- Carboniferous Period: about 360 to 286 million years ago (Paleozoic Era)
- Coal Formation: Extensive coal swamps formed, particularly in the Late Carboniferous, leading to vast coal deposits still mined today.
- Plant Life: Vast forests of giant lycophytes, horsetails, ferns, and seed ferns flourished.
- Amphibians: Dominant vertebrates, many growing large due to high oxygen levels
- Reptiles: First reptiles appeared, allowing colonization of more terrestrial environments.
| Mass Extinction Event | Period (Million Years Ago) | Probable Causes | Impact on Life |
| Ordovician-Silurian | 445 Mya | Global cooling, glaciation, sea level fall | 85% marine species extinct |
| Late Devonian | 375 Mya | Ocean anoxia, asteroid impacts, plant-induced cooling | 75% marine life lost, especially corals and fishes |
| Permian-Triassic | 252 Mya | Siberian Traps volcanism, global warming, ocean acidification | 96% marine and 70% terrestrial species extinct (largest) |
| Triassic-Jurassic | 201 Mya | Volcanic eruptions, climate change, rising CO₂ | 80% species lost, allowed dinosaurs to dominate |
| Cretaceous-Paleogene (K-Pg) | 66 Mya | Asteroid impact (Chicxulub), Deccan volcanism | 75% species extinct including non-avian dinosaurs |
Anthropocene extinction is the ongoing sixth mass extinction caused by human activities like deforestation, pollution, climate change, and overexploitation. Species are disappearing at rates 100–1000 times faster than natural levels.
The Geological Time Scale (GTS) is a system of chronological dating that describes the timing and relationships of events that have occurred during Earth’s history.Through its hierarchical structure, the GTS subdivides Earth’s history into eons, eras, periods, epochs, and ages, each representing distinct intervals of time characterized by specific geological and biological phenomena.
| Eons | Era | Period | Epoch | Age/Years before Present | Life/Major events |
| Phanerozoic Eon | Cenozoic 65 mn years to presentLatest era2 periodAge of mammals | Quaternary(2 mn year ago to present) | Holocene | 0-10,000 | Age of Human Evolution : Modern ManAgriculture and Domestication of animalongoing biodiversity loss, anthropocene impact |
| Pleistocene | 10,000-2 mn | mammals evolution → monkeys and homosapiensdevelopment of modern human behaviors | |||
| Tertiary(2-65 mn years ago) | Pliocene | 2-5 mn | emergence of early human ancestors | ||
| Miocene | 5-24 mn | First Homininae (humans and their ancestors, and chimps and gorillas).Warmer global temperature, expansion of grasslands and forests | |||
| Oligocene | 24-37 mn | Emergence of grasslands → elephants, cats etcForefather of man : Anthropoid Apes | |||
| Eocene | 37-58 mn | first grasses; rabbits and harespread of angiosperms (flowering plants) | |||
| Paleocene | 57-65 mn | adaptive radiation of mammalsSmall mammals : rat – mice | |||
| Mesozoic65- 245 mn year ago3 periods | Cretaceous | 65-144 mn | insects, modern mammals, and bird groups, first flowering plantK-T extinction → Extinction of Dinosaurs | ||
| Jurassic | 144-208 mn | Age of DinosaursFirst bird, first true crocodile, first true mammal evolved | |||
| Triassic | 208-245 mn | Frogs and turtles appeared First dinosaurs4th mass extinction | |||
| Paleozoic 245-570 mn6 periodsEnded with largest mass extinction | Permian | 245-286 mn | Reptile dominate, replace amphibians | ||
| Carboniferous | 286-360 mn | Amphibians diversify, first reptiles; vertebrates Coal Beds → coal forming forests | |||
| Devonian | 360-408 mn | Age of fishes, first amphibiansPrimitive forests | |||
| Silurian | 408-438 mn | Evolution of fish ⇒ Appearance of jawed fishes, coral reefsFirst trace of life on land : early vascular plants | |||
| Ordovician | 438-505 mn | Diversification of marine life → First Fish, Trilobites | |||
| Camberian | 505-570 mn | Cambrian explosion First marine invertebratesStill no terrestrial life | |||
| Proterozoic | Precamberian (Eozoic) | 570-2500 mn | Evolution of abundant soft bodied multicellular organism (arthropods) | ||
| Archeon | 2500-3000 mn | Life began in ocean : anaerobic bacteria By the end → Blue green algae and unicellular bacteria | |||
| Hadean | 3000-5000 mn | Stabilization of core and crust development of atmosphere and ocean (Rich in CO2 ) | |||
| Origin of starsSupernovaBigbang | 5000- 13700 mn | 5000 mn12000 mn13700 mn | Origin of the sunOrigin of Universe |
