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Prehistoric Life Mid
Midterm for Prehistoric Life (look at the geologic scale)
| Question | Answer |
|---|---|
| How many years has life existed on Earth | 3.5 Billion years |
| when did the sun and planets form from a solar nebula | 4.54 Billion years ago |
| how was the moon created and what happened | 4.5 billion years ago Thea (a large object) collides with Earth, getting absorbed and shoots out other material that forms the moon. It also is theorized this jumpstarted life on Earth through chemical reactions. |
| Why is there no water in rocks on the moon if its from Earth? | The impact with Thea was so extreme that it vaporized all the water out as it was ejected to where it orbits now. |
| 4.54 Billion Ya to 154 million Ya is what time period and what happened. | Precambrian time period, Earth forms a Biosphere, the first continents form, shallow oceans which could support early life also form. |
| How did the atmosphere evolve to no longer be toxic to us? | Early bacteria and ocean plants in shallow oceans absorbed these toxic chemicals and changed the atmosphere to be more oxygen rich like how we see today. |
| What started occurring after Thea struck Earth | differentiation, or seperation of elements began to happen based on density. Denser elements began sinking towards the core while lighter elements stayed near the top. |
| Layers of Earth | Solid inner core, liquid outer core, Largest layer the mantle is both solid and liquid, and crust is the upper layer of Earth. |
| How do we measure what the composition of the Earth is if we havent dug even into the mantle yet? | We measure earthquakes and how they bounce and react inside the Earth, and where the siesmic waves come up and how fast they do help paint a picture of what its like in there. |
| Cambrian Explosion | 450 million years ago life explodes on Earth. The continents are still barren but shallow ocean life is everywhere. |
| Carbiniferous period | 300 million years ago Earth is populated by giant tropical forests that housed giant insects and amphibians. |
| Center of the age of dinosaurs | 80 million years ago the Western USA not so much here was a great zone for dinosaurs. |
| Decline of the dinosaurs | 66 million years ago dinosaurs were already declining, but an asteroid that formed the Gulf of Mexico wiped out the big ones, leaving the small winged ones and underground mammals to survive this mass extinction. |
| Age of Megafauna | 2.5 million to about 11,500 years ago Sabertooth, Giant Sloths, Dire Wolfs etc... existed on Earth. |
| Ice Age happens | 1 million years ago The ice age happened and covered down to about Northern PA with ice. |
| Anthropocene | Present day (means age of humans). |
| What is accretion? | the process by which planets form, smaller objects collide and fuse together to form larger planets and moons. |
| Laurentia | refers to the North American Continent |
| what does Proterozoic look like | Most continents are in a shallow ocean, and Laurentia was buried under miles of ice |
| What was happening with Laurentia in the Cambrian Period? | Continents have moved down and are circling the South Pole. Laurentia moved towards the equator (straddling it) and was tipped on its side. |
| Age of Arthropods | (Arthro means jointed) and (pods means legs) |
| When does Pangea come together | During the Permian - early triasic periods 237 million years ago. |
| Alfred Wegener | (1880 - 1930) Was a German Earth scientist who propsed the theory of "Continental Drift" in a book published in 1915 titled "the origin continents and oceans". Theorized about Pangea forming and how were slowly drifting apart now. |
| Evidence of Pangea | Matching fossils across seperate continents, Mountain ranges and rock layers being the same across continents, Glaciation deposits matching up as well. |
| How many plates are there on Earth and how are they named? | 8 and they are named after the continent thats on it or Ocean. |
| James Usher | (1581 - 1656) Anglican Archbishop of Armough theorized in his book that the earth was created at sunday at noon at 4004 B.C. |
| Nicolaus Steno | lived in Italy (1638 - 1687) Developed basic principles (laws) regarding age relationships of sedimentary strata. |
| what were Stenos laws? | Principle of Superposition, Principle of Original horizontality, principle of lateral continuity. |
| Principle of superposition | Oldest layers are on the bottom and youngest layers are on the top (unless flipped or overturned) |
| Principle of original horizontality | sediments are deposited in horizontal or nearly horizontal layers |
| principle of original lateral continuity | Sediments are deposited over a large area in a continuous layer that may be traced laterally. |
| law of cross cutting | Rocks and faults that cut across layers must be younger than the rocks they cut through. The object cutting through other layers must be older. |
| James Hutton | Scottish geologist (1726 - 1797) often called the "father of modern geology". published the "theory of the earth in 1788". Basically said the Earth was formed through natural processes working over a very long period of time. |
| Unconformity | An ancient surface of erosion (or non deposition) seperating older rocks from younger rocks. |
| Nonconformity | Hardened lava that touches sedimentary rocks. |
| Angular unconformity | older rocks are folded or tilted under new rocks. |
| disconformity | a type of unconformity that marks a significant gap in the geologic record between two parallel, horizontal layers of sedimentary rock, where either layers were never deposited or were eroded away before new layers were deposited |
| William Smith | (1769 - 1839) First geological Map of Great Britain. Discovered that successive formations have distinctive fossils that can be used in correlation as indicators of relative age. |
