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72 Cards in this Set
- Front
- Back
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In outer space, what are gas clouds called?
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Nebula
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What are the most abundant gases in a nebular cloud?
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Hydrogen and Helium
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What are the currents in the cloud formed by?
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gravity
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What happens to the central mass of a nebula cloud?
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o As the mass at the center gets larger it will eventually get so large that it forms a “protostar.”
o Soon the protostar is hot enough to start the process of nuclear fusion (atoms forced together). |
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What happens to the gas and dust that is not pulled into the central mass?
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o The remaining material around the new star is called a solar nebula
-o The solar nebular start to collide and basically stick together forming something even bigger. |
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What are the characteristics of the planets closest and farthest from the sun?
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• The planets closest to the sun are generally smaller and rocky
• The planets farther away form the sun were larger and mostly gaseous |
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What are asteroids?
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mostly in the asteroid belt (between mars and Jupiter). Never were created into planets. Most of the asteroids are made of rock and metal
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What are comets?
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live in the Kupier belt. On the outside of the solar system. Made mostly of ices—not only water ice but methane ice and ammonia ice.
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What happened at the accretion of the planets?
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Accretion (come together) of planets~4.56 billion years ago.
• Started at homogenous • Now it is Layered, not homogenous • Melting of the earth so all the iron went to the center |
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Where did the heat of the Earth originate from?
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• To get melting you need heat. It came from 1)radioactivity.
o When radioactive elements decay the give off radioactivity and heat. There is a lot of radioactive elements in the Earth o 2) heat came from collisions. The kinetic energy that provides the speed of the collisions is converted into heat upon impact. |
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What happened when Theia and Earth collided?
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o The Earth and another planet called Theia collided. Theia was about the same size as Earth. Thea was totally vaporized and tore off a huge piece of the Earth and pumped a lot of heat into the Earth system.
• This turned the Earth’s surface into a magma ocean • Material form the Earth was thrown into space, the Earth was knocked off its axis by 23˚. • Particles from the Earth collected in the orbit and created the moon. |
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What was the "first" atmosphere made of?
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• The “first” atmosphere was made of hydrogen and helium
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What was the "second" atmosphere made of?
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• Because of the continued volcanism, the “second” atmosphere is carbon dioxide, water vapor, and nitrogen. Very little (less than 1%) oxygen at this time.
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What is today's atmosphere like?
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o Today the atmosphere is about 21% oxygen
o Not until 2billion years ago, oxygen in the atmosphere got close to today’s levels. o There was no ozone layer at the beginning, because it needs oxygen. –ozone stops UV rays. So high UV radiation at beginning. o There is a zircon crystal found in west Australia that is 4.4 billion years old. This suggest that at this time the Earth had a solid surface and the structure of the crystal also suggests it was exposed to water. |
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What is the late heavy bombardment period?
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• About 3.9 billion years ago the Earth underwent the late heavy bombardment period. This is when most of the craters of the moon were formed.
o No one knows why the rate of bombardment increased. • Popular theory is that one or more of the gas giants shifted in their orbits. • So was there life before the period of LHB and was extinguished? |
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What are some characteristics of microbes?
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• Most abundant form of life of Earth
• Single celled • All organisms we call bacteria, fungi and algae, protozoa. • 1/1,000 mm • Exist in: Air, Soil, inside rocks, roots of plants, toxic waste, snow fields, every type of water (incl. hot springs). • Have been found 5 km below the surface and 10 km into the atmosphere. • Can live at temperatures from -20˚C to 100˚C • Very abundant where they occur. 10 cubed – 10 to the 9th per cubic cm • Most genetically diverse organisms on the Earth |
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What are some characteristics of bacteria?
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o Probably evolved first
o Single celled microorganisms |
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What is a characteristic of archea?
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o Most tolerant of high temperatures
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What are some characteristics of Eukarya?
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o evolved later
o More complex internal structure o Amoebas. o Least tolerant of high temperatures |
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What are extremophiles?
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• Microbes that can eat almost anything
o Oil, toxic waster, nitric acid, sulfuric acid, iron, arsenic, even radioactive substances. |
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What are acidophiles?
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Live in acidic environments?
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What are thermophiles?
