Earth History Lecture Practice Flashcards

A comprehensive set of practice flashcards covering Earth's geological history from its formation through the Cenozoic era, including major tectonic cycles, biological evolution, and climatic events.

How does the lecture define geology?

The study of Earth, its materials, processes, products, and history, including rocks, minerals, fossils, tectonics, climate, and the evolution of life.

What is the current accepted age of the Earth?

Approximately $4.5$ billion years.

Which principle of geology is summarized by the phrase "The Present is the Key to the Past"?

Uniformitarianism (also known as Actualism), developed by Charles Lyell.

What is the main principle used in stratigraphy to reconstruct chronological history?

The principle that younger rocks usually lie above older rocks.

Who developed the principle of Biostratigraphy, and what does it entail?

William Smith; it states that fossil assemblages succeed one another in a predictable order, allowing for the correlation of rock layers.

What theory regarding evolution was developed by Georges Cuvier?

Catastrophism, the idea that catastrophes caused extinctions and new species appeared afterward.

What percentage of Earth history is covered by the Precambrian?

Approximately $88\%$.

Name the three eons that comprise the Precambrian.

Hadean, Archean, and Proterozoic.

What are the three eras of the Phanerozoic Eon?

Paleozoic ("Ancient life"), Mesozoic ("Middle life"), and Cenozoic ("Recent life").

Who proposed the idea of Continental Drift, and what was the name of the supercontinent?

Alfred Wegener; Pangaea.

List the six stages of the Wilson Cycle.

1. Continental rifting, 2. Young ocean, 3. Ocean spreading, 4. Subduction, 5. Collision/orogeny, 6. Supercontinent formation.

What is the Giant Impact Hypothesis?

The most accepted theory for the formation of the Moon, stating a Mars-sized body collided with Earth and the debris formed the Moon.

What are Greenstone Belts and where are they primarily found?

Important Archean rocks containing metamorphosed basalts, komatiites, and sediments; they provide evidence for early tectonics.

Why are Komatiites common only in the Archean?

They are ultramafic volcanic rocks that require extremely hot magma ($\sim1600^{\circ}\text{C}$), and the Earth was much hotter during the Archean.

What is the chemical equation for the photosynthesis performed by Cyanobacteria in the Proterozoic?

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

What are Banded Iron Formations (BIF) and what do they indicate?

Alternating iron-rich and silica-rich bands that formed when dissolved iron ($Fe^{2}$) oxidized to ($Fe^{3}$) as oxygen appeared in the atmosphere.

What were the Ediacaran Biota?

The first large multicellular organisms, which were soft-bodied fossils including Dickinsonia, Charnia, and Kimberella, existing just before the Cambrian Explosion.

What characterized the Cambrian Explosion?

The sudden appearance of many animal phyla and the evolution of hard skeletons.

What is the significance of the Burgess Shale?

It is a famous fossil locality that shows exceptional preservation of soft-bodied organisms from the Cambrian period, such as Hallucigenia and Anomalocaris.

What was the Taconic Orogeny?

A mountain-building event along eastern Laurentia during the Ordovician Period.

What is the significance of Cooksonia?

It was one of the earliest vascular plants, appearing in the Silurian Period.

What triggered the formation of coal swamps during the Carboniferous Period?

Warm, humid equatorial regions with massive forests and intense photosynthesis, leading to the burial of organic carbon.

How did the evolution of the amniotic egg impact life in the Carboniferous?

It allowed reptiles to reproduce away from water, reducing the dominance of amphibians.

What was the largest mass extinction in Earth history, and when did it occur?

The End-Permian Mass Extinction, resulting in the loss of $\sim90\%$ of species.

Name the three divisions of the Triassic in the Germanic Basin.

Buntsandstein (continental), Muschelkalk (shallow marine), and Keuper (deltaic/continental).

What is Archaeopteryx and why is it important?

A Late Jurassic fossil that shows the transition from dinosaurs to birds, featuring feathers, wings, and reptilian teeth/tail.

What caused the exceptionally high sea levels during the Cretaceous?

Intense mid-ocean ridge activity.

What are the two primary causes cited for the K-Pg (End-Cretaceous) Mass Extinction?

The Deccan Traps volcanism in India and the Chicxulub asteroid impact in Mexico.

What was the PETM (Paleocene-Eocene Thermal Maximum)?

A rapid global warming event where ocean temperatures increased by $\sim8^{\circ}\text{C}$ due to methane release or $CO_2$ increase.

What was the Messinian Salinity Crisis?

An event $\sim6$ Ma where the Mediterranean became isolated, evaporated, and formed giant deposits of evaporites.

What are the Milankovitch Cycles?

Climate controls based on orbital variations, including Eccentricity (orbit shape), Obliquity (axial tilt), and Precession (wobble).