Chicken

## Evolutionary Timeline of the Chicken The chicken (Gallus gallus domesticus) traces its lineage back to theropod dinosaurs, evolving through major environmental shifts and human domestication. Key pressures include mass extinctions, climate changes, and selective breeding. ### Key Milestones: - **~160-150 MYA (Late Jurassic)**: Birds evolve from theropod dinosaurs like Archaeopteryx, developing feathers and flight capabilities amid lush, forested environments. - **~66 MYA (Cretaceous-Paleogene Extinction)**: Non-avian dinosaurs perish; avian survivors, including early galliform ancestors, adapt to post-asteroid impact ecosystems with reduced predation. - **~50-30 MYA (Eocene-Oligocene)**: Galliformes diverge, with jungle-dwelling ancestors adapting to tropical forests and seed-based diets under cooling climates. - **~10,000-8,000 years ago (Holocene)**: Domestication from Red Junglefowl (Gallus gallus) in Southeast Asia, driven by human agriculture and selective breeding for traits like egg production.