| Principle of Fossil Succession | Fossils become much more complex within higher, more recent rock layers. Indicates a succession to more advanced life. |
| What was "The map that changed the world"? | First Geologic map of Great Britain |
| Charles Lyell | publishes "principles of Geology" (1830 - 1833). supports uniformitarionism and a slowly changing Earth. Worked on stratigraphy (how layers of rock formed and what they tell us.) |
| Law of included fragments | A sedimentary rock "conglomerate" composed of pebbles held together by a natural cementing matrix. The included pebbles are much older than the entire rock itself. |
| Uniformitarionism | The same natural events we see today took place in the past as well. Formed by James Hutton |
| 252 million years ago | 92% of life on Earth dies in a mass extinction |
| What percent of life on Earth do fossils show? | Fossils only represent about 10% of all past life forms. About 99% of all life on Earth has gone extinct by estimates. |
| New Definition of Fossil | The evidence of a living organism preserved in a "geologic context"(means that it must be preserved naturally in an Earth Process) |
| Body Fossil | The remains of past animals/plants/microorganisms. Can be bones, sheels, wood, leaves, mold etc... From it you can still figure out what it looked like. |
| Trace Fossil | Something that you know was left by a living organism but most of the time dont know by what. The evidence of biological activity like footpeints, piece of poop, burrows, trails, root traces. |
| What is the difference between fossilized and preserved? | When something is fossilized it is no longer originally what made it up but is now stone. Preservation is when something has little to no alteration of soft tissue or bone(still has DNA and stuff). |
| What are the conditions for best fossilization | Swept into water, have hard parts (bone/shells), then have rapid burial by sediment must escape normal decay process, the water has to have a lot of minerals in it (live a spring), over time the organic material gets replaced molecule by molecule. |
| Carbonization | the soft parts of the organism were compressed and heated, driving off all of the volatile(H,N,O). A carbon film is left and the animal has been vaporized. |
| Replacement | New material replaces the original skeleton; common replacement minerals include calcite, quartz and pyrite. |
| Mold | Skeletal hard part dissolved which results in a hole in the rock. Internal molds preserve the internal structure. |
| Cast | New material fills in natural molds, making a copy of what it looks like out of stone. |
| Permineralization | Minerals deposited in pore spaces (such as in wood and bone) also called petrification. (tends to be quartz or silica). Different colored perfect copy of what the thing looked like. Preserves fine details and cell structure. |
| Gastroliths | Piles of grinded stone found in the stomachs of fossils which were to help with food digestion |
| Lagerstatten | Locations scattered across the Earth where sedimentary rock layers contain exceptionally well preserved and abundant fossils. |
| Solnhofen Limestone | enormous variety of well preserved fossils. Discovered 3 new species here, such as the Pterosaurs (reptiles that flew and had feathers) |
| Archaeopteryx Fossil | Found in Solnholfen, fossil bird that was from the Jurassic (had feathers). Most important fossil discovery of this class because it had claws on it's wings and teeth (feathered dinosaur). |
| Anamolocaris Fossil | Found in Burgess shale (largest animal in Cambrian Ocean) |
| 541 million Years ago | profound changes in Earths Oceans |
| Precambrian | 88% of time on Earth, and Covers the first 3 Eons. Is the most difficult to study because not a lot left to study |
| Early Hadeon Eon | Earth was subjected to "heavy bombardment" of meteors and asteroids that consisted of rock and metal remaining from the formation of planets. Unstable and impossible for life. Probably no material left from this time. |
| The Hadeon Eon | The first water and atmosphere forms on Earth. The first rocks and continents too. the first atmosphere consisted of gases leftover from the solar nebula like Hydrogen Cyanide, Carbon dioxide, Carbon Monoxide (very toxic). |
| Formation of Earth's atmosphere by volcanoes | Volcanoes on newly formed Earth surface released atmospheric gases "outgassing" volcanic releases like water vapor, carbon dioxide, sulfur dioxide, sulfur dioxide, Nitrogen. No oxygen. Happened during the late Hadeon and pushed the toxic early atmosphere. |
| The Acasta Gneiss | the oldest known rocks; oldest known mineral grains 4.2 billion years old. |
| Jack Hills | 4.4 billion year old Zircon crystals found in Australian rock. |
| Erg Chech | meteorite landed in Algeria and is dated of 4.6 billion years old which is older than Earth. |
| The Archeon Eon | Earth has continents, oceans, atmosphere. Evidence of the first living things; microbes, Algae, and bacteria live and grow within the oceans, strange giant mushroom organisms form (one of the first organized ocean life forms). |
| Proterozoic Eon | 2.5 billion years ago an explosion of fossils and soft bodied life. Large oceans and stable continents. Abundant photosynthesis stromatolites begin to add oxygen to Earth's Atmosphere. |
| Stromatolites | cabbage shaped mushroom shaped organisms, living colony generic term for these organisms that grew on the floor of the ocean (mounds of algae and bacteria). 3 billion tears ago (probably longest living lineage). |
| Great Oxygenation Event | Earth's atmosphere begins to be filled with oxygen by stromatolites. |
| Banded Iron Formations (BIF's) | Oxygen released by stromatolites combines with the high amount of iron in the Ocean. The iron oxides settle to the ocean floor forming thick layers of BIF's Banded iron formations dated back to the Proterozoic Eon 2 BYA. |
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