AST 111 Lecture Notes - Lecture 14: Hydrothermal Vent, Tunxis Community College, Absolute Dating

• School: Tunxis Community College
• Department: Astronomy
• Course: AST 111
• Professor: Bourne

Document Summary

Earliest life forms arose more than 3. 85 billion years ago, shortly after the end of heavy bombardment evidence comes from fossils, carbon isotopes, etc. Fossils in sedimentary rock relative ages (deeper layers formed earlier) and absolute ages (radiometric dating) Rock layers of the grand canyon record 2 billion years of earth"s history. The oldest fossils show bacteria-like organisms were present over 3. 5 billion years ago; carbon isotope evidence dates the origin of life to >3. 85 billion years ago. The origin of life on earth we all share common ancestry, and evolution through time. The fossil record shows that evolution has occurred through time darwin"s theory tells us evolution occurs through natural selection; theory supported by the discovery of dna (evolution proceeds through mutations) Mapping genetic relationships has led biologists to discover a tree of life includes plants and animals, and suggests likely characteristics of a common ancestor.