Evolving_Concept_of_Life-Based on Emerging Evidence.pptx

This ppt talks about the evolving concept of life based on certain pieces of evidence.

1. Evolving Concept of Life Based on Emerging Pieces of Evidence Earth and Life Science – Module 1

2. Introduction • Life on Earth dates back 3.5–4.0 billion years ago • Scientists trace life using fossils, rock layers, and biomarkers • Understanding life’s history helps us predict the future

3. Early Earth • Earth formed: 4.6 billion years ago • Violent environment: meteorites, volcanic eruptions, zircon crystals formed • First oceans developed

4. First Life Forms • 3.5 BYA: Prokaryotes in stromatolites • Anaerobic (no oxygen) • 3.0 BYA: Cyanobacteria → photosynthesis, Oxygen Revolution

5. Eukaryotes & Multicellular Life • 2.0 BYA: First eukaryotes • 1.2 BYA: Multicellular organisms • Endosymbiosis theory: mitochondria & chloroplasts originated from bacteria

6. MAJOR ERAS OF LIFE

7. Paleozoic Era (542–251 MYA) • Explosion of life in oceans • Dominance of trilobites & cephalopods • Appearance of land plants & first vertebrates

8. Mesozoic Era (251–65.5 MYA) • Age of reptiles: dinosaurs ruled • Divided into Triassic, Jurassic, Cretaceous • First birds and mammals appeared

9. Cenozoic Era (65.5 MYA – Present) • Age of mammals • Evolution of Homo erectus and eventually Homo sapiens • Modern biodiversity

10. Evidence of Life’s History • Fossils – remains of organisms in rocks • Biomarkers – chemical traces of life • DNA evidence – similarities across all organisms suggest a universal common ancestor

11. Importance of Studying Life’s History • Helps us: - Understand Earth’s past - Predict and prepare for environmental changes - Develop medicine and conservation strategies

12. Conclusion • Life evolved from simple prokaryotes → complex multicellular organisms → humans • Evidence continues to shape our understanding of evolution • The study of life’s past is key to securing our future