Biology of The Living Earth - Unit 1 Practice Test Vocabulary

Vocabulary flashcards covering key terms related to Earth's systems, atmospheric composition, solar system formation, and geological processes from Unit 1 LT 1 & 2.

Biosphere

The Earth system that encompasses all living organisms, including trees, insects, and deer.

Atmosphere

The layer of gases surrounding Earth, currently composed of nitrogen ($N_2$), water ($H_2O$), carbon dioxide ($CO_2$), and oxygen ($O_2$).

Hydrosphere

The Earth system that includes all liquid water features, such as Earth's oceans and Folsom Lake.

Geosphere

The solid portion of Earth comprising rock, soil, and geological structures like volcanoes and sedimentary rock.

Aerobic

Refers to processes, conditions, or organisms that require oxygen to exist or function.

Anaerobic

Refers to processes, conditions, or organisms that occur or survive in the absence of free oxygen.

Photosynthesis

The process by which plants use sunlight, atmospheric carbon dioxide ($CO_2$), and water ($H_2O$) to synthesize their own food.

Cyanobacteria

Photosynthetic microorganisms whose release of oxygen ($O_2$) into the early atmosphere significantly altered both the biosphere and geosphere.

Parts Per Million (ppm)

A unit of measure used to express concentration, such as atmospheric carbon dioxide ($CO_2$) recorded at $280\,\text{ppm}$ in 1750 and $424\,\text{ppm}$ in May 2023.

Cambrian Period

A geological time period occurring about 500 million years ago, during which atmospheric carbon dioxide ($CO_2$) exceeded $4{,}000\,\text{ppm}$.

Nebula

An interstellar cloud of dust and gas that marks an early stage in the formation of the solar system.

Accretion Disk

A rotating disk of gas and dust orbiting a massive central body during solar system formation.

Planetesimals

Solid objects formed in the early solar system that accreted over time to build planets.

Nuclear Fusion

The process powering stars like the Sun, occurring during solar system creation when atomic nuclei combine.

Solar Winds

A continuous flow of charged particles emitted outward from the Sun into space.

Rock Cycle

The geological process that creates, breaks down, and reshapes rocks, continually altering Earth's surface over long periods of time.

Radiometric Dating

A method used to determine the age of Earth materials by measuring the decay rate of radioactive isotopes.