The History of Life on Earth

These flashcards cover key concepts from the lecture notes on the history of life on Earth, including the origins of life, major events in evolutionary history, mass extinctions, and adaptive radiations.

What does the fossil record show about major evolutionary changes over time?

It shows macroevolutionary changes such as the emergence of terrestrial vertebrates, the impact of mass extinctions, and the origin of flight in birds.

When is it estimated that Earth formed?

About 4.6 billion years ago.

What was a likely component of Earth's early atmosphere?

It likely contained water vapor and chemicals released by volcanic eruptions.

What are the four predicted steps in the origin of life?

1. Abiotic synthesis of small organic molecules 2. Joining of these small molecules into macromolecules 3. Packaging of molecules into protocells 4. Origin of self-replicating molecules.

What is the defining feature of a eukaryotic cell?

It has a nucleus and other membrane-bound organelles.

When did the Cambrian explosion occur?

The Cambrian explosion occurred approximately 535 to 525 million years ago.

What contributed to the rise and fall of certain groups of organisms?

Speciation and extinction rates within each group.

What defines a mass extinction event?

When 50% or more of marine species become extinct in a short geological timeframe.

What was one consequence of the Oxygen Revolution?

Many prokaryotic groups went extinct due to the accumulation of oxygen in the atmosphere.

What does adaptive radiation refer to in biology?

The rapid evolution of diversely adapted species from a common ancestor when they colonize new environments.