Earth and Life Science LC 2: Earth’s Subsystems

Vocabulary-based flashcards detailing the Earth's subsystems, interior layers, atmospheric composition, and key scientific pioneers based on the lecture material.

System

Any entity that consists of interrelated parts and functions as a unit.

Variables

Components of a system that change by interacting with one another to carry out various functions.

Model

A tool that simplifies a complex reality that permits prediction.

Mathematical/statistical models

Models made up of numerical and equation symbols used to predict an outcome.

Conceptual models

Mind imagery that we use to understand our physical world and experiences.

Open system

A system where matter and energy move freely in and out.

Closed system

A system with no substantial matter and energy move in and out of it.

Equilibrium

A state where a system accommodates change by balancing the input and output.

Feedback

The interactions that cause changes or adjustments between parts of a system.

Negative feedback

A feedback mechanism that creates a counter effect which tends to maintain equilibrium.

Positive feedback

A feedback mechanism that creates a reinforcement effect to a previous change.

Geology

The scientific study of the Earth structure, composition, and properties, coming from the Greek word $\text{geos}$ meaning Earth.

Oblate spheroid

The official shape of the Earth, which is not a circle or a perfect sphere.

Earth age

Approximately $4\text{ billion}$ years old.

Density

A measure of mass per unit volume used to compare how equal amounts of materials differ in mass.

Geosphere

The portion of the Earth that includes the interior and exterior structure, rocks, minerals, landforms, and physical processes on land.

Continental crust

Less-dense crust composed of aluminum silicate (felsic) rocks, ranging from $5\text{---}70\,km$ in depth.

Oceanic crust

Denser crust composed of iron magnesium (mafic) igneous rocks.

Mantle

The thickest layer of the Earth, made up of silicate rocks and divided into upper and lower sections.

Asthenosphere

A region in the upper mantle where rocks become ductile and behave like liquid allowing them to flow due to extreme pressure and temperature.

Outer core

A liquid layer made mainly of iron and nickel with a temperature of approximately $$4800\,^\circ\text{C}$.

Inner core

The innermost solid layer of the Earth with a temperature of approximately $$6900\,^\circ\text{C}$.

Mohorovicic discontinuity

The transitional boundary between the crust and mantle, discovered by Andrija Mohorovicic in $1909$.

Gutenburg discontinuity

The transitional boundary between the mantle and core, discovered by Beno Gutenburg in $1913$.

Lehman discontinuity

The transitional boundary between the outer core and inner core, discovered by Inge Lehman in $1929$.

Hydrosphere

The combined mass of water found on, under, and above the surface of the planet, consisting of $97.5\%$ saltwater and $2.5\%$ freshwater.

Water cycle

The flow of water into the other subsystems of the Earth, driven by heat energy from the Sun.

Atmosphere

The gaseous area composed of $78\%$ nitrogen, $20\%$ oxygen, and other gases like carbon dioxide and argon.

Troposphere

The first layer of the atmosphere closest to the surface where weather phenomena like clouds and storms occur.

Stratosphere

The second layer of the atmosphere containing the ozone layer and characterized by warmth from UV radiation absorption.

Mesosphere

A relatively cold layer of the atmosphere where gases are excited as they absorb heat energy from the sun.

Thermosphere

The outermost layer of the atmosphere that receives direct solar radiation and contains the ionosphere.

Nicolaus Steno

The Father of Geology who formulated the Law of Superposition.

James Hutton

The Father of Modern Geology who proposed uniformitarianism.

Alfred Wegener

The scientist who proposed the Continental Drift Theory suggesting continents were once joined as Pangaea.

Harry Hammond Hess

The scientist who proposed the theory of seafloor spreading.

James Lovelock

Developed the Gaia Hypothesis, proposing Earth functions as an interconnected system of living organisms and physical components.