Chapter 20

the process by which life adjusts itself to changing environments

• the long carbon-chain molevule that records information to govern the biological activity of the organism.
• DNA carries the genetic data passed to offspring

complex molecule composed of amino acid units

carbon-chain molecule that is the building block of protein

special protein that controls processes in an organism

a body within a living cell that contains genetic information responsible for the deremination and transmission of hereditary traits

an experiment that reproduced the conditions under which life began on Earth and manufactured amino acids and other organic compounds

a sudden increase in the complexity of life on Earth that signaled the beginning of the Cambrian period

• a region around a star within which a planet can have temperatures that permit the existence of liquid water
• also known as the life zone

a message that is designed to be easily decoded

an exploratory science that seeks evidence of life in the universe by looking for some signatures of its tecnhology

the equation that estimates the total number of communicaive civilizations in our galaxy