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.
3 types of rocks
Igneous
Sedimentary
Metamorphic
Igneous rocks
All types of rocks can be changed into igneous rock by melting, cooling and crystalizing of any rock.
How Sedimentary rocks are formed
Formed when rocks are weathered and eroded, sediments compact and cement solid rock.
3 types of Sedimentary rocks
Organic: Fossilized remains of plants or animals.
Clastic: Fragments of other rock are compacted together.
Chemical: Sediments are “glued” together by dissolved minerals.
Texture is determined by the size of the particle of sediment.
How Metamorphic rocks are formed
Formed when existing rock is changed into new rock by the heating of the rock and pressure from other rocks around it.
2 types of Metamorphic rocks
Foliated: crystals aligned in layers
Non-foliated: Crystals arranged in random manner
All types of rocks
can be changed into metamorphic rock by heat and pressure.
Prokaryotes
microscpic single celled organisms that has neither a distinct nucleus with a membrane nor specialized organelles (unicellular), and the protein is naked.
Eukaryotes
Any organism whose cells contain a nucleus and other membrane enclosed organelles.
Cells: mitochondria - power plants of the cells (produces chemical energy)
Endosymbiotic Theory States
some of the organelles in eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are the same size as prokaryotic cells and divide by binary fission. Mitochondria and chloroplasts have their own DNA which is circular, not linear.
Law of Superposition
Use to determine the relative ages of rock layers.
Layers of rock are laid down one on top of another.
The oldest rock strata will be on the bottom and the youngest at the top.
Sedimentary rock cycle
WEATHERING (rain beating on rocks) causes EROSION (bits of rocks, sediments, fall off). DEPOSITION (sediments fall into body of water) causes sediments to layer horizontally and be COMPRESSED by gravity + water and CEMENTATION occurs (they squish a lot and become rock.
Living Fossils
Stromatolies, ‘strange fish Coelacanth: an animal or plant that has remained almost unchanged from earlier geologic times and whose close relatives are usually all extinct. (not an actual fossil)
Transitional Fossils
Fishapod: The linking animal between fish and tetrapods (prequel to amphibians)
The transitional fossils are fossils that show intermediary links between groups of organisms. It provides a link between the past and present species
The Great Unconformity
Occasionally big holes occur in rock formations where rocks from 200 mya are right below rocks from 50 mya. There is a huge 150 mya gap caused by the influence of wind and water as they move particles around and delete gaps.
What is the significance of Prokaryotes and Eukaryotes?
Prokaryotes were the first form of life. Scientists believe that eukaryotes evolved from prokaryotes around 2.7 billion years ago. The primary distinction between these two types of organisms is that eukaryotic cells have a membrane-bound nucleus and prokaryotic cells do not.
What was Tiktaalik and why is it important?
Tiktaalik provides clues about a key transition in the history of life. Now extinct, this organism was a close relative of one our own ancestors — the first vertebrate to evolve four limbs and crawl out onto dry land.
A key transitional fossil between fish in water and tetrapods on land.
Tiktaalik roseae, an extinct fishlike aquatic animal that lived about 380–385 million years ago (during the earliest late Devonian Period)
Coelecanth (lobe-finned fish)
Coelacanths were thought to be the ancestors of the tetrapods (land-living animals, including humans). It is now believed that Lungfishes are the closest living relative of tetrapods.
Lobe finned fish
Discovered in 1938 by Marjorie Courtonay Latimer
Thought to have been extinct
The link between fish an amphibians.
Stromatolites
A stromatolite is a layered rock that was left behind by a colony of bacteria – specifically, cyanobacteria. Cyanobacteria are microscopic, single-celled organisms that can photosynthesize. Cyanobacteria live in shallow water and are sometimes referred to as blue-green algae.
How stromatolites contributed to life today.
What’s more, Stromatolites are the reason why we’re alive today! Before cyanobacteria the air was only 1% oxygen. Then, for 2 billion years, photosynthesising Stromatolites pumped oxygen into the oceans (like underwater trees, before trees existed).
Earth Timeline
4.6 billion years ago: Earth formed planetary nebular.
2.2 billion years ago
542 million years ago: “Cambrian Explosion” (Fish - Amphibians - Reptiles - Dinosaurs - Dinosaurs - Mammals - Birds)
Sedimentary - Metamorphic
Metamorphism - Heat and/or pressure.
Sediments - Sedimentary rock
Deposition and burial - Compaction and/or Cementaion
Metamorphic rock - magma
melting
Magma - Ingenous rock
Solidification
Ingenous rock - Magma
Melting
Igneous rocks - sediments
(uplift) - weathering and erosion
Intrusive Igneous rock
Magma cools slowly beneath earths surface
larger crystals
coarse graned (texture)
Extrusive igneous rock
Lava cools quickly on the surface
Smaller crystals
Fine grained (texture)
Igneous is formed
when magma or lava cools and hardens (solidifies)
Tetrapod
The Four-Legged Vertebrates
Air breathing lungs
amphibians, birds, reptiles and mammals
appeared in fossil record 375 million years ago
Transitional Fossil between fish and tetrapods
tiktalik - had fins with thin ray bones, scales, and gills like most fish. However, it also had the sturdy wrist bones, neck, shoulders, and thick ribs of a four-legged vertebrate.
