The Impact of Cyanobacteria on Earth's History

Cyanobacteria, simple single-celled organisms, played a crucial role in Earth's history by introducing oxygen into the atmosphere through photosynthesis. This led to the Great Oxygenation Event, causing a mass extinction and the Huronian Glaciation. Over time, life adapted to the oxygen-rich environment, leading to the evolution of complex organisms. Cyanobacteria also contributed to the development of plant cells through endosymbiosis, becoming chloroplasts. Today, they continue to influence Earth's ecosystems by producing oxygen and fixing nitrogen.

What organisms were responsible for the first mass extinction on Earth?

• Dinosaurs

• Cyanobacteria

• Mammals

• Anaerobic microbes

What was Earth's atmosphere composed of before the advent of cyanobacteria?

• Mostly oxygen and nitrogen

• Mostly nitrogen, carbon dioxide, and methane

• Mostly hydrogen and helium

• Mostly oxygen and carbon dioxide

What process allowed cyanobacteria to produce oxygen?

• Respiration

• Chemosynthesis

• Photosynthesis

• Fermentation

What advantage did photosynthesis give to cyanobacteria?

• Ability to move to different environments

• Ability to survive without water

• Ability to produce their own energy from sunlight

• Resistance to high temperatures

What was the primary consequence of cyanobacteria's photosynthesis?

• Increase in atmospheric carbon dioxide

• Decrease in atmospheric nitrogen

• Increase in atmospheric oxygen

• Decrease in atmospheric oxygen

What event is known for causing a mass extinction due to oxygen increase?

• Great Oxygenation Event

• Cambrian Explosion

• Permian-Triassic Extinction Event

• Cretaceous-Paleogene Extinction Event

What did the extra oxygen in the atmosphere react with to cause cooling?

• Hydrogen

• Nitrogen

• Methane

• Carbon dioxide

What was a significant effect of the Great Oxygenation Event?

• The formation of the ozone layer

• The start of the Huronian Glaciation

• The diversification of aquatic life

• The decrease of carbon dioxide in the atmosphere

What was the long-term outcome of the oxygen increase caused by cyanobacteria?

• Permanent ice age conditions

• Extinction of all life forms

• Development of aerobic organisms

• Decrease in Earth's overall temperature

How did cyanobacteria contribute to the evolution of plant cells?

• By becoming the first plants

• Through mutation into plant cells

• By being engulfed in a process called endosymbiosis

• By pollinating early plants