The concept of extinctions is relatively new; its acceptance faced resistance from religious and political beliefs.
Five major mass extinctions have significantly influenced the life we observe today.
Recoveries from these events often lead to new evolutionary directions, shaping modern biodiversity.
There are ongoing concerns about the potential for a sixth mass extinction due to human impact.
Radiation & Extinctions
Importance of studying the origins of animals and the evolutionary processes that led to diverse body plans.
Speciation and adaptive radiations, particularly among fish, mammals, and birds, along with amphibians colonizing land.
Major Extinctions
Explanation of the five main mass extinction events and their underlying causes.
Exploration of the responses of various ecosystems to these extinctions.
Geological Toolbox
Tools for tracing back geological and climatic events, such as fossil series, isotopes, and plate tectonics.
End-Ordovician Extinction (445-443 mya)
First known major extinction event.
Estimated loss: 85% of all marine species.
Late Devonian Extinction (372-359 mya)
Multiple extinction pulses, less defined than others.
End-Permian Extinction (251 mya)
Known as "The Great Dying"
Most significant extinction event, marked by massive biodiversity loss across both terrestrial and marine organisms.
End-Triassic Extinction (201 mya)
Transition marked by the rise of dinosaurs.
Cretaceous-Paleogene Extinction (66 mya)
Famous for the extinction of non-avian dinosaurs, likely caused by a meteor impact (Chicxulub crater) and volcanic activity.
Global temperature changes, marine habitat shifts, and geological events are common factors in extinction events.
Hypotheses for different extinction mechanisms: hypoxic conditions, marine eutrophication, climate changes, and bolide impacts.
Different responses:
Extinct ecological groups leave empty niches, allowing surviving organisms to diversify and adapt.
Recovery phases can last millions of years, impacting biodiversity significantly.
Discusses the ongoing Anthropocene extinction due to human activities that adversely affect megafauna and biodiversity.
Monitor global temperature increases related to extinction risks, suggesting we may be approaching significant biodiversity loss comparable to historical mass extinctions.