Environmental Science Test on Geology Grade 9 Flashcards
Hadean Eon
(of the underworld)
4.6-4.0 billion years ago: Jan 1 - Feb 17
Hades - Ancient Greek God of the Underworld.
Archaen Eon
(Ancient Beginning)
4.0-2.5 billion years ago: Feb 18 - June 16
Single-celled: prokaryotes (no membrane bound organelles - Bacteria and Archaea)
- the formation of the oxygen layer
Stromatolites (Evidence 1 of Archean Eon
Living Fossils - living organisms and has not changed much from ancient times.
Banded Iron Formations - BIF (Evidence 2)
A sedimentary rock layer
Tells us period that were oxygen rich and oxygen poor.
The darker the color the more oxidized the rock is.
Each layer several is hundreds of millions years.
Proterozoic Eon
(Early Life)
2.5 billion - 542 million years ago: June 17 - Nov 18
Endosymbiotic Theory
1) Bacteria separate from Archaea
2) Bacteria engulfs archaea
3) Becomes eukaryotic cell
Phanerozoic Eon
(Visible Life)
542 million years ago - Today: Nov 19 - Dec 31
“Cambrian Explosion” (Biodiversity)
Early Phanerozoic
Ordovician - Silurian Mass Extinction
445-440 million years ago
86% all species were lost because all the plants.
-hypoxia, too much oxygen everything suffocated and died.
- after extinction we get plants on land (before everything was in water)
Devonian Mass Extinction
375-359 Million years ago: Dec 4
Too much oxygen possibly from explansion of plants, two theories, but plants did it, or too much CO2 from volcanism.
Permian Mass Extinction
(The great dying)
252 million years ago: Dec 12
Killed 96% of all life because too much volcanic eruption, the atmosphere of earth was inhabitable, lower sea levels and warming of earth’s climate.
Triassic Mass Extinction
198 million years ago: Dec 17
80% of all life was killed due to volcanism, too much C02, ocean acidification.
Cretaceous Mass Extinction
66 million years ago: Dec 27
One asteroid of multiple killed 60% of life on earth (asteroid causes a chain reaction, like tsunamis)
TriasAge of Mammals
66 million years ago - present : Dec 28-31
Old Theory of Geology
Catastrophism (1600s)
Geological events happen suddenly
New Theory of Geology
Uniformitarianism (By James Hutton)
Geological events tend to happen slowly over long periods of time.
Transitional Fossils
Fish, amphibians (transitional), reptiles, dinosaurs, mammals, bird
Rocks are
Solid Mixture of minerals
May be organic
Minerals are
Naturally formed of elements or compounds.
Inorganic solid.
Have crystals.
Not made of rocks .
Has definite chemical makeup.
Rocks are classified by
How they are formed
Each type of rock is defined by:
Composition: what minerals the rock is made of.
Texture: sizes, shapes and positions of grains in the rocks.
Minerals are classified by
chemical composition
Compositions of rocks
is determined by the kind of minerals and the amount of minerals that make it up.