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o Live in very hot environments ( 50-70˚C or 120-160˚F)
o Can tolerate temps of 120˚C or 250˚F |
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What are halophiles?
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o Live in extremely salt environments
o Up to 10X the concentration of salt in sea water o Dead sea, great salt lake, and salt extraction from salt water. |
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What are anaerobes?
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o Live in low oxygen environments
o Bottoms of lakes, rivers, and seas. o Even in pore spaces of sediments |
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What are aerobic microbes?
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o Live in oxygen rich environments
o Sometimes the line between oxygen rich and oxygen starved is well defined. |
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What are prokaryotes?
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• Bacteria
• Archea o Prokaryotic cells • Generally small, simple structure, no cell nucleus |
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What are eukaryotes?
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o Eukaryotic cells
• Generally large and have complex internal stucture. • Their DNA is in a cell nucleus • Structures inside the cell called organielles—like the mitochondrion. It is thought that these were originally prokaryotic cells. |
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What is Taphonomy?
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how a living organisms become fossils, “life” cycle of fossils—what effects fossilization
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Where are fossils usually found?
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• Can be found in sediments, coal, tar, oil, amber, volcanic ash, frozen in ice, mummified
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What part of the animal is usually preserved?
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• The entire organism is hardly even preserved. Pieces that are missing are the soft parts (skin, organs etc.)
• Most common things you can find as fossils are organisms with hard parts—skeleton, shell, lignin (plants), exo-skelton |
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What is the first step to becoming a fossil?
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1.DIE. Die in a place where you’re going to be buried quickly—sediments laid down on top of you. OR have your body moved there very quickly.
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What is the second step in becoming a fossil?
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Burial
o Lakes, lagoons, bends in a river, or the ocean floor. |
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What is the third step in becoming a fossil?
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3. FOSSILIZATION. Transforms essentially into a rock. The sediments are lithified and become sedimentary rock. (hundreds and thousands of years.
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What is the last step in becoming a fossil?
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4. EROSION. The fossil is lifted from the earth through plate tectonics or some other events and wear away enough sedimentary rock that the fossil is exposed to the air, and then it can be collected.
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How could the soft parts of an organism be preserved?
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• If the soft parts are to be preserved, it would have to be buried under some kind of anoxic condition (one that has little to no oxygen—bottom of lakes or ocean floor).
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What is the most common kind of fossilization?
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• most common) Permineralization. Dinosaur bones.
o Inside of all bones are pores. Bone is buried in sediments under water, there is ground water the percolates through the sediments. The ground water has dissolved minerals in it which fill in the pores in the bone and crystallizes. Over time all of the pore spaces will be filled with crystals. • Ex. Petrified wood. |
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What is replacement fossilization?
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o Actual parts of the bone or shell are replaced. NO bone (or whatever) material is left. Complete replica—structure is the same, but the minerals are replaced.
o Happens a lot with sea creatures—have shells etc. made up of aragonite->unstable form of calcium carbonate. So Aragonite is replaced with calcite. |
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What is casts and molds fossilization?
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o The fossil is removed and only a space is left, this is called a mold.
o The cast—shell gets buried and the shell dissolves. At some point some other sediment fills up the space and so there is a replica of the shell or whatever is made of sediment. |
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What is carbonization fossilization?
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o All of the volatile elements in the organism after its buried are driven off (oxygen, nitrogen). What is left is a carbon residue.
o Often with plant fossils. o A film of carbon ont eh surface of the rock |
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What is unaltered preservation
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A kind of fossilization
o The Rarest. When an organism dies and is buried and nothing happens to it and it can be recovered in a state close the state it was when alive. o Original tissue. o Usually occurs in tar, ice, or amber. o No chemical processes |
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Where did the chemical elements that make up the Earth come from?
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Exploding Supernovas
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What space objects help scientists study the early Earth?
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Meteorites
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How do scientists estimate the age of the solar system?
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By dating meteorites (the leftovers of the planetesimals)
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What was the surface of Earth like during its early years?
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Magma ocean
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Why is Earth’s magnetic field important?
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It protect the Earth from the solar wind
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What was surprising about the chemistry of moon rocks?
