Geology Final
Since its creation, the universe has been expanding for
13.8 billion years and recent observations suggest the rate of this expansion is increasing.
missing wavelengths were famously observed by
Joseph von Fraunhofer (1787-1826) in the early 1800s, but it took decades before scientists were able to relate the missing wavelengths to atmospheric filtering.
Laurasia consisted of
Laurentia and Eurasia
cratons
The stable interiors of the current continents. - mostly formed in the Archean Eon. - A craton has two main parts: the shield, which is crystalline basement rock near the surface, and the platform made of sedimentary rocks covering the shield.
Great Oxygenation Event
This drastic environmental change decimated the anaerobic bacteria, which could not survive in the presence of free oxygen. - On the other hand, aerobic organisms could thrive in ways they could not earlier.
Dinosaurs are split into two groups based on their hip structure
This is referred to as the "reptile hipped" saurischians and the "bird hipped" ornithischians. -Most of the dinosaurs of the Triassic were saurischians, but all of them were bipedal.
Darwin's On the Origin of Species
This study used a remarkable fossil of Archeopteryx from a transitional animal between dinosaurs and birds.
As the moving plates collided, the ocean basins closed to form
a supercontinent called Rodinia. - formed about 1 billion years ago and broke up about 750 to 600 million years ago, at the end of the Proterozoic. - One of the resulting fragments was a continental mass called Laurentia that would later become North America.
What is each beam of light?
a unique mixture of wavelengths that combine across the spectrum to make the color we see.
Geoscientists use the geological time scale to...
assign relative age names to events and rocks, separating major events in Earth's history based on significant changes as recorded in rocks and fossils.
started of the next eon, the Phanerozoic.
breakup created lots of shallow-water, biologically favorable environments that fostered the evolutionary breakthroughs.
The breaking points of each rifted plate margin
eventually turned into the passive plate boundaries of the east coast of the Americas today.
Vesto Slipher and Edwin Hubble
examined galaxies both near and far and found that almost all galaxies outside of our galaxy are moving away from each other, and us. - Because the light wavelengths of receding objects are extended, visible light is shifted toward the red end of the spectrum, called a redshift.
at the time of the K-T event Deccan Traps flood basalt volcanism in India.
it was certainly a large source of material hazardous to ecosystems at the time, and it has been suggested as at least partially responsible for the extinction. - Some have found the impact and eruptions too much of a coincidence and have even linked the two together.
Archean Eon
lasted from 4.0-2.5 billion years ago, is named after the Greek word for beginning. - This eon represents the beginning of the rock record. - There is current evidence that rocks and minerals existed during the Hadean Eon.
What is the Doppler effect is used on?
light emitted from stars and galaxies to determine their speed and direction of travel.
What do Astronomers think the big bang created?
lighter elements, mostly hydrogen and smaller amounts of elements helium, lithium, and beryllium. - Another process must be responsible for creating the other 90 heavier elements.
The Sonoma orogeny
marks the change in subduction direction to be toward North America with a volcanic arc along the entire west coast of North America.
Proterozoic Eon
meaning "earlier life," comes after the Archean Eon and ranges from 2.5 billion to 541 million years old. -most of the central parts of the continents had formed and plate tectonic processes had started. -Photosynthesis by microbial organisms, such as single-celled cyanobacteria, had been slowly adding oxygen to the oceans. - Great Oxygenation Event
The Earth and Moon are tidally locked
meaning that as the Moon orbits, one side always faces the Earth and the opposite side is not visible to us. - Also and most importantly, the chemical compositions of the Earth and Moon show nearly identical isotope ratios and volatile content.
By the end of the Cambrian
mollusks, brachiopods, nautiloids, gastropods, graptolites, echinoderms, and trilobites covered the sea floor.
lunar cataclysm
most of the Moons craters are from this event.
Spectroscopy shows that the Sun is
mostly made of hydrogen and helium.
