"An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth."
Periods in geological history when significant numbers of species went extinct, often due to major environmental changes or catastrophic events such as asteroid impacts or volcanic eruptions.
Geologic time scale: A timeline that divides Earth's history into different periods and epochs.
Fossils: The remains or traces of ancient life that can provide insights into past environments.
Biodiversity: The variety of living organisms on Earth.
Climate change: Variations in global temperature and weather patterns over time.
Plate tectonics: The movement of Earth's crustal plates that can cause changes in the environment.
Marine environments: The ecosystems and organisms that live in oceans and other bodies of water.
Terrestrial environments: The ecosystems and organisms that live on land.
Atmospheric chemistry: The study of the composition and behavior of Earth's atmosphere.
Paleoclimatology: The study of past climates and weather patterns.
Evolution: The process by which living organisms change over time in response to their environment.
Catastrophic events: Events such as volcanic eruptions, asteroid impacts, and earthquakes that can cause mass extinction events.
Extinction rates: The frequency and severity of species loss over time.
Ecological succession: The process by which ecosystems recover and evolve after catastrophic events.
Biogeography: The study of the distribution of living organisms on Earth.
Paleontology: The study of ancient life and fossils.
Geology: The study of Earth's physical structure and processes.
Evolutionary biology: The study of how species change over time in response to environmental pressures.
Genetics: The study of how traits are inherited and passed down from generation to generation.
Conservation biology: The study of how to protect and preserve Earth's biodiversity.
Anthropogenic impacts: The effects of human activities on the environment and ecosystems.
Ordovician-Silurian Extinction: Occurred approximately 443 million years ago, caused by a cooling climate resulting in the loss of shallow marine habitats, leading to the extinction of approximately 85% of marine life.
Late Devonian Extinction: Occurred approximately 372 million years ago, caused by a combination of factors including anoxic conditions, climate change, and asteroid impact. It resulted in the extinction of 70% of marine species.
Permian-Triassic Extinction: Occurred approximately 252 million years ago, considered the most massive extinction event in Earth's history. It was caused by volcanic activity and resulted in the extinction of approximately 96% of marine life and 70% of land species, including the extinction of the dominant species of the time, the trilobites.
Triassic-Jurassic Extinction: Occurred approximately 201 million years ago, caused by a combination of volcanic activity, climate change, and asteroid impact. It resulted in the extinction of approximately 20% of marine life and 50% of land species, including many large amphibians and reptiles.
Cretaceous-Paleogene Extinction: Occurred approximately 66 million years ago, caused by a massive asteroid impact, resulting in the extinction of approximately 75% of plant, animal, and marine life, including the dinosaurs.
Holocene Extinction: Ongoing, caused by human activity such as habitat destruction, hunting, and introduction of invasive species. This extinction event is still ongoing and has already resulted in the loss of many species, including the extinction of some iconic animals like the dodo and Tasmanian tiger.
"Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms."
"It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation."
"Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty."
"These differences stem from disagreement as to what constitutes a 'major' extinction event, and the data chosen to measure past diversity."
"An extinction event (also known as a mass extinction or biotic crisis)..."
"It occurs when the rate of extinction increases with respect to the background extinction rate..."
"Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms, whereas background extinctions occur at a relatively steady rate."
"In the last 540 million years..."
"The data chosen to measure past diversity" plays a role in estimating major mass extinctions.
"No, it occurs when the rate of extinction increases rapidly..."
"It is a widespread and rapid decrease in the biodiversity on Earth."
"Not necessarily, as there is disagreement as to what constitutes a 'major' extinction event."
"No, a sharp change in the diversity and abundance of multicellular organisms is necessary to identify an extinction event."
"It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation."
"An extinction event is widespread..."
"Disagreement as to what constitutes a 'major' extinction event, and the data chosen to measure past diversity."
"No, an extinction event occurs when the rate of extinction increases with respect to the background extinction rate..."
"In the last 540 million years..."
"The number of major mass extinctions in the last 540 million years range from as few as five to more than twenty."