History of Life on Earth

Planetary Formation

Earth formed from planetesimal aggregation around 4.55 billion years ago.

Prebiotic Soup

The early oceans where organic molecules and macromolecules accumulated and formed spontaneously.

Reducing Atmosphere Hypothesis

Early Earth's atmosphere was rich in water vapor, supporting redox reactions for complex molecule formation.

Deep-Sea Vent Hypothesis

Molecules formed in temperature gradients at deep-sea vents, supported by evidence of ammonia formation.

Protobionts

Aggregates of molecules with boundaries, exhibiting characteristics like information storage and self-replication.

RNA World Hypothesis

The theory that RNA was likely the first genetic material, capable of self-replication and acting as an enzyme.

Chemical Selection

The process where molecules with advantageous properties increase in number within a population.

Stromatolites

Layered structures formed by cyanobacteria, significant for producing oxygen through photosynthesis.

Endosymbiotic Theory

Proposed that eukaryotic organelles originated from symbiotic prokaryotes that provided energy or nutrients.

Cambrian Explosion

A rapid increase in animal diversity during the Cambrian Period, leading to the emergence of the first vertebrates.

Mass Extinction

An event where a significant percentage of species are wiped out simultaneously due to environmental changes.

Cenozoic Era

The era following the age of dinosaurs, characterized by the dominance of mammals and flowering plants.