BIOLOGY 101 Chapter Notes - Chapter 25: Radiometric Dating, Montmorillonite, Stromatolite
Document Summary
Macroevolution: the broad pattern of evolution above the species level: ex: emergence of terrestrial vertebrates, impact of mass extinction. Four main stages of the earths creation: 1. The abiotic (nonliving) synthesis of small organic molecules, such as amino acids: 2. The joining of these small molecules into macromolecules, such as proteins and nucleic acids: 3. Protocells: droplets with membranes that maintained an internal chemistry different from that of their surroundings: 4. The origin of self-replicating molecules that eventually made inheritance possible. Earth formed about 4. 6 billion years ago. Miller-urey-type experiments demonstrate that the abiotic synthesis of organic molecules is possible under various assumptions of the early atmosphere. By dripping solutions of amino acid or rna molecules onto hot sand, clay, or rock, researchers have produced polymers of these molecules: the polymers formed spontaneously without the help of enzymes or ribosomes. It is possible that polymers ay have acted as weak catalyst for many chemical reactions on early earth.
