Earth Science Exam Review

Flashcards to review key concepts related to Earth's atmosphere, geology, fossilization, and tectonic plates.

What is the importance of photosynthesis?

It produces oxygen.

What is the relationship between the atmosphere and hydrosphere?

Oceans allowed for life forms that produce oxygen, leading to its accumulation in the atmosphere and gas exchange that contributes to climate.

Why didn't the oxygen from Cyanobacteria accumulate in the atmosphere right away?

Chemical reactions with elements like iron consumed most of the oxygen.

What is the composition of Earth's current atmosphere?

Mostly Nitrogen and Oxygen.

What role did iron oxide play in understanding the development of Earth's atmosphere?

Its formation indicated the presence of atmospheric oxygen through reactions with dissolved iron.

What was the most significant contributor to the formation of Earth's first atmosphere?

Volcanic Outgassing.

What evidence suggests that comets may have contributed to Earth's hydrosphere?

Comets are made of ice; water-bearing clay minerals found on asteroids and impact craters on Earth.

How did changes in atmospheric composition impact global temperatures?

Increase and decrease of greenhouse gases correlate with temperature changes; more greenhouse gases lead to higher temperatures.

How did the presence of oxygen lead to the formation of the ozone layer?

Oxygen absorbed UV radiation, breaking O2 into individual oxygen atoms that bonded to form O3, creating the ozone layer.

What is the most significant difference between Earth's current atmosphere and its previous atmospheres?

The presence of oxygen.

How might volcanic eruptions impact the composition of the atmosphere?

By releasing ash and gases that affect climate patterns.

What is a potential long-term outcome of melting polar ice caps on atmospheric composition?

Increase in greenhouse gases affecting global weather patterns.

What evidence is used to determine the geologic time scale?

Divided into blocks by major geological events, seen in fossil records and radiometric dating data.

What are the four principles of relative dating?

Principle of Superposition, Original Horizontality, Cross-cutting Relationships, and Inclusion.

What is radiometric dating?

An absolute dating method comparing the amount of radioactive parent isotope to stable daughter isotope.

What is a half-life?

The time it takes for half of a radioactive parent isotope to decay into daughter isotopes.

What is an isotope?

Atoms of the same element with a different number of neutrons.

How is radiometric dating represented in a T-chart?

1 half-life = 50%, 2 half-lives = 25%, 3 half-lives = 12.5%, 4 half-lives = 6.25%.

How old is a rock sample with 25% of its original Potassium-40?

2.6 billion years.

How many half-lives have passed if 12.5% of the original parent isotope remains?

3 half-lives.

What percentage of parent isotope remains after 2 half-lives?

25%.

List the physical properties used to identify minerals.

Crystal Habit, Cleavage, Fracture, Hardness, Specific Gravity, Color, Streak, Luster.

How are igneous rocks formed?

From the cooling and solidification of molten rock (magma or lava).

What are intrusive and extrusive igneous rocks?

Intrusive rocks form from slowly cooled magma underground; extrusive rocks form from rapidly cooled lava.

What are the four types of composition of igneous rocks?

Felsic, Intermediate, Mafic, and Ultramafic, differing in silica content and color.

Describe the texture of fine-grained and coarse-grained rocks.

Fine-grained has small crystals due to fast cooling; coarse-grained has large crystals due to slow cooling.

How are sedimentary rocks formed?

Sediments are compacted and cemented together.

What are the three types of sedimentary rocks?

Clastic, Chemical, and Organic.

How do metamorphic rocks form?

From pre-existing rocks altered by high temperatures and pressures.

What are foliated and non-foliated metamorphic rocks?

Foliated have layers; non-foliated lack a layered structure.

What is a fossil?

Remains of once-living organisms.

What are the two main types of fossils?

Body fossils (preserving parts of organisms) and Trace fossils (evidence of activity or movement).

What can we learn from fossils?

Past organisms, environments, evolution, continental drift, mass extinction, and climate.

Define each type of fossilization: Preservation of Original Material, Carbonization, Mold, Cast, Permineralization.

Original Material: actual remains preserved; Carbonization: carbon residue left; Mold: impression left by decay; Cast: filled mold; Permineralization: minerals fill pore spaces.

Explain why not all organisms become fossils.

Fossilization is rare; most decompose before being preserved or are destroyed by natural processes.

What does 'anoxic' mean?

Without oxygen.

How do we determine behavior and diet from fossils?

By observing common features with living organisms today in the fossil record.

What are the characteristics of the inner and outer core?

Inner core is solid nickel and iron; outer core is liquid nickel and iron.

Where are the convection currents found in Earth’s interior?

In the asthenosphere.

What drives the movement of tectonic plates?

Convection currents.

What part of Earth's interior makes up the tectonic plates?

The crust and upper mantle, known as the lithosphere.

What are the two types of crust?

Continental and oceanic crust.