5/31/24 - Lecture 30/31: The History of Life on Earth Flashcards
Origin of life
The first life on earth was probably archaea or bacteria in deep sea vents. They were chemoautotrophic (no sunlight) and used anaerobic respiration
~3.8 billion years ago
Evolution of photosynthesis
Cyanobacteria - photosynthesis produces O2 as a “waste product”
~2.5 billion years ago
The Cambrian Explosion
Rapid appearance of most modern aquatic animal phyla in ~40 million years (at this point everything lived in water)
Key innovations: predators, eyes, sexual reproduction
~542-488 million years ago
Silurian period
The rise of land plants and jawed fishes
~444-419 million years ago
Devonian period
Land tetrapods
~419-359 million years ago
Carboniferous period
Very swampy: ferns, horsetails, gymnosperms (no flowers yet)
Also the time of the giant dragonflies
~359-304 million years ago
End Permian mass extinction
Where our fossil fuels come from
252 million years ago
Triassic period
Small dinosaurs
252-201 million years ago
Jurassic period
First flowering plants
201-145 million years ago
Cretaceous period
Big dinosaurs
145-65 million years ago
End Cretaceous mass extinction
Asteroid, 75% of all species go extinct, including all non-avian dinosaurs
65 million years ago
Early Cenozoic period
Mammals explode (130 new mammal genera in just 10 million years)
65 million years ago
Radiation of flowering plants and insects
Key innovations opened up new niches (nectar and fruit). Coevolution between plants and insects created adaptive radiations in insects too
65 million years ago
Cenozoic to Pleistocene climate change
Things were warm and swampy for a long time but began to cool off
Pleistocene period
Lots of cool megafauna in North America (most now extinct) 2.6 million years ago- 11.7 thousand years ago
