🦠

Basic Biological Terms for Organismal Biology

Apr 7, 2025

Lecture Notes on Basic Biological Terms for Organismal Biology

Introduction

  • Presenter: Kim Velazquez
  • Topic: Important biological terms for organismal biology
  • Relevant for both general biology and biology 102 (focus on human pathogens)

Types of Organisms

Unicellular vs. Multicellular

  • Unicellular Organisms:

    • One-celled organisms
    • Functions are carried out by one cell
    • Microscopic, short lifespan, no cell specialization
    • Examples: Bacteria (prokaryotic), Protists (eukaryotic), some algae, yeast (fungi)
  • Multicellular Organisms:

    • Made of more than one cell
    • Specialized cells with specific functions
    • Macroscopic, longer lifespan
    • Examples: Animals, plants, most fungi

Reproduction

Asexual vs. Sexual

  • Asexual Reproduction:

    • Creation of identical copies without gametes
    • Examples: Yeast budding, Protists splitting
  • Sexual Reproduction:

    • Involves egg and sperm producing a zygote
    • Haploid egg and sperm, diploid zygote
    • Cells specialize and grow into the organism

Trophic Levels

Autotrophs vs. Heterotrophs

  • Autotrophs:

    • Produce their own food (producers)
    • Photoautotrophs: Use sun, photosynthesis (plants, algae)
    • Chemoautotrophs: Use chemicals instead of light
  • Heterotrophs:

    • Consume other organisms (consumers)
    • Types: Herbivores (primary consumers), Carnivores, Omnivores, Detritivores, Decomposers

Symbiotic Relationships

  • Symbiosis: Close relationship between different species
  • Types:
    • Predation: +/-, predator benefits, prey is harmed
    • Parasitism: +/-, parasite benefits, host is harmed
      • Ectoparasites (outside host), Endoparasites (inside host)
      • Important terms: Vector, Intermediate host, Definitive host
    • Competition: -/-, both species may be negatively affected
      • Principle of Competitive Exclusion
    • Commensalism: +/0, one species benefits, the other is unaffected
    • Mutualism: +/+, both species benefit
      • Example: Pollinators and plants

Other Important Terms

  • Aerobic vs. Anaerobic:

    • Aerobic: With oxygen
    • Anaerobic: Without oxygen
  • Obligate vs. Facultative:

    • Obligate: Must adhere to lifestyle (e.g., obligate aerobes must have oxygen)
    • Facultative: Can switch between conditions (e.g., facultative anaerobes)

Pathogens

  • Definition: Organisms or entities capable of causing disease
  • Types:
    • True/Strict Pathogens: Always cause disease
    • Opportunistic Pathogens: Cause disease under certain conditions (e.g., immunocompromised individuals)

  • These foundational terms will support further understanding in organismal biology and studies on human pathogens.