10 of the Worst Extinction Events on Planet Earth

TL;DR

Ten worst extinction events in Earth's history, ranging from climate change to asteroid impacts.

Transcript

One of the realities of living on planet earth is that every species that exists or ever has existed did so while in the precarious position of always being in danger of extinction. While asteroids tend to come to mind when talking about extinction events, there are actually a number of other things that can, and have, caused them. So here are ten ... Read More

Key Insights

• 💆 Asteroid impacts, climate change, volcanic activity, and astronomical phenomena have all contributed to mass extinctions in Earth's history.
• 🥺 Extinction events can lead to significant reductions in marine life, vertebrates, insects, and plant species.
• ◀️ Human activities are causing ongoing extinctions, but advancements in technology offer potential solutions and the ability to reverse some extinctions.
• 🇹🇹 The Toba supervolcano eruption and the Cretaceous Tertiary impact had profound effects on human and animal populations.

Questions & Answers

Q: Which extinction event is believed to have been caused by a gamma ray burst?

The Ordovician Extinction is believed to have been initially triggered by a gamma ray burst, potentially caused by a hypernova about 6,000 light years away.

Q: What contributes to volcanic extinctions?

Volcanic extinctions occur due to intense volcanism, changes in atmospheric composition from volcanic gases, and resultant fires that alter the climate.

Q: What is a clathrate gun, and how does it cause extinctions?

A clathrate gun is a release of methane from seabeds during periods of oceanic warming or drops in sea levels. This release leads to changes in climate, ocean acidity, and contributes to extinctions.

Q: How are humans causing the Holocene Extinction?

Human activities such as habitat destruction, pollution, and the introduction of non-native species are driving the Holocene Extinction by creating competition and ecological imbalances.

Q: What caused the extinction event 2.45 billion years ago?

The Great Oxygenation Event, caused by the release of oxygen from cyanobacteria, led to the extinction of anaerobic life and changes in greenhouse gas levels, which triggered glaciation and further extinctions.

Summary & Key Takeaways

• The Ordovician Extinction: Occurred between 455 to 430 million years ago, killing 86% of all marine life; attributed to climate change and possibly a gamma ray burst.

• The Pliocene-Pleistocene Extinction: A minor event affecting marine life; possibly caused by an asteroid impact or a supernova damaging the ozone layer.

• The Volcanic Extinctions and Clathrates: Geologic extinctions caused by intense volcanism and clathrate gun releases of methane; potentially responsible for the worst extinction event, the Permian-Triassic.

• The Carboniferous Rainforest Collapse: Rapid growth of plants causing rainforests to break up, leading to extinctions and a drop in oxygen levels.

• The Cambrian Extinctions: Three successive extinctions in the Cambrian period, potentially caused by depleted oxygen in the oceans.

• Olson's Extinction: An unexplained extinction event that occurred 273 million years ago, leading to a significant reduction in species.

• The Holocene Extinction: The ongoing extinction event caused by human activities, with the potential for reversal through genetic study and species management.

• The Toba Supervolcano: An eruption around 75,000 years ago that may have caused a genetic bottleneck in humans and affected multiple species.

• The Cretaceous Tertiary Impact: The asteroid collision 66 million years ago, resulting in the extinction of three-quarters of all animal and plant life.

• The Great Oxygenation Event: The release of oxygen by cyanobacteria around 2.45 billion years ago, leading to mass extinctions and shifts in atmospheric gases.