CHAPTER 12 Flashcards
Species that are still present today are called ____ _____
extant species
whose members have all died off are called _____ _______
extinct species.
mass extinction event
When such a sudden and global loss of species occurs,
Palaeontologists generally recognize _ major mass extinctions
5
what are the five mass extinctions ?
The End Ordovician mass extinction
The Late Devonian mass extinction
The End Permian mass extinction
The End Triassic mass extinction
The End-Cretaceous Extinction
The End Ordovician mass extinction
affected only marine organisms, but at that time terrestrial organisms just begun to evolve.
The Late Devonian mass extinction
was also largely limited to marine organisms, including some early vertebrate clades.
The End Permian mass extinction
saw the largest loss of diversity in all of Earth’s history. Marine invertebrates were decimated, and this was the largest mass extinction of insects. On land, the synapsids were hard hit, as were the anapsids
The End Triassic mass extinction
saw the extinction of most lineages of pseudosuchian archosaurs, as well as many of the synapsids that had survived the End Permian extinction, and also affected marine life.
The End-Cretaceous Extinction
event occurred roughly 66 million years ago and killed all non-avian dinosaurs. In the oceans, large marine diapsids, died out, as did many varieties of corals, several forms of plankton, and ammonites. Pterosaurs went extinct as well. Although birds ultimately survived
how survived the late Cretaceous extinction
Mammals, turtles, crocodiles, amphibians, and fish
who had the best chances of surviving the Cretaceous extinction
Small animals, and particularly those that were semiaquatic
________ are a good example: these crocodile-like aquatic diapsids (completely unrelated to crocodilians, and another good example of convergent evolution at work
Champsosaurs
Close inspection of the grey clay layer revealed that it had
high concentrations of iridium. rock in tektites and shocked quartz.
Iridium
Iridium is a rare element on earth, but it is a common component of meteorites
tektites
Tektites are tiny pieces of rock that have been melted and then cooled.
shocked quartz
Shocked quartz is a form of the mineral quartz with a unique internal structure that can only be created by exposure to a powerful shockwave, like those created by a nuclear explosion or a meteorite impact.
where was the greater found
Chicxulub in Mexico’s Yucatán Peninsula
how was it found
The cenotes were arranged in a crescent shape many miles long. Each end of the crescent seemed to terminate at an edge of the peninsula.The cenotes were caused by a displaced portion of a limestone layer that had been pushed upwards, and that the structure did not actually end at the edges of the peninsula. Instead, it continued along the ocean floor and was actually a huge continuous ring
how long after the extinction of the dinosaurs was it when the ice age began
millions of years.
A mass volcanic outgassing of carbon dioxide and ash plumes
a suggested as a possible cause of the extinction. This scenario could potentially have affected the global climate enough to have caused the extinction of many kinds of organisms
were is there a high volcanic activity record
in the Deccan Traps of India at the end of the Cretaceous.
what’s the prevailing theory of Dinos going extinct
a very large meteorite struck the Earth in the Yucatan peninsula
what did this meteor cause
- huge tsunamis
- sent a cloud of super heated rock and dust = wildfires
- the heat of rain dust raised temps = cooked animals alive
- debris remained in the atmosphere for years
- haze reduced sunlight = less plants
- broken food chain
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