Chapter 13: Microbial Evolution and Genome Dynamics

Exam 3

About how old is Earth?

4.5 billion years old

About how long ago did liquid water first appear?

4.3 billion years ago

First evidence for microbial found in rocks are about how old?

3.86 billion years old

Why type of atmosphere did early earth have?

anoxic and much hotter than it is today

The first biochemical compounds were made by?

abiotic systems

What is the surface origin hypothesis state?

• primordial soup rich in organic and inorganic compounds

• environment was too hostile

What does the subsurface origin hypothesis state?

• life may have originated at hypothermal springs on the ocean floor

• conditions were more stable

• there was a steady and abundant supply of energy in reduced inorganics

• Geochemistry can support abiotic production of molecules required for life

• Mineral structures may have produced compartments for conserving energy