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They were very similar to the rocks of earth’s crust
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How was the moon formed?
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By the collision of a Mars-sized planet & Earth. Debris from the collision
collected in orbit & formed the Moon |
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In what two ways did water get to Earth’s surface?
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Volcanoes and comets
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What does the “Rare Earth” theory suggest?
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Simple life may be common but complex life may be very rare – complex life
may require an intricate series of random events |
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What happened when Earth & Theia collided?
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Theia was destroyed
Earth grew larger – increased gravity |
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What might have happened to Earth’s atmosphere if the planet had been smaller?
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There wouldn’t have been enough gravity to hold it…it would have leaked
into space |
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What are 2 reasons why we don’t see more meteorite craters on Earth?
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Erosion destroys the evidence
The atmosphere burns most meteorites up |
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How do plate tectonic processes help regulate Earth’s temperature?
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Volcanoes emit CO2 which helps warm the surface
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How has CO2 been important to life on Earth?
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Keeps the surface warm enough for life
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How does the moon affect water on Earth?
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Pulls the oceans toward it – causes the tides
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What have laser measurements of the moon’s orbit shown?
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The moon is slowly moving away
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What 3 things did the collision of Earth & Theia provide the Earth?
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Atmosphere (from increased gravity)
Magnetic shield (increased iron in core) Moon |
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What is special about Earth’s location in the Solar System?
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It is the zone where liquid water can exist
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Why is the type of star at the heart of a solar system important to the development of complex life?
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Its life cycle is long enough to sustain complex life on earth. Larger suns burn up faster
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How is a planet like jupiter essential to complex life on Earth?
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It deflects dangerous objects
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How did the impact at Chicxulub prove to be important to humans?
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Extinction of the dinosaurs made room for the rise of mammals
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Why are some catastrophes a good thing for life?
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They can kick-start evolutionary change by making room for new
organisms |
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What is the Anthropocene?
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The most recent geological era – dominated by humans
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The amount of forest cleared each year is the size of what state?
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South Carolina
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What were the first organisms most likely like?
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At about 3.85 Ga we see evidence of carbon isotopes in rocks ( of that age)
• Suggest that the processes that we associate with living organisms are occurring—life exists • Simple metabolic processes, single-celled • Thrive in a environment right in carbon dioxide, nitrous oxide, hydrogen sulfide, ammonia and methane. o Clearly oxygen is missing. No ozone • Any organisms would have to be anaerobic • The first organisms would have been heterotrophic—they relied on outside sources for their nutrients. • Autotrophic organisms make their own nutrients. Plants • The first organisms would have been prokaryotes—single celled |
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What was the biggest event of the Archean era?
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Development of photosynthesis
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What about photosynthesis?
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o The best evidence says that photosynthesis evolved as a life strategy about 300 Ga
o Photons take their energy from the sun, carbon dioxide and water. o They use that to produce complex carbohydrates o They produce oxygen as their waste product o So Co2 +H2O+light-->(CH20)+O2 |
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Where are the oldest fossils found?
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• Oldest fossils undisputed fossils found in south Africa and are about 3Ga. But the oldest probable fossils are 3.3-3.5 Ga and are found in warrawoona in Australia
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What are the oldest fossils?
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o These fossils are called stromatolites—basically mounds of sediment full of bacteria.
o They are evidence of a cyanobacteria—we still have the ones responsible. o A stromatolite is a trace fossil—the working of the bacteria not the actually bacteria. Yet there are the fossils in the same rock of the cyanobacteria as well—the body fossil. |
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What is cyanobacteria?
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• Cyanobacteria are single-celled, use photosynthesis, are prokaryotes
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What catastrophe can wipe out microbes?
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There is no catastrophe that can completely wipe out extremophile prokaryotes because they can adapt to almost any environment.
• They are evolutionally stagnant because they produce Asexually (essentially cloning). |
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What is the leading theory of how the planets formed?
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The solar nebula theory
o The solar nebular (gas and dust) start to collide and basically stick together forming something even bigger. o The small bodies that form are called planetesimals. They grow because as the get bigger they attract more particles. • The planets closest to the sun are generally smaller and rocky • The planets farther away form the sun were larger and mostly gaseous |
