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.