Cretaceous-Tertiary extinction

Examples of Cretaceous-Tertiary extinction in the following topics:

• Evolution of Reptiles

  • These groups remained inconspicuous until the Triassic period when the archosaurs became the dominant terrestrial group due to the extinction of large-bodied anapsids and synapsids during the Permian-Triassic extinction.
  • The dominance of dinosaurs lasted until the end of the Cretaceous period, the end of the Mesozoic Era.
  • The Cretaceous-Tertiary extinction resulted in the loss of most of the large-bodied animals of the Mesozoic Era.
  • Pterosaurs, which existed from the late Triassic to the Cretaceous period (210 to 65.5 million years ago), possessed wings, but are not believed to have been capable of powered flight.
  • Edmontonia, an example of an extinct quadruped reptile, was an armored dinosaur that lived in the late Cretaceous period, 145.5 to 65.6 million years ago.

• Biodiversity Change through Geological Time

  • Biodiversity has been affected by five mass extinction periods, which greatly influenced speciation and extinction rates.
  • The Ordovician-Silurian extinction event is the first-recorded mass extinction and the second largest.
  • The causes of the end-Cretaceous extinction event are the ones that are best understood.
  • The Cretaceous-Paleogene (K-Pg) boundary marked the disappearance of the dinosaurs in fossils, as well as many other taxa.
  • Recovery times for biodiversity after the end-Cretaceous extinction were shorter, in geological time, than for the end-Permian extinction: on the order of 10 million years.

• Post-Cambrian Evolution and Mass Extinctions

  • The post-Cambrian era was characterized by animal evolution and diversity where mass extinctions were followed by adaptive radiations.
  • The end of the Permian period (and the Paleozoic Era) was marked by the largest mass extinction event in Earth's history, a loss of roughly 95 percent of the extant species at that time.
  • Another mass extinction event occurred at the end of the Cretaceous period, bringing the Mesozoic Era to an end.
  • Late in the Cenozoic, further extinctions followed by speciation occurred during ice ages that covered high latitudes with ice and then retreated, leaving new open spaces for colonization.
  • Differentiate among the causes of mass extinctions and their effects on animal life

• Evolution of Birds

  • During the Cretaceous period, a group known as the Enantiornithes was the dominant bird type .
  • These birds formed an evolutionary line separate from modern birds; they did not survive past the Cretaceous.
  • Along with the Enantiornithes, Ornithurae birds (the evolutionary line that includes modern birds) were also present in the Cretaceous.
  • After the extinction of Enantiornithes, modern birds became the dominant bird, with a large radiation occurring during the Cenozoic Era.
  • It did not survive past the Cretaceous period.

• Gnathostomes: Jawed Fishes

  • Two early groups of gnathostomes were the acanthodians and placoderms , which arose in the late Silurian period and are now extinct.
  • Although most members of this clade are extinct, living members include the less-familiar lungfishes and coelacanths .
  • The coelacanth, sometimes called a lobe-finned fish, was thought to have gone extinct in the Late Cretaceous period, 100 million years ago, until one was discovered in 1938 near the Comoros Islands between Africa and Madagascar.

• Evolution of Mammals

  • They are the only living synapsids as earlier forms became extinct by the Jurassic period.
  • After the Cretaceous–Paleogene extinction event wiped out the non-avian dinosaurs (birds are generally regarded as the surviving dinosaurs) and several other mammalian groups, placental and marsupial mammals diversified into many new forms and ecological niches throughout the Paleogene and Neogene, by the end of which all modern orders had appeared.
  • The sauropsids are today's reptiles and birds, along with all the extinct animals more closely related to them than to mammals.