BSC1010C: General Biology 1

Introduction Chapter

  • Module 1: Week 1-2
    • Overview of key themes and learning objectives in biology.

Learning Objectives

  • By the end of this section, you will be able to:
    • Identify and describe the properties of life.
    • Describe the levels of organization among living things.
    • Describe the 3 theories that form the framework for modern biological science.
    • Summarize the steps of the scientific method.
    • Compare inductive reasoning with deductive reasoning.

Key Themes in Biology

  1. What does it mean to say that something is alive?
    • Considering the characteristics and attributes defining life.
  2. Life is cellular: Understanding that all living entities are composed of cells.
  3. Life evolves: Recognizing the continual process of evolution within species.
  4. Life processes information: Understanding biological information transfer and its implications.

Definition and Scope of Biology

  • Biology: The study of life,
    • Encompasses:
    • Structure, function, growth, and interactions of living organisms.
    • Evolution from microscopic cells to global ecosystems.
    • Measurement: One micrometer (µm) = 1/1,000,000 of a meter.

Characteristics of Living Organisms

  • All living organisms share six fundamental characteristics:
    1. Cells:
    • All organisms are made of membrane-bound cells.
    1. Replication:
    • All organisms can reproduce.
    1. Growth and Development:
    • Involves processing hereditary information coded in genes, influenced by environmental factors.
    1. Metabolism Regulation:
    • All organisms acquire and utilize energy to maintain homeostasis.
    1. Response to Stimuli:
    • Organisms respond to internal and external signals.
    1. Evolution:
    • Populations of organisms continually evolve over time.

Levels of Biological Organization

Hierarchy of Biological Organization

  • Organized from smallest to most complex level:
    1. Atoms: Smallest unit of an element that retains its properties.
    2. Molecules: Chemical structures consisting of one or more atoms.
    3. Macromolecules: Large, complex molecules, essential for life.
    4. Organelles: Compartmentalized structures within cells serving different functions.
    5. Cells: Basic unit of life, capable of performing all life functions.
    6. Tissues: Groups of similar cells working together for specific functions.
    7. Organs: Composed of multiple tissue types, performing specific functions.
    8. Organ Systems: Combinations of organs working towards specific roles within an organism.
    9. Organism: Individual living entity.
    10. Populations: Group of individuals of the same species in a given area.
    11. Communities: Interacting populations within an area.
    12. Ecosystems: Combinations of living and non-living things in a region.
    13. Biosphere: The global ecosystem comprising all life on Earth and the environments in which they live.

Taxonomy and Classification

Linnaeus’ Taxonomic System

  • Established by Carolus Linnaeus in 1735.
    • Each organism is given a unique two-part scientific name (binomial nomenclature):
    • Genus: Closely related species.
    • Species: Individuals that regularly breed together or whose characteristics are distinct from other species.

Rules of Nomenclature

  • Scientific names are always italicized:
    • Genus names: Always capitalized.
    • Species names: Not capitalized.
    • Example: Homo sapiens.

Taxonomy Hierarchy

  • Efforts to name and classify organisms:
    • Domain: Most inclusive group.
    • Three Domains:
    • Bacteria
    • Archaea
    • Eukarya
    • Kingdom under Eukarya includes:
    • Protista (mostly single-celled eukaryotes)
    • Fungi
    • Plantae
    • Animalia
  • Taxonomic rank order: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.
  • Mnemonic: "King Philip Came Over For Good Soup."

Theories in Biology

Core Theories

  1. Cell Theory:
    • All living things consist of cells.
    • All cells arise from preexisting cells.
  2. Theory of Evolution:
    • All species are related by common ancestry.
    • Species characteristics can change over generations (descent with modification).
  3. Chromosome Theory of Inheritance:
    • Genetic information is encoded in genes, which reside on chromosomes.
    • DNA is the hereditary material.
    • Chromosomes are passed from one generation to the next.

Explanation of a Theory

  • A theory is defined as an explanation for a general class of phenomena supported by substantial evidence.
    • Different from everyday usage where