ESCI409 Spheres

Extinctions

The permanent elimination of one or more species from the Earth. There is a background rate of extinction throughout geologic history, as well as mass extinction events where multiple species go extinct at the same time.

Great Dying

The largest mass extinction event in Earth's history, occurring around 252 million years ago (Permian-Triassic event). It led to the loss of approximately 75% of species, including up to 96% of marine species, and took ecosystems about 10 million years to recover.

Foraminifera

Single-celled protozoa that are less than 0.5 mm in size. They live in the oceans and make up a significant portion of Arctic and deep-sea biomass. Their distribution in the Meishan Permian-Triassic GSSP shows the impact of the mass extinction event.

Volcanic eruptions

The eruption of volcanoes, such as the Siberian traps, is believed to have caused the Great Dying. These eruptions released carbon dioxide and sulfur dioxide, leading to global warming, acidification of the ocean, and changes in precipitation of calcium carbonate minerals.

K-Pg event

The extinction event that killed off approximately 75% of plant and animal species, including non-bird dinosaurs, around 66 million years ago. It is believed to have been caused by an asteroid impact.

Asteroid theory of the K-Pg event

The theory proposed by Luis and Walter Alvarez that the extinction of dinosaurs and 75% of total species was caused by the impact of an asteroid. The impact would have created a large crater, thrown debris into the air, and caused months of darkness and cooling on Earth.

Volcanic impacts on climate

Volcanic eruptions can lead to temporary global cooling by releasing ash and sulfur dioxide into the atmosphere, which reflect sunlight back into space. However, their impact on greenhouse gas emissions and global warming is negligible compared to human activities.

Earth cycle

The interconnectedness of various Earth systems, including the geosphere, hydrosphere, atmosphere, and biosphere. These systems influence and depend on each other.

Precambrian period

4600mya to 541mya

Paleozoic period

541mya to 252mya

Mesozoic period

252mya to 66mya