukarya.
Scientific Inquiry
Scientific Method:
• Science is a way of knowing and includes observation-based discovery and
hypothesis-based inquiry.
• Hypotheses must be testable and falsifiable.
• Experiments are conducted to test hypotheses.
Types of Data:
• Qualitative data: Descriptions rather than measurements. (In the format of words)
• Quantitative data: Recorded measurements, which can be organized into tables and
graphs. (In the format of numbers)
Forming and Testing Hypotheses:
• Hypothesis: A tentative answer to a well-framed question.
• Hypotheses lead to predictions that can be tested by observation or
experimentation.
Controlled Experiments:
• Control group and experimental group are compared.
• Variables are kept constant except the one being tested.
Theory in Science:
• Theory: Broader than a hypothesis, supported by a large body of evidence.
Modelling:
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