Origins of Life I: Early Ideas and Experiments

The key to knowing how life appeared is knowing when life appeared.

• a.true
• b.false

Why did it take millions of years for life to appear on Earth after the planet had formed?

• a.The planet had cooled down enough to sustain life.
• b.The planet had warmed up enough to sustain life.
• c.Life on Earth could begin only when seedlings arrived on our planet from other worlds.
• d.It took millions of years for RNA to replace DNA.

Charles Darwin the first person to propose the idea of spontaneous generation.

• a.true
• b.false

More than 2,000 years ago, Anaximander decided that humans descended from fish because

• a.fish offspring are born ready to survive on their own.
• b.fish skeletons were strikingly similar to human skeletons.
• c.the way that fish mothers care for their young is similar to how human parents care for their young.
• d.this was a natural progression since it was already demonstrated that small living organisms came from the nonliving mud at the bottom of the sea.

Who disproved the idea of spontaneous generation was once and for all?

• a.Aristotle
• b.John Needham
• c.Lazzaro Spallanzani
• d.Louis Pasteur

What was the paradox between the work of Darwin and that of Pasteur?

• a.Darwin’s work ultimately disproved Pasteur’s ideas.
• b.Pasteur’s work disproved Darwin’s ideas about natural selection.
• c.Pasteur’s work posed a challenge to ideas about how life ultimately began.
• d.Pasteur’s findings were incompatible with the evolution of species.

The term abiogenesis

• a.means the same thing as spontaneous generation.
• b.describes the emergence of life forms from nonliving chemical systems.
• c.is another name for natural selection.
• d.describes the emergence of small organisms from mud.

The first living cells on Earth most likely

• a.were heterotrophs.
• b.were autotrophs.
• c.were capable of photosynthesis
• d.were dependent on the oxygen in the atmosphere.

Which is NOT a step in the emergence of life proposed in the Oparin-Haldane hypothesis?

• a.Lighting sparked chemical reactions among simple organic compounds in the primordial soup.
• b.Molecules began copying themselves, using other molecules in the primordial soup as building blocks.
• c.Photosynthesis supplied the oxygen necessary for self-copying molecules to thrive and form membranes.
• d.Self-copying molecules ate the primordial soup.

Stanley Miller and Harold Urey recreated Earth’s early atmosphere in a test tube. Then they bombarded the chemical mixture with ultraviolet light and simulated lightning. What were the results?

• a.Cell membranes had formed.
• b.Amino acids and other biological molecules were created.
• c.RNA molecules formed.
• d.DNA molecules emerged.