Ch 25 The History of Life on Earth
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| the pattern of evolution over large time scales | ||
| abiotic synthesis of small organic molecules, ex. amino acids, nucleotides | ||
| joining of monomers into polymers, ex. proteins, nucleic acids | ||
| packaging of molecules into membrane-bound droplets ex. liposomes and protobionts | ||
| origin of self-replicating molecules which eventually made inheritance possible | ||
| water vapor, nitrogen and nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen sulfide | ||
| water vapor condensed to form oceans, hydrogen went out into space | ||
| thought atmosphere was reducing (add electrons and hydrogens onto molecules), so organic molecules could be synthesized. E for reactions from lighting and UV light | ||
| tested Oparin hypothesis by recreating early atmospheric conditions in lab, made amino acids and other organic compounds | ||
| early atmosphere didn't have enough methane or ammonia to be reducing (Miller test does not work without these) | ||
| probably small areas that contained the right mix of chemicals to form organic compounds, by volcanoes, deep sea vents | ||
| collections of abiotically produced molecules surrounded by a membrane-like structure, can form spontaneously | ||
| simpler than DNA, can take various 3-d shapes, can act as ribozyme to catalyze reactions, more copying errors and variation, can self-replicate, can be acted on by natural selection | ||
| order of fossils in the rock strata | ||
| based on the decay of radioactive isotopes, when a radioactive parent isotope decays to a daughter isotope at a constant rate | ||
| time required for 50% of the parent isotope to decay | ||
| measurements of magnetism between rock layers, reversals of north and south magnetic poles over time can be matched with corresponding patterns in the rock | ||
| distinct age in the history of Earth and its life | ||
| era, period, epoch | ||
| 4.6 bya-543mya | ||
| first life on earth- stromatolites, cyanobacteria, prokaryotes | ||
| layered rocks that form when certain prokaryotes bind thin films of sediment together | ||
| oxygen revolution | ||
| oxygen produced by photosynthesizing prokaryotes, doomed anaerobic organisms, cell respiration and chemiosmosis evolved, ozone layer began to protect organisms from UV light | ||
| oxygen bonded with iron in the oceans and formed bands of iron oxides in the rocks | ||
| first eukaryots | ||
| mitochondria and chloroplasts independently living prokaryotes, ingested by other prokaryotes and lived inside them | ||
| inner membranes of both have enzymes and transport systems like proks, both replicate by binary fission, both have a singular DNA piece without a lot of histones, similar size, sequences, and antibiotic sensitivity, ribosomes similar to proks | ||
| first multicellular organisms, probably started as colonies | ||
| severe ice ages between 750 and 580 mya sent most life to deep sea vents, hot springs, or near equator | ||
| mitochondria evolved before plastids through a sequence of endosymbiotic events | ||
| 543 mya-245 mya | ||
| ferns and arthropods (insects, spiders) | ||
| 535-525 mya, huge adaptive radiation: hard shells, predator/prey, claws, spines, body armor | ||
| 500 mya, colonization of land by plants, fungi, and animals | ||
| adaptions that allowed reproduction on land and prevented dehydration | ||
| plates of the earth's crust move over time in a process called continental drift | ||
| supercontinent, caused Permian extinction | ||
| 245 mya, occurred in 5 million to a few thousand years. 96% of marine life died | ||
| enormous volcanic eruptions in Siberia, too much lava and ash, CO2 heated planet and oxygen deficit | ||
| 245 mya-65mya | ||
| gymnosperms and reptiles (dinosaurs) | ||
| 65 mya, extinction of dinosaurs, cause a large asteroid or comet | ||
| 65 mya-present time | ||
| angiosperms and mammals | ||
| 65 mya, adaptive radiation of mammals | ||
| 195000ya, modern humans appear | ||
| more than 1000 species extinct in 400 years- 10000 times typical rate | ||
| period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities | ||
| subduction of oceanic plate=volcano, mountain building, slide past=earthquakes, plate separate=deep sea, new earth surface | ||
| ocean basins got deeper, se levels lowered, severe continental climate, less coastline, alters ocean currents, promotes speciation | ||
| it is forever, takes 5-10 million years to recover, lead to adaptive radiation | ||
| mammals after dinos, cambrian explosion after predators formed, photosynthesis, colonization of land after photo., regional adaptations | ||
| changes in developmental genes determines shape of organism | ||
| retain juvenile body feature in the adult | ||
| master regulatory genes | ||
| changes in hox genes, duplication of genes, changes in gene regulation |