BIOL 110 Chapter 25: CH 25 Study Guide
Document Summary
Chapter 25 study guide: past organisms were very different from those now alive. The fossil record shows macroevolutionary changes over large time scales, for example: Earth formed about 4. 6 billion years ago, along with the rest of the solar system: bombardment of earth by rocks and ice likely vaporized water and prevented seas from forming before 4. 2 to 3. 9 billion years ago. Earth"s earl(cid:455) at(cid:373)osphere likel(cid:455) (cid:272)o(cid:374)tai(cid:374)ed (cid:449)ater (cid:448)apor a(cid:374)d (cid:272)he(cid:373)i(cid:272)als released (cid:271)(cid:455) (cid:448)ol(cid:272)a(cid:374)i(cid:272) eruptions (nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide) In the 1920s, a. i. oparin and j. B. s. haldane hypothesized that the early atmosphere was a reducing environment. Abiotic synthesis of macromolecules: rna monomers have been produced spontaneously from simple molecules. Small organic molecules polymerize when they are concentrated on hot sand, clay, or rock. Protocells: replication and metabolism are key properties of life and may have appeared together, protocells may have been fluid-filled vesicles with a membrane-like structure.
