Question

1. Time scale of the earth. Which is the correct order?

a. Azoic era, Proterozoic era, Paleozoic era, Mesozoic era, Cenozoic era.

b. Proterozoic era, Paleozoic era, Mesozoic era, Azoic era, Cenozoic era

c. Azoic era, Cenozoic era, Proterozoic era, Paleozoic era, Mesozoic era

D. Paleozoic era, Mesozoic era, Azoic era, Cenozoic era, Proterozoic era

2. At the end of the Mesozoic Era (ca. 65.5 million years ago), there was a major catastrophic extinction of life on earth. Which of the following statements is true of this extinction period?

A. It was the only major extinction period on our planet.

B. It was the greatest extinction period.

C. It resulted in the death of all species of plants and animals.

D. None of the above.

Answer 1

1. a. Azoic era, Proterozoic era, Paleozoic era, Mesozoic era, Coenozoic era.

2. b. It was the greatest extinction period.

Cretaceous–Paleogene extinction event (End Cretaceous, K–Pg extinction, or formerly K–T extinction): 66 Ma at the Cretaceous (Maastrichtian) – Paleogene (Danian) transition interval.The event formerly called the Cretaceous-Tertiary or K–T extinction or K–T boundary is now officially named the Cretaceous–Paleogene (or K–Pg) extinction event. About 17% of all families, 50% of all genera and 75% of all species became extinct. In the seas all the ammonites, plesiosaurs and mosasaurs disappeared and the percentage of sessile animals (those unable to move about) was reduced to about 33%. All non-avian dinosaurs became extinct during that time. The boundary event was severe with a significant amount of variability in the rate of extinction between and among different clades. Mammals and birds, the latter descended from theropod dinosaurs, emerged as dominant large land animals.