Ethan Kupferberg 1Biology Lecture 2a 8/28/2019Introduction to Evolutionary BiologyHistory of the Earth 1. The formation of the earth2. The cosmic calendar3. Dating and time scales 4. Early life4.6 billion years oldMajor events 1. What happens next: Four major time periods 2. Summary points in the history of time (on Earth)Artificial selection- animal breeding90% of dogs breeds today didn’t exist 100 years agoEarthPhysical changes of the earth support its animals whether it will survive The Cosmic CalendarCOSMOS- Carl SaganPerturbations in the outer rings of the disk became protoplanets Gravity outside the reach of the sun causes matter to condense around protoplanetsIt took 3.8 billion years before life beganHadean eon derived from HadesHadean is the first time period The earth was completely molten, no oceans, no oxygen. Late HadeanWithin 100 million years earth's crust became to breakThe hadean eon ends with the first life: between 4.2 and 3.8 BYA- Fossils - Strata of sedimentary rocks - Radioisotopes dates- Optical/luminescence - Molecular dataEthan Kupferberg 2How we divide time: There are four main time periods in the Earth's history that I want you to know:Precambrian supereon: 4.6BYA - 543MYAPaleozoic era: 543MYA – 250MYAMesozoic era: 250MYA – 65MYACenozoic era: 65MYA – nowThe Hadean eon ends with the first life: between 4.2 and 3.8 BYASingle cell organismsMulticellular life arises late in the Precambrian (1 BYA) And some were clearly capable of movementThe Paleozoic Era: 543MYA – 250MYA The Cambrian explosion: probably not such a big bang Animals were gradually introduced The Paleozoic era sees the first land plants and animalsThe Paleozoic era ends with the Permian extinctionEthan Kupferberg 3The Mesozoic Era 250 MYA – 65 MYA: age of reptiles Mesozoic Era: The first mammals The Mesozoic Era ends with another mass extinction (K-Pg)A Cretaceous- Paleogene (K-Pg) boundary (usually known as “K-T boundary”)The Cenozoic era 65MYA – now: age of the mammals Climate, oxygen and structure of earth are
View Full Document
Unlocking...