Earth History Lo 12-21 Flashcards
Radioactive decay and half lives
Radioactive decay is when parts of an isotope decay in half-lives (time it takes for a parent isotope to undergo radioactive decay and become more stable daughter products) until it becomes stable. Radioactivity is the release of energy from a decaying nucleus.
Alpha and beta decay
Alpha Decay is when an atomic nucleus emits an alpha particle, resulting in the transformation of the original nucleus into a different nuclide. However, Beta Decay is characterized by the emission of energetic beta particles, which are electrons or positrons resulting in the transformation of the original nucleus.
Electron capture
Electron Capture is when an electron is captured by a proton in the nucleus.
Radioactive isotope, example, daughter element
A radioactive isotope is an isotope of a chemical element that do radioactivity because of an unstable nuclei. Is from the imbalance of forces within a nucleus and ends with the emissions of particles. For example, uranium-238 (U-238) is a parent element that undergoes radioactive decay to form lead-206 (Pb-206) through a series of decay steps, producing various intermediate daughter isotopes such as thorium-234 and radium-226. The Daughter element is the radioactive isotope that results from the decay of the parent isotope.
Radiocarbon dating
Radiocarbon dating is a method that can accurately determine the age of organic materials.
Earths age and why
The Earth is billions of years old. We know this because scientists have found rocks that date back to then by radiometric dating.
4 eon divisions and key things in bio
Precambrian (longest, 90%) - Single cell organisms dominated, when life was just benign created
Paleozoic Era (second longest) - Marine life dominated, including various fish
Mesozoic Era (second shortest) - Reptiles dominated, including dinosaurs
Cenozoic Era (shortest) - Mammals dominated, including the creation of humans
What marked eons, examples?
Mass extinctions mark the boundaries between eras. The Precambrian Era is separated from the Paleozoic Era because of the Precambrian extinction where most species went abruptly extinct. The Paleozoic Era is separated from the Mesozioc Era because of the Permian-Triassic Extinction which wiped out almost 90% of all marine species as well as major inter vertebral groups. However, after this there was a repopulation and evolution of life. Finally, the Mesozoic Era is separated from the Cenozoic Era when a massive meteor hit the Earth and wiped out all of the dinosaurs, but left some basic things, like seeds and some organisms, which leads to what we see on Earth today.
1st life, 1st crust, 1st plants, 1st photosynthesis, great oxygenation event, 1st vertebrates (fish), 1st amphibians, 1st mammals, 1st humans in order
1st crust, 1st life, 1st photosynthesis, great oxygenation, 1st vertebrates, 1st plants, 1st amphibians, 1st mammals, 1st humans
Know how the geologic time scale was developed.
The geologic time scale is what divides Earth’s history into various intervals based on major geological and biological events and it breaks up the vast expanse of time over which Earth has existed.
Eons - Largest group that is determined by mass extinctions
Eras - Second largest group that is determined by the emergence of new species
Periods - Further separates eras
Epochs - Further separates epochs
Critically assess the influence of greenhouse gas concentrations, including carbon dioxide, methane, and water vapor, on past climate variations, considering natural processes such as volcanic outgassing, as well as anthropogenic factors like deforestation and industrial emissions.
Natural processes such as volcanic outgassing releases gasses into the atmosphere and greenhouse gas concentrations in mass amounts and increases the overall global climate. Deforestation also releases carbon dioxide into the atmosphere and can increase global temperatures. Finally, industrial emissions can release various gasses into the atmosphere that are not good for animals and can hurt, or kill them off.
Analyze the geological evidence for past climate change, including sedimentary records, ice core data, and fossilized flora and fauna, to elucidate patterns and drivers of climate variability over Earth’s history.
For example, the glaciers that we have on Earth are evidence pointing towards the ice ages. Additionally, rock layers made of different types of rocks can help scientists figure out what used to be there and at what time to create the rock layers in the form that they are. Finally, different fossils in rock layers indicate what living in a certain place, and when they were living.
What is the Anthropocene & what defines its boundaries?
The Anthropocene is the most recent geological epoch from the start of significant human impact on Earth to today.
What impacts has the anthropocene made on the environment across Earth’s 4 spheres?
Lithosphere - Wide Scale natural resource extraction
Hydrosphere - Ocean acidification
Biosphere - Habitat destruction
Atmosphere - Carbon dioxide emissions and global warming
