History of Life on Earth Lecture Notes

Introduction

• Focus on General Biology for Senior High School, SDO Quezon City.
• Topic for Week 2: History of Life on Earth.
• Reminder for participants to prepare materials and gadgets for interaction.

Recap of Previous Session

• Last week: Genetic Engineering.
  • Classical Breeding vs. Recombinant DNA Technology.
    • Classical Breeding: Indirect manipulation of organism traits (natural processes).
    • Recombinant DNA: Direct study and manipulation of genes using molecular techniques.
  • Example given: Makapuno.

Essential Learning Competencies for Week 2

• Describe the general features of the history of life on Earth.
• Understand the geological time scale and major groups of organisms during those periods.

Overview of Earth

• Age of Earth: Approximately 4.6 billion years.
• Geological and biological changes affected landscapes and inhabitants.
• Exploration of Earth's history is crucial for understanding evolution.

Geologic Time Scale

Definition

• Record of life forms and geological events on Earth.
• Strata: Horizontal sections of rock layers studied by geologists.
• Paleontology: Study of fossils and ancient life forms.

Dating Methods

• Relative Dating: Comparing fossils to determine age.
• Absolute Dating: Using radioactive isotopes for exact age determination.

Major Divisions of Geologic Time Scale

1. Eons: Largest divisions.
2. Eras: Divisions within eons.
3. Periods: Divisions within eras.
4. Epochs: Smallest divisions.

Precambrian Time

• Covers 88% of Earth's history.
• Formation of Earth as a molten mass; no life forms initially.
• Different eons: Hadean and Archean.

Paleozoic Era

• Known as the era of ancient life (540 million years ago).
• Major periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian.
  • Dominance of invertebrates followed by the emergence of vertebrates and amphibians.
  • Significant events: First plants colonizing land, mass extinctions.

Mesozoic Era

• Era of dinosaurs (280 million years ago).
• Periods: Triassic, Jurassic, Cretaceous.
  • Major events: Evolution of mammals and flowering plants, splitting of Pangaea, mass extinction events.

Cenozoic Era

• Age of mammals (65 million years ago to present).
• Periods: Tertiary and Quaternary.
  • Tertiary: Mammals and primates evolve.
  • Quaternary: Ice Age animals, climate changes.

Summary of Lecture Points

• The geologic time scale is dynamic and based on major fossil events.
• The relationship between geological changes and biological evolution.
• Importance of studying geology and paleontology in understanding Earth's history.

Interactive Segment

• Students prompted to answer questions related to the lecture.
• Homework assignment: Create a creative output based on the geologic time scale using recycled materials.

Conclusion

• Acknowledgment of participants and reminder for feedback and support.
• Next lecture scheduled for the following Monday.