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Exploring the Cretaceous Period: A Quiz on Earth's Past

This quiz explores key concepts and facts about the Cretaceous period, including its unique life forms, significant events, and environmental changes.

1 As is the case today, photosynthesizing organisms, such as phytoplankton and land plants, formed the primary part of the ________ in the late Cretaceous.

2 In the seas, rays, modern ________ and teleosts became common.

3 At the end of the Cretaceous there seem to have been no purely herbivorous or ________ mammals.

4 The first radiation of the diatoms (generally siliceous, rather than calcareous) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the ________.

5 ________ were common in the early and middle Cretaceous, but as the Cretaceous proceeded they faced growing competition from the adaptive radiation of birds, and by the end of the period only two highly specialized families remained.

6 The oceans and seas were populated with now extinct marine reptiles, ________ and rudists; and the land by dinosaurs.

7 The Liaoning lagerstätte (________) in China provides a glimpse of life in the Early Cretaceous, where preserved remains of numerous types of small dinosaurs, birds, and mammals have been found.

8 [8] This trend was due to intense volcanic activity which produced large quantities of ________.

9 This is evidenced by widespread black shale deposition and frequent ________.

10 The Cretaceous ended with one of the largest mass extinctions in ________, the K-T extinction, when many species, including the dinosaurs, pterosaurs, and large marine reptiles, disappeared.

💡 Interesting Facts

  • the extinct spider Eoplectreurys is the oldest described genus of Haplogynae, predating spiders from Cretaceous amber in Jordan and Lebanon.
  • the Cretaceous terrestrial crocodilian Araripesuchus is known from five distinct species, two from Africa and the other three from South America.
  • the extinct ant-like stone beetle Kachinus, found in Cretaceous amber, is similar in appearance to the modern genus Paraneseuthia.
  • the extinct rove beetle genus Ektatotricha is known from 15 beetles trapped in Cretaceous amber from Myanmar.
  • the newly-named Oryctodromeus, a genus of small herbivorous dinosaur from the mid Cretaceous of Montana, is the first dinosaur described as making burrows.
  • the Cretaceous mammal Argentodites is known only from a blade-like tooth with eight cusps arranged in a row.
  • the Cretaceous Malagasy mammal Lavanify is most closely related to a species from India.
  • Poricy Park in New Jersey is known for allowing limited collecting at its Cretaceous-era fossil shell beds.
  • Polar dinosaurs could have walked to Australia, because during the early Cretaceous the continent of Australia was still linked to Antarctica.
  • UA 8699, a broken molar from the Cretaceous of Madagascar, may be a fragment of the only Mesozoic marsupial from the southern continents.
  • Repenomamus may have been the largest mammal in the Cretaceous period and is the only mammal known to have eaten non-avian dinosaurs.
  • Trapalcotherium matuastensis is one of five species of mammals recognized among seven fossil teeth from the Cretaceous Allen Formation of Argentina.
  • New Caledonia, an island fragment of the sunken continent Zealandia since the Cretaceous, and home to the Kagu (pictured), has been likened to a "Jurassic Park".