EXTINCTION EVENTS

EVENTS OF EXTINCTION Species rise and become extinct throughout our natural history at a slower rate. In mass extinctions, the extinction rate dramatically increases as large populations of organisms die out in a relatively short period.Widespread catastrophic and global disastrous events can wipe out 25 to 99% of all living species. In between mass extinctions, many surviving organisms have opportunities to evolve as they occupy vacant niches. They may become a new species in a process called speciation.Unlike previous mass extinctions, the kind of extinction we face today is not caused by a natural catastrophe but by humans. In the last century, the increase in the number of extinct species multiplied because of human activities. People have raised the rate of the disappearance of species by as much as 1 000 times the background extinction rate. Mass Extinctions by SciShow Watch the video to know more about the major mass extinctions that had happened on Earth's history. FIVE (5) MAJOR MASS EXTINCTIONS 1. Ordovician-Silurian Mass Extinction 3rd most massive extinction in Earth's history85% of sea life was wiped outcause: A vast ice sheet caused the climate to change, which altered the chemistry of oceans.sample extinct organisms: 2. Devonian Period Mass Extinction * Three-quarters of all species on Earth died* Sea bed became devoid of oxygen; only bacteria survivedCause: Changes in sea level, asteroid impacts, climate change, and new kinds of plants messing with the soilSample extinct organism: (trilobites) 3. Permian Period Mass Extinction Also known as the Great Dying96% of species died outLife on Earth descended from the 4% that survivedcause: Asteroid impact, flood basalt eruptions, catastrophic methane release, a drop in oxygen levels, sea-level fluctuations (carboniferous dragonfly) 4. Triassic-Jurassic Period Mass Extinction Half of all the species, including large amphibians, became extinctcauses:Climate change, flood basalt eruptions, massive volcanic eruption, ocean acidity, and an asteroid impact (ammonites) Cretaceous-Tertiary Period Mass Extinction Extinction of the dinosaurs50% of all species died outcause: asteroid impact