The History of Life Flashcards
Earth was a molten body when it formed…
4.6 billion years ago.
Fossil is…
Any preserved evidence an organism.
The surface was rich in…
Lighter elements
There was no……… In earths atmosphere
Oxygen
Trace fossil is…
Any indirect evidence left by an organism. Footprints, feces.
Molds and casts are…
An impression of an organism. Cast… Mold filled with sediment.
Replacement is…
The original material of an organism is replaced with mineral crystals that can leave detailed replicas of hard or soft parts.
Petrified or permineralized is…
Empty pore spaces are filled in by minerals, such as petrified wood.
Amber is…
Preserved tree sap traps an entire organism. It hardens into Amber and preserves it.
Original material is…
Mummification our freezing preserves original organisms.
Fossils are formed in..
Sedimentary rock
Paleontologist studies…
Fossils
Relative Dating is…
A method used to determine the age of rocks by comparing them with those in other layer]s.
Law of Superposition is…
A law that states that younger layers of rocks are positioned on top of the older ones.
Radiometric dating is…
Use the decay of radioactive isotopes to measure the age of a rock.
Half-life is…
The medium time.
Radiometric dating is used only on…
Ingenious and Metamorphic rocks.
Geologic Time Scale is…
A record of Earth’s history.
Epochs last…
Several million years. Are the smallest unit of geologic time.
Periods last…
Tens of millions of years. Consist of two or more epochs.
Eras last…
Hundreds of millions of years. Two or more periods.
Eons last…
Billions of years. Longest unit of geologic time.
Precambrian Era
Cells appear.
Paleozoic Era
Cambrian explosion. First animals appear. Insects appeared.
Mesozoic Era
Periods: Triassic, Jurassic and Cretaceous Birds appear, Dinosaurs scatter Mammals appear Mass extinction, K-T Boundary Meteorite
Cenozoic
Mammals scatter Primates start to appear. Ice ages occur. Humans appear.
Spontaneous Generation
The idea that life arises from non life. Francesco Redi, tested the idea and proved wrong.
Theory of Biogenesis
States that only living organisms can produce other living organisms. Louis Pasteur experimented this idea with flasks and chicken broth.
Miller-Urey Experiment
People thought that life came from the atmosphere by lightning. They tested this and proved it was right. Organic Compounds like AMINO ACIDS were produced.
Proteins
Were made by amino acids sticking to small clay particles. This prevented unstable proteins.
Endosymbiotic Theory
Prokaryotes lived inside eukaryotes and transformed overtime to the mitochondria and the chloroplast.
Young Earth was…
Hotter than it is today.
Primordial Soup
Lightning and sunlight make organic compounds.
Organic molecules could have been synthesized on the…
Atmosphere and ocean
Order of Geologic Time
Paleozoic–Mesozoic–Cenozoic
