The presence of iridium in sedimentary rocks suggests a meteorite impact about 65 million years ago.
The Chicxulub crater off the coast of Mexico is evidence of a meteorite that dates to the same time.
Massive Meterorite Impact Evidence
Evidence of Meteroite Impact
Is a Sixth Mass Extinction Under Way? Consequences …
Scientists estimate that the current rate of extinction is 100 to 1,000 times the typical background rate.
Data suggest that a sixth human-caused mass extinction is likely to occur unless dramatic action is taken.
Mass extinction can alter ecological communities and the niches available to organisms.
It can take from 5 to 100 million years for diversity to recover following a mass extinction.
Mass extinction can pave the way for adaptive radiations.
Adaptive Radiations - New Environmental Opportunities …
Adaptive radiation is the evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities.
Mammals underwent an adaptive radiation after the extinction of terrestrial dinosaurs.
The disappearance of dinosaurs (except birds) allowed for the expansion of mammals in diversity and size.
Other notable radiations include photosynthetic prokaryotes, large predators in the Cambrian, land plants, insects, and tetrapods.
World-Wide Adaptive Radiations
Millions of years ago
Regional Adaptive Radiations
Adaptive radiations can occur when organisms colonize new environments with little competition.
The Hawaiian Islands are one of the world’s great showcases of adaptive radiation.
Hawaiian Islands -- Regional Adaptive Radiations
Close North American relative,
the tarweed Carlquistia muirii