Bio Quiz 3 Study Guide PDF

1. Stromatolites: a. Contain cyanobacteria fossils: Stromatolites are layered structures formed by the activity of cyanobacteria. b. Photosynthetic: Cyanobacteria are photosynthetic organisms, meaning they use sunlight to produce energy. c. Tough, multilayered cell...

1. Stromatolites: a. Contain cyanobacteria fossils: Stromatolites are layered structures formed by the activity of cyanobacteria. b. Photosynthetic: Cyanobacteria are photosynthetic organisms, meaning they use sunlight to produce energy. c. Tough, multilayered cell walls: These walls aid in the preservation and fossilization of cyanobacteria, contributing to the formation of stromatolites. d. Oxygen contribution: Cyanobacteria played a key role in raising atmospheric oxygen levels during Earth\'s early history. e. Geologic Time Scale: Precambrian (4.5 billion years ago -- 550 million years ago): Encompasses the Hadean, Archean, and Proterozoic Eons, representing the majority of Earth\'s history before complex life emerged. f. Phanerozoic Eon: Paleozoic Era (550 mya -- 250 mya): Started with the Cambrian Explosion, leading to a rapid increase in complex life forms. g. Major periods: Cambrian, Ordovician, Devonian, Carboniferous, and Permian. Ended with the Permian Extinction, which caused the loss of 95% of species. h. Mesozoic Era (250 mya -- 65 mya): Known for the dominance of dinosaurs and includes the Triassic, Jurassic, and Cretaceous periods. Ended with the K-T Extinction, resulting in the loss of 80% of species, including the dinosaurs. i. Cenozoic Era (65 mya -- present): Periods include Paleogene, Neogene, and Quaternary. This era is characterized by the rise of mammals and the development of human life. 2. Iridium: j. Iridium bands: Found at certain extinction event boundaries, notably at the K-T boundary, marking the mass extinction that wiped out the dinosaurs. k. Rare metal: Iridium is one of the least abundant metals on Earth but is common in meteorites. l. Properties: Highly dense, resistant to erosion, and capable of withstanding extreme temperatures (up to 2,000°C). m. Applications: Used in satellites, spark plugs, and decorative items due to its durability and rarity.