U4L1E3: History of Life on Earth

Front

What did cyanobacteria release that changed the early Earth's atmosphere?

Back

Oxygen

Front

What does the Cambrian Explosion refer to?

Back

The sudden appearance of many different types of lifeforms in the fossil record.

Front

What is a mass extinction?

Back

When multiple species from all over the earth suddenly go extinct.

Front

What provides evidence about the history of life on Earth?

Back

Fossil record.

Front

What do younger rock layers in the fossil record show?

Back

Both a greater variety of life and more complex organisms.

Front

What are cyanobacteria?

Back

Photosynthetic bacteria that played a crucial role in oxygenating the Earth's atmosphere.

Front

What is the significance of the fossil record?

Back

It shows how organisms have changed through time and provides evidence of past life.

Front

What is an index fossil?

Back

A fossil that is used to define and identify a particular time period in the geologic time scale.

Front

What is the geologic time scale?

Back

A system of chronological dating that relates geological strata to time.

Front

What is the role of mass extinctions in evolution?

Back

They can lead to the rapid evolution of new species by opening up ecological niches.