Unit 7: Topic 13 - Origin of Life on Earth Flashcards
Approximately when was Earth formed, when was its environment hostile until, and when was its earliest fossil evidence?
The approximate date of the formation of Earth is 4.6 billion years ago. Earth’s environment was hostile until 3.9 billion years ago, and Earth’s earliest fossil evidence dated back 3.5 billion years.
What did inorganic precursors allow for regarding the origin of life?
Inorganic precursors allowed organic molecules to be synthesized in primitive Earth’s environment. The primitive environment contained free energy and a general absence of atmospheric oxygen.
What is the meteorite theory regarding the origin of life?
Organic molecules were transported to Earth by a meteorite. This is supported by evidence showing organic molecules can be produced in space and on discovered meteorites on Earth.
What was Miller and Urey’s Experiment, and what resulted from it?
The experiment tested Oparin and Hadley’s hypothesis that organic molecules could be synthesized in the atmosphere. Building blocks for complex molecules and covalent bonds were formed, allowing monomers to join to create polymers. Some building block polymers included amino acids, lipids, and carbohydrates. The experiment took place in a closed system containing heated water, sparks of electricity (to replace free energy), and early atmospheric gasses. Click here
What is the metabolism-first hypothesis?
This hypothesis states metabolic reactions were the first simple life on earth and came before any genetic material. One plausible scenario involves undersea hydrothermal vents providing the availability of chemical precursors which allowed for simple molecules to undergo metabolic reactions. The reactions would be self-sustaining and constant, hypothetically leading to the eventual formation of more complex molecules.
What is the RNA World Hypothesis?
RNA could have been the earliest genetic material instead of DNA. Catalytic RNA or ribozymes could self-replicate and undergo evolution.