The Hadean Eon
named after the Greek god and ruler of the underworld Hades - is the oldest eon and dates from 4.5-4.0 billion years ago. -Earth's earliest history, during which the planet was characterized by a partially molten surface, volcanism, and asteroid impacts. -Several mechanisms made the newly forming Earth incredibly hot: gravitational compression, radioactive decay, and asteroid impacts.
the crater where the bolide impacted.
not until 1991 that the crater was confirmed using petroleum company geophysical data. - third largest confirmed crater on Earth at roughly 180 km wide. -the Chicxulub Crater -In 2010, an international team of scientists reviewed 20 years of research and blamed the impact for the extinction.
Throughout the Mesozoic, animals on the isolated
now separated island continents (formerly parts of Pangea), took strange evolutionary turns. - This includes giant titanosaurian sauropods (Argentinosaurus) and theropods (Giganotosaurus) from South America.
Applying Spectroscopy to light from distant stars
scientists can calculate the abundance of elements in a specific star and visible universe as a whole. -can be used as an interstellar speedometer.
In 1977
scientists discovered an isolated ecosystem around hydrothermal vents on a deep-sea mid-ocean ridge (see Chapter 4) - it opened the door for another explanation of the origin of life.
The dinosaurs were relatively
small animals in the Triassic period of the Mesozoic, but became truly massive in the Jurassic.
Spectra is the plural for
spectrum which is a particular wavelength from the electromagnetic spectrum.
The XXVIth General Assembly of the International Astronomical Union (IAU)
stripped Pluto of planetary status in 2006 because scientists discovered an object more massive than Pluto, which they named Eris. - The IAU decided against including Eris as a planet, and therefore, excluded Pluto as well.
By the Mississippian (early Carboniferous) period
tetrapods had evolved into two main groups, amphibians and amniotes, from a common tetrapod ancestor.
An example of doppler effect
the same process that changes the pitch of the sound of an approaching car or ambulance from high to low as it passes.
tetrapods
(four-legged animals) such as amphibians
Pangea started breaking up
(in a region that would become eastern Canada and United States) -around 210 million years ago in the Late Triassic.
What do both rocky and gaseous planets have in similar?
- A similar growth model - Particles of dust, floating in the disc were attracted to each other by static charges and eventually, gravity. As the clumps of dust became bigger, they interacted with each other—colliding, sticking, and forming proto-planets. - The planets continued to grow over the course of many thousands or millions of years, as material from the protoplanetary disc was added. - Both rocky and gaseous planets started with a solid core.
evidence of early life
- Carbon found in 4.1 billion year old zircon grains have a chemical signature suggesting an organic origin. - old microscopic filaments from a hydrothermal vent deposit in Quebec, Canada.
What is the main phase of a star's life?
- Fusion -a star turns hydrogen into helium. Since most stars contain plentiful amounts of hydrogen, the main phase may last billions of years, during which their size and energy output remains relatively steady.
What are neutron stars?
- Larger stars may explode in a supernova that packs their mass even tighter to become neutron stars. - Neutron stars are so dense that protons combine with electrons to form neutrons.
The Doppler effect
- When an object emits waves, such as light or sound, while moving toward an observer, the wavelengths get compressed. In sound, this results in a shift to a higher pitch. - When an object moves away from an observer, the wavelengths are extended, producing a lower pitched sound.
During the Paleozoic Era, sea-levels rose and fell
- four times -With each sea-level rise, the majority of North America was covered by a shallow tropical ocean. -Evidence of these submersions are the abundant marine sedimentary rocks such as limestone with fossils corals and ooids.
the Cretaceous Western Interior Foreland Basin
-Tectonics had an influence -important geographic feature in North America. -which flooded during high sea levels forming the Cretaceous Interior Seaway: Subduction from the west was the Farallon Plate, an oceanic plate connected to the Pacific Plate (seen today as remnants such as the Juan de Fuca Plate, off the coast of the Pacific Northwest). caused a down warping in the central part of North America, High sea levels due to shallow subduction, and increasing rates of seafloor spreading and subduction, high temperatures, and melted ice also contributed to the high sea levels.
Geologists have reconstructed Rodinia by
-matching and aligning ancient mountain chains -assembling the pieces like a jigsaw puzzle - using paleomagnetic to orient to magnetic north.
What are the 3 criteria of the definition of a planet based on the IAU?
