Earth's Early Atmosphere

Study for semester exams.

Early atmosphere

Earth’s original atmosphere with no oxygen and many gases from volcanoes

Organic compounds

Carbon-based molecules essential for life.

Chemical evolution

The idea that life arose from nonliving chemical substances

Miller-Urey Experiment

Experiment showing that organic molecules can form under early Earth conditions.

Protocell

A simple, membrane-bound structure that showed characteristics of life.

RNA World Hypothesis

Idea that RNA existed before DNA and proteins

Universal Genetic Code

The fact that almost all organisms use the same genetic code to make proteins

Nucleotide

building blocks of RNA and DNA

Codon

three RNA bases that code for one amino acid

Common Ancestor

earliest life form shared by all organisms