Chemical Processes in Earth and Life Systems

Front

What biological process is responsible for introducing free oxygen to Earth’s atmosphere?

Back

Photosynthesis is the biological process that introduced free oxygen to Earth’s atmosphere.

Front

Why is it believed that life on Earth evolved in the oceans before appearing on land?

Back

Ocean water offered protection against harmful radiation until an atmosphere could form.

Front

What explains the buildup of free oxygen in Earth's atmosphere around two billion years ago?

Back

Photosynthetic organisms became more common on Earth.

Tags

NGSS.HS-LS2-5

Front

What positive impact did the weathering of rocks have on Earth's lifeforms?

Back

The weathering of rocks increased, producing soil and minerals that better supported life.

Tags

NGSS.MS-LS2-3

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Front

How does the development of the Earth's surface relate to the development of life on Earth?

Back

The changing surface of the Earth determined what kinds of organisms could exist.

Tags

NGSS.HS-ESS2-7

Front

Define photosynthesis.

Back

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5

Front

What is the significance of unicellular life in Earth's history?

Back

Unicellular life was crucial for the oxygenation of the atmosphere through photosynthesis.

Front

What role did the oceans play in the early evolution of life on Earth?

Back

The oceans provided a stable environment and protection from harmful radiation.

Front

What is the oxygen cycle?

Back

The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within its three main reservoirs: the atmosphere, the biosphere, and the lithosphere.

Tags

NGSS.HS-LS1-5

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Front

What are the main components of Earth's early atmosphere?

Back

Earth's early atmosphere had very little free oxygen and was primarily composed of nitrogen, carbon dioxide, and other gases.

Tags

NGSS.HS-ESS1-6