1) enough mass to have gravitational forces that force it to be rounded. 2) not massive enough to create fusion, and 3) large enough to be in a cleared orbit, free of other planetesimals that should have been incorporated at the time the planet formed. - Pluto passed the first two parts of the definition, but not the third. - Pluto and Eris are currently classified as dwarf planets.
the most reliable record for early life, the microfossil record, starts at..
3.5 billion years ago
there is significant fossil evidence for life at
3.5 billion years ago -first well-preserved fossils are photosynthetic microbial mats, called stromatolites, found in Australia.
There is possibly even evidence of life existing over...
4.0 billion yrs ago
late heavy bombardment
4.1-3.8 billion years ago, a second large spike of asteroid and comet impacted the Earth and Moon. -Meteorites and comets in stable or semi-stable orbits became unstable and started impacting objects throughout the solar system.
how much history do we have of Earth?
4.6 billion
led to a major mass extinction by the end of the Ordovician.
According to evidence from glacial deposits, a small ice age caused sea-levels to drop. - This is the earliest of five mass extinction events documented in the fossil record.
A Fusion example
An element such as hydrogen combines or fuses with other hydrogen atoms in the core of a star to become a new element, in this case, helium. - Another product of this process is energy, such as solar radiation that leaves the Sun and comes to the Earth as light and heat.
What continents dominate our planet?
Archean continents gave rise to the Proterozoic continents that now dominate our planet.
Cosmic radiation was accidentally discovered by
Arno Penzias and Robert Woodrow Wilson when they were trying to eliminate background noise from a communication satellite. - They discovered very faint traces of energy or heat that are omnipresent across the universe. - This energy was left behind from the big bang, like an echo.
temperature zones
As our solar system formed, the nebular cloud of dispersed particles developed distinct temperature zones. - Temperatures were very high close to the center, only allowing condensation of metals and silicate minerals with high melting points. -Farther from the Sun, the temperatures were lower, allowing the condensation of lighter gaseous molecules such as methane, ammonia, carbon dioxide, and water.
the Atlantic Ocean opened as the young Mid-Atlantic Ridge began to create the seafloor. This means the
Atlantic ocean started opening and was first formed here. The southern Atlantic opened next, with South America separating from central and southern Africa. Last (happening after the Mesozoic ended) was the northernmost Atlantic, with Greenland and Scandinavia parting ways.
Early life in the Archean and earlier
Based on chemical evidence and evolutionary theory, scientists propose this life would have been single-celled photosynthetic organisms, such as the cyanobacteria that created stromatolites.
Another likely source of water was from space
Comets are a mixture of dust and ice, with some or most of that ice being frozen water. - Seemingly dry meteors can contain small but measurable amounts of water, usually trapped in their mineral structures. - During heavy bombardment periods later in Earth's history, its cooled surface was pummeled by comets and meteorites, which could be why so much water exists above ground.
continental fragment
Continental crust that does not contain a craton. - island of Madagascar off the east coast of Africa.
The first vascular plant
Cooksonia, had woody tissues, pores for gas exchange, and veins for water and food transport.
What is the big-bang theory supported by?
Einstein's theory of general relativity, scientific evidence, grounded in empirical observations.
Ediacaran fauna
Fauna during the Ediacaran Period, 635.5 to 541 million years ago. soft-bodied organisms were among the first multicellular life forms and probably were similar to jellyfish or worm-like.
Why are gas giant planets different from rocky planets?
First, the original planetary nebula contained more gases and ices than metals and rocks. - There was abundant hydrogen, carbon, oxygen, nitrogen, and less silicon and iron, giving the outer planets more building material. - Second, the stronger gravitational pull of these giant planets allowed them to collect large quantities of hydrogen and helium, which could not be collected by weaker gravity of the smaller planets.
the Huron Glaciation.
Free oxygen reacted with methane in the atmosphere to produce carbon dioxide. Carbon dioxide and methane are called greenhouse gases. -the proportion of carbon dioxide in the atmosphere increased, the greenhouse effect decreased. -the planet cooled
What causes the elements to condense and spin into disk shape?
Gravitational attraction or perhaps a nearby stellar explosion.
the Nevadan Orogeny
In the Jurassic - another island-arc collision -a large Andean-style volcanic arc and thrust belt.
What forms a nebula?
