Scienc Flashcards
How and when did earth come to be?
4.6 billion years ago. Formed from a supernova (giant star explosion) which left behind a giant cloud of elements which formed all the planets.
Know the names and basic facts about the four eons
Hadean - No life/hell
Archean - First life! Solid rock, oceans formed
Proterozoic - Cyanobacteria started producing Oz which allowed more life to form and filled the atmo with air
Phanerozoic - Our current eon! All big life & oxygen in atmo. We lump the first 3 eons into “Precambrian Time”
When are we?
Phanerozoic eon
Cenozoic era
Quarterternary Period
Holocene epoch
What is the major difference between the early and late pre-Cambrian eras?
In the beginning no life, just hell like, next solid, rock, oceans, and 1st life; finally, next was cyanobacteria which began producing oxygen which allowed more life to form and then
Which time period has taken up the most of Earth’s history?
Precambrian time: 88.6% of earth’s history
What is the major difference between the types of life in the late pre-Cambrian era and every era following?
Precambrianlife single selled, then cambrian explosion so life everwhere! Cyanobacteria was late precambrian, and then every era following = life as we know it. The produced oxygen from the cynobacteria helped more life form.
When (eon, era, period) did humans first evolve?
Humans evolved in the Cenozoic era, phanerazoic eon and quaternary period
What marked the end of the Mesozoic era?
Massive meteor that wiped out all of the dinosaurs, and 80% of life
What is the Cambrian explosion?
Start of the cambrian period, and the phanerozoic eon. Gigantic inceease in life! Now, not only single celled organisms but multi celled organisms. Happened because of the oxygen. Not actual explosion.
What is relative dating and relative age?
Relative Dating: Comparing between rocks to see which are older + younger
Relative Age: The relative age of a rock is its age compared to the age of other rocks
What is absolute dating and absolute age?
Absolute dating finds out the actual age of rocks/fossils by using radioactive isotopes and their half-lines to determine the age.
Absolute age: The Absolute age of a rock is the number of years that passed since the rock formed. You get the absolute age by doing the half lives math /radiometric dating.
What is the law of superposition?
Younger rocks are above older rocks but this is not always true, because erosion, earthquakes, and intrusion could alter the placement of the rocks. Intrusion is when lava gets entered between the rock layers and becomes the newest part.
What is radioactive dating?
Uses radioactive dating to find the age
bndex fossils
This helps geologists match & date rock layers
What is the difference between the Permian-Triassic Extinction and the Extinction of
Dinosaurs at the end of the Mesozoic Era?
Probably caused by super volcanoes ended permian period also much bigger. Dinasousrs caused by asteroids
What is the major difference between the early and late pre-Cambrian eras?
The biggest difference between these two times is the early pre-Cambrian had little to no life/only single cell organisms while late precambrian had oceans formed and multiple cell organisms.
Age of Mammals
In Cenozoic Era opposite of age of reptiles/dessert area
Continents Form
Hadeon Eon
Oxygen Rising
Proterazoic Eon
First life
Archean Eon
First Trilobites
Cambrian Period
First Dinosaurs
Triassic Period
Age of Mammals
Cenozoic Era
What is an extinction event/mass extinction?
Huge asteroid/Super volcanoes. A lot of species all around the world go extinct.
