Module 5 Overview - Earth Environmental Science

Origins of Life on Earth

• Cell Theory: Life must come from lifeless matter.
• Yuri Miller Experiment: Tested the possibility of life's building blocks forming naturally.
  • Water vapor, methane, ammonia, hydrogen gas, and electrode used.
  • Results indicated organic material formation under Earth's early conditions.

Meteorites and Panspermia

• Meteorites: Provided unique Earth materials.
• Panspermia Theory: Life traveled on a meteor from another planet to Earth.
• Current Acceptance: Yuri Miller's findings more likely than panspermia.

Hydrothermal Vents

• Hot Vents: Too hot for life (~Iron, Copper Sulfate, Barium Sulfate).
• Alkaline Vents: Ideal temperature (~60°C) and essential mineral production.

Stromatolites

• Description: Layered organic matter, up to 3.4-3.5 billion years old.
• Formation: Microbes create waste, build layers over time.
• Importance: Insight into historical atmospheric conditions and photosynthesis.

Cyanobacterium and Atmospheric Change

• Cyanobacterium: Early life form, similar to chloroplasts.
• Impact: Increased oxygen levels, decreased CO2/water through photosynthesis.
• Oxidation Events (OEs): Significant changes in Earth’s atmosphere.

Development of Multicellular Life

• Early Life: Simple organisms like stromatolites and cyanobacterium.
• Bangiomorpha: First multicellular plant (~1200 million years ago).
• Bilateral Symmetry: Animals developed symmetrical traits (~523 million years ago).
• Evolutionary Arms Race: Emergence of armor, teeth, and eyes due to competition.

Transition to Land

• Early Land Plants: Stabilized soil, decreased erosion (~Devonian Period).
• Animal Evolution: From aquatic to terrestrial (~365 million years ago).
• Adaptations: Waxy leaves, leathery skin to reduce water loss.

Fossil Record and Formation

• Fossil Types: Trace fossils, molds/casts, replacement, permineralized, amber, and freezing.
• Preservation: Rapid burial essential, sedimentary rock preferred.
• Index Fossils: Vital for relative dating of geological layers.

Dating Fossils

• Methods: Stratigraphy, superposition, uniformitarianism.
• Important Events:
  • Cretaceous Extinction
  • Cambrian Explosion

Plate Tectonics and Evolution

• Tectonic Super Cycle: Continents drift and merge over time.
• Climate Impact: Continental formation reduces CO2, polar reflection cools Earth.
• Biosphere Evolution: Supercontinent formation linked to adaptive radiation of species.

Inquiry Questions

• Students are encouraged to reflect on and answer inquiry questions based on the lecture.
• Suggested structure: STEEL or PEEL paragraph for report-style answers.