Increasing Oxygen in the Atmosphere

What process caused oxygen levels in the atmosphere to increase?

Photosynthesis.

Which early organisms began producing oxygen?

Photosynthetic bacteria, including cyanobacteria.

When did photosynthetic organisms begin producing oxygen?

Billions of years ago, with oxygen production established by approximately 2.7 billion years ago.

What is the word equation for photosynthesis?

Carbon dioxide + water → glucose + oxygen, using light energy.

What is the balanced symbol equation for photosynthesis?

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

How does photosynthesis change atmospheric gas concentrations?

It removes carbon dioxide and releases oxygen.

Why did atmospheric oxygen not immediately accumulate?

Much of the oxygen initially reacted with dissolved iron and other reduced substances.

What is the Great Oxidation Event?

A period when oxygen began accumulating substantially in the Earth's atmosphere.

When did atmospheric oxygen begin increasing significantly?

Approximately 2.4 billion years ago.

How did the evolution of algae affect atmospheric oxygen?

Algae carried out photosynthesis, releasing oxygen.

How did the evolution of plants affect atmospheric oxygen?

Plants increased photosynthetic oxygen production.

Why is photosynthesis essential for maintaining atmospheric oxygen?

It replenishes oxygen consumed by respiration, combustion and other reactions.

What processes remove oxygen from the atmosphere?

Respiration, combustion and oxidation reactions.

Why was increasing oxygen important for the evolution of life?

It enabled widespread aerobic respiration, which releases more energy from glucose than anaerobic respiration.

What is the relationship between photosynthesis and respiration?

Photosynthesis produces oxygen and uses carbon dioxide, while aerobic respiration uses oxygen and releases carbon dioxide.