Evolution of the Atmosphere Flashcards

All 6 cards in this deck

Where did the gases of the Earth's early atmosphere come from?

Volcanic activity.

Name the gases thought to make up the Earth's early atmosphere.

Mostly carbon dioxide, water vapour, small amounts of other gases, and little or no oxygen.

Why did the amount of water vapour in the atmosphere decrease?

The Earth cooled, so the water vapour condensed and formed the oceans.

Why did the amount of carbon dioxide in the atmosphere decrease as the oceans formed?

Carbon dioxide dissolved in the oceans, and became locked up in sedimentary rocks and fossil fuels.

What caused the percentage of oxygen in the atmosphere to increase from the early atmosphere to today?

Plants (or photosynthetic organisms such as cyanobacteria) produced oxygen by photosynthesis.

What is the chemical test for oxygen, and the positive result?

A glowing splint is placed in the gas; it relights.