OTHER SHIT Flashcards
FREE ME WTF (34 cards)
What is a chemical element?
A chemical element is a substance that consists of only one type of atom, defined by the number of protons in its nucleus. This number is called the atomic number.
What is an isotope?
An isotope of an element is a variant that has the same number of protons but a different number of neutrons, meaning they have the same chemical properties but different atomic masses.
What is radioactive decay and half-life?
Radioactive decay is the process by which unstable atomic nuclei lose energy by emitting radiation. The half-life is the time it takes for half of the atoms in a sample of a radioactive substance to decay.
Parent-Daughter isotope ratios?
Parent isotopes decay into daughter isotopes at a constant rate. By measuring the ratio of parent to daughter isotopes in a sample, we can calculate the time since the rock formed using the radiometric dating technique.
Who was Clair Patterson?
Clair Patterson was a scientist who used uranium-lead (U/Pb) decay to determine the age of the Earth. His work led to the widely accepted estimate of the Earth’s age at approximately 4.6 billion years.
What is the half-life of Uranium-238?
The half-life of Uranium-238 is about 4.468 billion years.
Why did Patterson use meteorites?
Patterson used meteorites because they are considered to have formed around the same time as Earth and have remained unchanged, providing an accurate measure of the Earth’s age.
Oldest known zircon crystals age?
The oldest known zircon crystals are about 4.4 billion years old.
How do geologists calculate the numeric age of a rock?
To calculate the numeric age, geologists measure the ratio of parent to daughter isotopes in a rock sample and apply the known half-life of the parent isotope.
Radiocarbon dating?
Radiocarbon (14C) has a short half-life of about 5,730 years and is used to date organic material up to 50,000 years old. It differs from other radioisotope systems because it decays relatively quickly and is used for dating recent fossils.
Chemical composition of early atmosphere?
Early Earth’s atmosphere likely consisted of methane (CH₄), ammonia (NH₃), water vapor (H₂O), and hydrogen (H₂), with little to no oxygen.
Miller & Urey Experiments?
he Miller-Urey experiment simulated early Earth conditions and showed that amino acids, essential components of life, could form from simple chemicals in the presence of electrical sparks (representing lightning).
Murchison Meteorite?
The Murchison meteorite contained amino acids, suggesting that the building blocks of life might exist in space and could have been delivered to Earth by meteorites.
RNA as original genetic code?
Many scientists believe RNA was the original genetic code because ribozymes, which are RNA molecules, can self-replicate, suggesting that early life could have used RNA for both genetic information storage and catalytic functions.
Where might life have first evolved?
Life may have first evolved in deep-sea hydrothermal vents, where conditions were right for the formation of organic molecules.
What are stromatolites?
Stromatolites are layered structures created by the growth of cyanobacteria. The oldest stromatolites are about 3.5 billion years old.
What is the Great Oxygenation Event (GOE)?
PROTERZOIC EON The Great Oxygenation Event occurred about 2.4 billion years ago when cyanobacteria began producing oxygen through photosynthesis, dramatically changing Earth’s atmosphere and enabling the evolution of more complex life.
When did eukaryotes first appear?
Eukaryotes, organisms with complex cells, first appeared around 1.6 billion years ago.
Cambrian Explosion?
The Cambrian Explosion occurred about 541 million years ago and marks the rapid appearance of most major animal phyla in the fossil record.
What is the Great Unconformity?
The Great Unconformity refers to a significant gap in the geologic record, where layers of rock are missing, possibly due to erosion. It is linked to changes in seawater chemistry, which could have influenced the Cambrian Explosion.
When did the first forests appear?
DEVONIAN
What are gymnosperms?
Gymnosperms are seed-producing plants that include modern conifers like pine trees.
What are amniotes?
mniotes are animals that lay eggs with a protective membrane, such as reptiles, birds, and mammals. This evolutionary innovation allowed vertebrates to colonize land.
What is the Great Dying (Permo-Triassic Extinction)?
The Great Dying occurred about 252 million years ago and was the largest mass extinction in Earth’s history, marking the end of the Paleozoic Era.
