Eras & Periods
What is the Mesozoic Era?
The geologic era known popularly as the "Age of Dinosaurs," spanning the Triassic, Jurassic, and Cretaceous periods.
What are stromatolites?
Layered sedimentary structures created by ancient cyanobacteria, representing some of the oldest fossil evidence of life on Earth.
What are the dinosaurs?
An asteroid impact 66 million years ago triggered a global winter, wiping out this dominant group of land reptiles.
What is Pangea?
The most famous supercontinent in geologic history, which assembled near the end of the Paleozoic Era and later broke apart into our modern continents.
What is Carbon-14?
This radioactive isotope is used by scientists to find the absolute age of organic materials up to roughly 50,000 years old.
What is the Quaternary Period?
The current geologic period we live in, which began about 2.6 million years ago and is marked by repeated ice ages and the rise of modern humans.
What is oxygen?
This gas accumulated mass-scale in the atmosphere around 2.4 billion years ago due to photosynthetic microbes, sparking a massive climate shift but paving the way for complex life.
What is the Permian-Triassic extinction?
The Great Dying," this is Earth's most severe mass extinction event, wiping out over 90% of all marine species at the end of the Paleozoic Era.
Who was Alfred Wegener?
The German meteorologist who proposed the theory of "Continental Drift" in 1912, though he was widely ridiculed because he couldn't explain how the continents moved.
What are sedimentary rocks?
Out of the three major rock families, this is the primary type where paleontologists actually have a chance of finding well-preserved fossils.
What is the Precambrian?
This massive span of time covers roughly 88% of Earth's entire history, preceding the explosion of complex, hard-shelled life.
What is LUCA?
This 4-letter acronym represents the hypothetical primordial organism from which all modern cellular life on Earth descends.
What is the Chicxulub crater?
Located in Mexico's Yucatán Peninsula, this is the name of the massive impact crater left by the asteroid that ended the Mesozoic Era.
What is Panthalassa?
The name given to the vast, global super-ocean that completely surrounded Pangea during its existence.
What is the Law of Superposition?
This fundamental geological principle states that in an undisturbed sequence of rock layers, the oldest layer is at the bottom and the youngest is at the top.
What is the Carboniferous Period?
Named after coal, this Paleozoic period saw vast, swampy forests that eventually decayed into today's fossil fuel reserves.
What is panspermia?
The scientific hypothesis stating that the building blocks of life, or even microbial life itself, arrived on Earth from outer space via meteorites or comets.
What is the Ordovicium-Silurian extinction?
Earth's first major mass extinction (~444 million years ago) was likely caused by a severe ice age that caused sea levels to drop drastically, devastating marine environments
What is seafloor spreading?
This mid-20th-century discovery at underwater ridges provided the "conveyor belt" mechanism that finally proved continental drift to be true.
What are trilobites?
These extinct, hard-shelled Paleozoic marine arthropods are highly valued as "index fossils" because their rapid evolution helps scientists date rock strata.
What is the Cambrian Period?
The first period of the Paleozoic Era, famous for a sudden, massive evolutionary diversification of multicellular marine life.
What is the Ediacaran biota?
A bizarre group of soft-bodied, multicellular marine organisms that thrived in the late Precambrian, right before the evolution of skeletons and shells.
What are the Siberian Traps?
A massive volcanic province in Russia whose eruptions lasted for hundreds of thousands of years, pumping enough greenhouse gases to trigger the catastrophic Permian extinction.
What is Rodinia?
This ancient supercontinent formed roughly 1.1 billion years ago during the Proterozoic Eon, hundreds of millions of years before Pangea existed.
What is radiometric dating?
The general analytical technique of calculating a rock's exact numerical age by measuring the ratio of unstable parent isotopes to stable daughter isotopes.