Fundamental Biology and Evolution Insights

Aug 21, 2024

Biology Essentials - Lecture 5: Essential Characteristics and Conservation

Introduction to Life

  • Tree of Life: A representation of the evolutionary relationships among various biological species or entities.
    • Key Groups:
      • ARA (Archaea)
      • UKaria (Eukarya)
      • Bacteria
  • Key Insight: Humans are more closely related to ARA than to bacteria.
  • Commonality in Life: All life shares certain characteristics, e.g., DNA.

Key Concepts Discussed

1. Genetic Code

  • DNA:
    • Universal genetic material.
    • Found in all life forms.
    • Example: Genes from jellyfish causing bacteria to glow.
    • Interchangeability: DNA can be transferred among different organisms.
    • Suggests a common ancestor for all life.

2. Central Dogma

  • Overview:
    • DNA → RNA → Proteins → You
    • Process includes DNA replication, transcription, and protein synthesis.
  • Francis Crick: Key figure in understanding DNA's function.
  • Universality:
    • Applies to all life forms, including bacteria, despite different ribosomes.

3. Metabolic Pathways

  • Metabolism:
    • Conversion of energy within organisms.
    • Cellular respiration: Organic material + Oxygen → CO2 + Water.
  • Energy Coinage:
    • ATP production through pathways like glycolysis, Krebs cycle, and oxidative phosphorylation.
    • Fundamental pathways are shared across all life.

Eukaryotic Characteristics

  • Domains: Bacteria, Archaea, Eukarya.
  • Eukaryotic Cells:
    • Have nuclei.
    • Division of labor inside cells.

Ways Eukaryotic Cells Evolved

1. Endomembrane System

  • Internal Folding:
    • Increases surface area, enabling complex functions.
    • Includes structures like Golgi apparatus, endoplasmic reticulum.
  • Molecular Evidence:
    • Proteins show inverse placement inside and outside of cells.

2. Organelles

  • Mitochondria & Chloroplasts:
    • Result from endosymbiosis.
    • Resemble bacteria (own DNA, reproduce by binary fission).
    • Chloroplasts: Important for photosynthesis.

Conclusion

  • Evolutionary Solutions:
    • Once a solution is found, it is conserved and passed through the tree of life.
    • The fundamental characteristics decided billions of years ago are still conserved.