Origin of Life review

LUCA

All living creatures are composed of organic
matter ("organic" in the sense that it is made of carbon), and the origins of life on Earth is really a question of where did organic molecules come from?

The prevailing theory is that all life on Earth originated from a last universal common ancestor (LUCA).

Extraterrestrial Life

The theory that life originated from an extraterrestrial

source is called panspermia.

A convenient theory that argues life on earth originated from a meteorite, comet, or other space rock landing and bringing life to Earth.

Spontaneous Generation and Biogenesis

From the time of Aristotle, people believed that organisms could arise from non-living matter. Like bugs appearing on rotting meat.

Louis Pasteur disproved this theory, and started the theory of biogenesis-life comes from life.

Charles Darwin shared his controversial idea that all living things evolved from a
last universal common ancestor.

Later, Alexander Oparin introduced this idea as primordial soup.

He suggested that the non-living
chemicals in the ocean and atmosphere could react to form more complex
compounds to build life

Primordial Soup

Miller-Urey Experiment

One of the most famous experiments on the origin of life. The simulated early earth’s atmosphere with gases like: methane, ammonia, hydrogen, and water vapor. They used a spark to simulate lightning. And they condensed the water vapor to recreate “precipitation.”

In this simulation-they created the building blocks of life-amino acids.

Eukaryotic cells formed from a endosymbiotic relationship with prokaryotic cells.

Evidence: Both the mitochondria and chloroplast have similar features to free-living bacteria.

1.

They both contain DNA

2.

They replicate and divide in a similar way to bacteria.

Endosymbiotic Theory