geological eras recap

Actividad: Llena los espacios en blanco con la información correcta sobre los eones y períodos geológicos.

In the ​​ (a)   eon, from 4,000 to 2,500 million years ago, the first continents formed and the first forms of life, such as bacteria, appeared. This eon is known for the stabilization of the Earth's ​ (b)   and the start of ​ (c)   photosynthesis. The late heavy bombardment occurred early in this eon, from ​ (d)   to ​ (e)   billion years ago.

• Archean
• crust
• oxygen
• 4.1
• 3.8
• Mesozoic
• 6.0
• carbon dioxide
• mantle

The ​ (a)   eon, from 2,500 to 541 million years ago, is characterized by the oxygenation of the atmosphere and the development of multicellular life, including the first complex organisms like the Ediacaran biota. Significant events include the formation of the first ​ (b)   cells and the Snowball Earth hypothesis, which suggests global glaciations periods. The supercontinent ​ (c)   formed and then disintegrated during this eon.

• Proterozoic
• eukaryotic
• Rodinia
• Mesozoic
• prokaryotic
• Pangaea

Entering the Paleozoic era, the ​ (a)   period, from 541 to 485.4 million years ago, is known for the Cambrian explosion, a rapid diversification of animal life with hard shells. It marks the beginning of the ​ (b)   era. The first trilobites, such as ​ (c)   , appeared during this time.

• Cambrian
• Paleozoic
• Olenellus
• Jurassic
• Mesozoic
• Tyrannosaurus

The (a)   period, from 485.4 to 443.8 million years ago, saw the appearance of the first land (b)   and the evolution of marine life such as (c)   and mollusks. It is also known for the diversification of (d)   .

• Ordovician
• plants
• trilobites
• graptolites
• Jurassic
• sponges
• mammals
• algae

• The ​ (a)   period, from 358.9 to 298.9 million years ago, is famous for its coal forests and the appearance of the first reptiles. Known for the formation of extensive deposits of ​ (b)   . The supercontinent ​ (c)   began to form during this time.

• Carboniferous
• coal
• Pangea
• Jurassic
• granite
• Gondwana

Finally, the ​ (a)   period, from 298.9 to 252.2 million years ago, ended with the formation of the supercontinent ​ (b)   and a mass extinction that decimated much of life on Earth. This extinction event, known as the ​ Permian - ​ (c)   extinction, is one of the most severe in Earth's history.

• Permian
• Pangea
• Triassic
• Jurassic
• Gondwana
• Cretaceous