Earth's Ages - Random Facts Trivia Quiz

Answer: 540 million y ago

The Paleozoic era is set between two major events in the history of animal life: the Cambrian 'explosion', when many of the animal groups first appeared and the Permian mass extinction, the largest of all extinctions. In the beginning life only manifested itself in the oceans but in some 200 million years the animals invaded the land, where they settled for good at the end of the era. Based on paleontologic and stratigraphic criteria, the Paleozoic is divided in 6 periods.

Answer: all of them

During the Cambrian, the landmasses were concentrated in the Southern Hemisphere and then started drifting towards the north. Life 'exploded' in the Cambrian as most of the major groups of animals first appear in the fossil records. The period ended with a mass extinction (although several other took place in the 40 million years span) probably caused by the glaciation in early Ordovician or the cooling and depletion of oxygen in marine waters.

Answer: trilobites

Trilobites were a successful group of arthropods, counting over 15000 species, which populated the Paleozoic oceans for almost 300 million years. They are well known to paleontology because their hard shells were excellently preserved. Their name comes from the three lobes that make up their body: the axial lobe and the right and left pleural lobes.

Answer: Caledonians

The Caledonian orogeny raised the mountains of Scandinavia, Greenland, Scotland, Wales and the northern part of the Appalachians. Most of these mountains have become platforms, due to the long erosion process.

Answer: Pterapsids

Pterapsids were small torpedo-shaped fish with pointed snouts. A bony shield protected the front of the body and the head. They had no fins and a jawless mouth beneath the head. They lived both in salty and fresh water; their fossils were found in Devonian rocks from North America and Europe.

Answer: the forming of coal deposits

The warm and wet climate from the beginning of the Carboniferous led to the growth of a rich and luxurious flora consisting of calamites, seed ferns, cordaites and other tree-like plants. These formed dense forests, set up in swampy areas. The land was gradually sinking and the sea periodically covered the forests.

When this happened, the plants did not rot, but instead formed peat. This eventually would become coal deposits. The name of the period means 'carbon bearing'.

Answer: 90%

The Permian ended with the largest mass extinction in Earth's history, perhaps caused by volcanism or glaciation. 50% of all animal families died out, as did many of the trees. In the seas, the outcome was even more catastrophic, as over 90% of all marine creatures became extinct. Not even the long-lasting trilobites were spared.

Answer: Age of Dinosaurs

The Earth in the Mesozoic era was quite different from how know it today. First of all, the continents were still joined together at the beginning of the era and they would gradually break up towards the end. The climate was warmer and milder and the sea level was higher.

It was the age of reptiles as they ruled the land (dinosaurs, crocodiles, placodonts), the seas (nothosaurs, ichthyosaurs, plesiosaurs, pliosaurs, mosasaurs) and the skies (pterosaurs). However, the Mesozoic also witnessed the birth of the first mammals and birds, which would later prove better adapted and would 'cheat' the mass extinction at the end of the era.

Answer: Pangaea

Pangaea was formed in the Permian as the merger of all the Earth's land masses. This supercontinent endured through the Triassic and it eventually began to break up at the end of this period into a northern continent - Laurasia and a southern continent - Gondwana, separated by the Tethys Sea.

This theory, proposed by German geologist Alfred Wegener (he also coined the name Pangaea - "All-Earth"), is supported by fossil evidence: some species' remains were found in all the continents.

Answer: Sauropods

Sauropods were gigantic plant eaters, which still hold all the records in terms of size, regarding the ground creatures. Not forgetting the popular Diplodocus, Apatosaurus or Brachiosaurus the relative recent discovery of Seismosaurus ("Earth-shaking lizard") amazes us yet again with the sheer proportions of the dinosaur world: it grew 40 meters and weighted 30 tones.

Answer: Yucatan Peninsula

The mass extinction at the end of the Cretaceous is famous for killing the dinosaurs. It is also known as the K-T extinction (K - standing for "kreta", meaning chalk, which was the main rock in Cretaceous and T - coming from Tertiary). However, the theories regarding the way it happened are diverse.

The most believable seems to be the one suggesting that death came from outer space. This theory proposed in 1980 by Luiz and Walter Alvarez, states that a giant asteroid (6-15 km in diameter) hit the Earth about 65 million years ago.

The aftermath would have been catastrophic and could have indeed led to the mass extinction. Besides the immediate effects of the impact - huge fires, high seismic activity, volcanic eruptions, tsunamis, acid rains, severe storms - the long term result would have been a worldwide winter, due to the dust and debris cloud spread around the world, blocking the sunlight.

It would have been dark and cold and so the plants would have died. Then the animals feeding on them would have died and then the animals that ate these animals would have starved too.

The evidence to support this theory is the 180 km wide and 1600 m deep impact crater, found in Yucatan and the layer of red-clay indicating the K-T boundary, visible in many rocks around the globe, which contains a massive amount of iridium (metal found in larger amounts at the core of the Earth and in meteorites from outer space). Other extinction theories blame epidemics and diseases, the changing of the flora, the mammals eating the dinosaurs' eggs, a supernova sending deadly rays and magnetic waves or even changes in the Earth's orbit. One thing is for sure: dinosaurs died at the end of Cretaceous as did their relatives, ichthyosaurs, plesiosaurs and mosasaurs in the seas and pterosaurs in the skies.

Answer: all of them

The Cenozoic, an era of great transformations for the Earth's crust, is dominated by the Alpine orogeny which raises the youngest mountains in all the continents. Linked with the orogenetic movements there are numerous volcanic phenomena. Profound changes take place in the repartition of the water and the land, as frequent epirogenic movements with sea transgressions and regressions occur.

The climate gradually cools, reaching the apex with the extensive Ice Age in the Quaternary (the largest known in the Earth's history - its ice caps covered one quarter of the Earth's surface).

The Cenozoic is also known as the 'Age of Mammals'. In general, the fauna draws nearer to the present fauna. The seas are now dominated by foraminifers, brachiopods and gastropods, which replace the ammonites and belemnoids from the Mesozoic seas.

The gigantic reptiles are extinct; the birds rule the sky and the mammals rule the land.

Answer: Pliocene

The Paleogene and Neogene are the subdivisions (periods) of the Cenozoic Era. The Paleogene is then divided in the Paleocene (65-54 million years ago - first large mammals and primitive primates appear), Eocene (54-38 million years ago - first rodents and primitive whales appear) and Oligocene (38-24 million years ago - cats, deer, rhinos, horses appear).

A minor extinction took place during this epoch, 36 million years ago. The Pliocene (5-1.8 million years ago), like the Miocene (24-5 million years ago) are both subdivisions for the Neogene epoch.

Answer: the glaciations

The glaciations occur periodically in Earth's history from a series of possible causes like the change of continental positions, the uplift of continental blocks, the reduction of CO2 in the atmosphere, astronomical variations etc. The major glaciations took place in the Late Proterozoic (800-600 million years ago), in parts of Ordovician and Silurian, in the Carboniferous and Permian and from the Late Neogene (Pliocene) to Quaternary (the last 4 million years).

This last Ice Age ended about 10000 years ago, simultaneously with the last mass extinction.

Answer: Smilodon

The famous sabertooth cats were some of the most ferocious predators ever to roam the Earth. Besides their distinctive huge canines, used for stabbing, slashing and slicing, their powerful face muscles ensured that the mouth could be opened to 90 degrees. Armed with this deadly arsenal, these felines have terrorized the Cenozoic era, preying mostly on elephants and mastodons. The many fossils found in the tar pits of Rancho la Brea from California show that sabertooths, unlike many other cats, hunted in packs.
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