S25 - Biología 11 M2

Scientific Concepts, Discoveries, and Nature Phenomena Mentioned

Key Ideas and Vocabulary

• Biogenesis vs. abiogenesis
• Origin of life (Genesis) as a research question
• Evolution
• Organic compounds
• Cell membrane
• Miller–Urey experiment (autogenerated text repeats the name)

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Major Theories for the Origin of Life

Primordial Soup / Primordial Broth Hypothesis

• Early Earth had chemical compounds that could form organic molecules in an oxygen-free environment.
• Energy sources (e.g., lightning and solar radiation) drove reactions.
• Produces amino acids, the building blocks of proteins.

Panspermia (Theory of Panspermia)

• Life (or more specifically organic molecules) may have arrived on Earth via meteorites or comets.
• Meteorite studies reportedly found amino acids and other complex organic molecules.
• Implication: the basic ingredients for life could be widespread in the universe.

Hydrothermal Vent Theory

• Life may have begun around deep-ocean hydrothermal vents where hot, mineral-rich water exits the Earth’s interior.
• Extreme environments can host some bacteria (prokaryotes) today, suggesting early life could survive there.
• Vent energy could help drive molecular organization into more complex structures.
• Protection from harsh surface conditions, notably intense UV radiation before an ozone layer formed.

Coacervates Hypothesis

• Proposed that early organic compounds in water grouped into bubbles/droplets called coacervates.
• Coacervates are said to have cell-membrane-like properties.
• They could create small closed reaction environments, helping chemistry become more organized and leading toward more “cell-like” systems.

RNA World Theory

• Early life began with RNA before DNA and proteins.
• RNA can both:
  • Store information (genetic-like function), and
  • Catalyze reactions (enzyme-like behavior).
• RNA could replicate and mutate, enabling evolution.
• Over time, RNA may have given rise to proteins and eventually DNA as the long-term genetic storage molecule.

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Examples / “Thought Experiments” Used to Illustrate Theories (Methodology)

Example 1: Primordial Soup

• Heat a mixture of early-Earth-like compounds (water, methane, ammonia, hydrogen).
• Heat (analogous to sunlight and Earth conditions) increases molecular motion and interactions.
• Aim: formation of amino acids → building blocks of proteins → life.

Example 2: Coacervates

• Add oil drops to water to show oil forms bubbles instead of dissolving.
• Analogy: early organic molecules form droplets/bubbles (coacervates) that act like primitive membranes.
• Purpose: keep molecules together in a more controlled environment to support reactions.

Example 3: RNA World

• Compare RNA to a recipe:
  • Provides “instructions” to replicate (information storage).
  • Helps drive chemical processes (enzyme-like role).
• Over time, the system evolves toward more complex molecules (proteins, then DNA).

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Researchers or Sources Featured (Named in Subtitles)

• Alexander Oparin
• J. B. S. Haldane
• Stanley Miller
• Harold Urey