IB Biology: A2.1-Conditions on Prebiotic Earth

Front

What were the surface temperatures on early Earth?

Back

Surface temperatures probably ranged from 75°C to 95°C.

Front

What covered the surface of early Earth?

Back

The surface of the Earth was covered in a single global ocean, with no solid land masses.

Front

What gases were released during volcanic eruptions on early Earth?

Back

Methane, carbon dioxide, and ammonia gases were released.

Front

What formed the majority of Earth's early atmosphere?

Back

Methane, carbon dioxide, and ammonia formed the majority of the Earth’s early atmosphere, along with water vapour (H2O) and higher concentrations of carbon dioxide (CO2) than today.

Front

Why were there only traces of oxygen in early Earth's atmosphere?

Back

Oxygen reacted with other elements such as iron.

Front

What was the state of Earth's inner core on early Earth?

Back

The inner core was much hotter and in a liquid state rather than solid.

Front

How did the liquid core affect Earth's magnetic field?

Back

The increased motion within the liquid core resulted in a smaller protective magnetic field, exposing the planet to higher levels of cosmic and solar radiation.

Front

Why was there no ozone layer on early Earth?

Back

The early Earth’s atmosphere lacked free oxygen, so there was no ozone layer.

Front

What was the effect of the lack of an ozone layer on early Earth?

Back

More solar UV radiation penetrated the Earth’s surface, providing activation energy for chemical reactions.

Front

What role did lightning play on early Earth?

Back

There may have been more lightning, triggering other chemical processes.