The document summarizes theories on the origin of life. It notes that people originally believed in spontaneous generation, where life emerged from non-living matter, but this view was disproven. The current leading theory is that under conditions simulating early Earth, like in the Miller-Urey experiment of 1953, amino acids and DNA components could form. Over millions of years, these molecules may have combined into microspheres with membranes that eventually evolved into the first living cells.

1. Notes: Origin of Life (pg 2)

2. Notes: Origin of Life (pg 2)
• People used to believe that life arose through
Spontaneous Generation (life emerging from
non-living matter)

3. Notes: Origin of Life (pg 2)
• People used to believe that life arose through
Spontaneous Generation (life emerging from
non-living matter)
• Example: Belief that rotting meat turned into
maggots

4. Notes: Origin of Life (pg 2)
• People used to believe that life arose through
Spontaneous Generation (life emerging from
non-living matter)
• Example: Belief that rotting meat turned into
maggots
• Spontaneous generation was disproved by
Francesco Redi (1668) and Louis Pasteur
(1850s)

6. Current theory on the origin of life
• Miller and Urey experiment (1953): made a
simulation of Earth’s early atmosphere
(methane, ammonia, hydrogen), added water
and electric shocks (to simulate lightning).
After several weeks, amino acids had formed.

7. Current theory on the origin of life
• Miller and Urey experiment (1953): made a
simulation of Earth’s early atmosphere
(methane, ammonia, hydrogen), added water
and electric shocks (to simulate lightning).
After several weeks, amino acids had formed.
• More recent experiments have produced
bases found in DNA

9. Current theory on the origin of life
• Miller and Urey experiment (1953): made a
simulation of Earth’s early atmosphere
(methane, ammonia, hydrogen), added water
and electric shocks (to simulate lightning). After
several weeks, amino acids had formed.
• More recent experiments have produced bases
found in DNA
• Under certain conditions, large organic
molecules form microspheres, which have
selectively permeable membranes. Over millions
of years, these microspheres may have evolved
into cells.