In the tug-of-war between gravity's inward pull and fusion's outward push, gravity instantly takes over when fusion ends, with the outer gasses puffing away to form a nebula. -More massive stars do this as well but with a more energetic collapse, which starts another type of energy release mixed with element creation known as a supernova.
Permian Mass Extinction, also known as the Permian-Triassic Extinction Event.
It is estimated that up to 96% of marine species and 70% of land-dwelling (terrestrial) vertebrates went extinct. -Many famous organisms, like sea scorpions and trilobites, were never seen again in the fossil record.
nebular hypothesis
Our solar system formed at the same time as our Sun. -the idea that a spinning cloud of dust made of mostly light elements, called a nebula, flattened into a protoplanetary disk, and became a solar system consisting of a star with orbiting planets. - The spinning nebula collected the vast majority of material in its center, which is why the sun Accounts for over 99% of the mass in our solar system.
What are the differences between rocky and gas planets?
Rocky planets built more rock on that core, while gas planets added gas and ice. - Ice giants formed later and on the furthest edges of the disc, accumulating less gas and more ice. - That is why the gas-giant planets Jupiter and Saturn are composed of mostly hydrogen and helium gas, more than 90%. - The ice giants Uranus and Neptune are composed of mostly methane ices and only about 20% hydrogen and helium gases.
eukaryotes invented sexual reproduction.
Sharing genetic material from two reproducing individuals, male and female, greatly increased genetic variability in their offspring. - This genetic mixing accelerated evolutionary change, contributing to more complexity among individual organisms and within ecosystems
debate still exists over how and when powered flight evolved.
Some have stated a running-start model, while others have favored a tree-leaping gliding model or even a semi-combination: flapping to aid in climbing.
What are black holes?
The largest stars collapse their mass even further, becoming objects so dense that light cannot escape their gravitational grasp. -details of the physics of what occurs in them are still up for debate.
What is the Kuiper belt?
The outermost part of the solar system. -a scattering of rocky and icy bodies. Beyond that is the Oort cloud.
Silurian period
The period's major evolutionary event was the development of jaws from the forward pair of gill arches in bony fishes and sharks. - Hinged jaws allowed fish to exploit new food sources and ecological niches. -first evidence of terrestrial or land-dwelling plants and animals.
ice age during the Carboniferous period (called the Karoo Glaciation)
The reptiles fared much better than the amphibians, leading to their diversification. This glacial event lasted into the early Permian.
Cambrian Explosion
This sudden appearance of biological diversity. - Scientists debate whether this sudden appearance is more from a rapid evolutionary diversification as a result of a warmer climate following the late Proterozoic glacial environments, better preservation and fossilization of hard parts, or artifacts of a more complete and recent rock record.
The first lobe-finned land-walking fish
Tiktaalik - appeared about 385 million years ago and serves as a transition fossil between fish and early tetrapods.
Surrounding Pangea was
a global ocean basin known as the Panthalassa.
Continued plate movement extended the ocean into Pangea, forming
a large bay called the Tethys Sea that eventually divided the land mass into two smaller supercontinents, Laurasia and Gondwana.
What is in the center of this disk shaped nebula?
a new star is born under the force of gravity. - The spinning whirlpool concentrates material in the center, and the increasing gravitational forces collect even more mass. - Eventually, the immensely concentrated mass of material reaches a critical point of such intense heat and pressure it initiates fusion.
What is Fusion?
a nuclear reaction in which two or more nuclei, the centers of atoms, are forced together and combine creating a new larger atom. - This reaction gives off a tremendous amount of energy, usually as light and solar radiation.
therapsids
a second group of synapsids -evolve, and become the ancestors to mammals.
The Antler orogeny
a volcanic island arc that was accreted onto western North America with the subduction direction away from North America. - This created a mountain range on the west coast of North American called the Antler highlands and was the first part of building the land in the west that would eventually make most of California, Oregon, and Washington states.
What is the Oort cloud?
a zone filled with small and dispersed ice traces.
Hubble noticed that galaxies that were farther away from Earth...
also had the greater amount of redshift, and thus, the faster they are traveling away from us. The only way to reconcile this information is to deduce the universe is still expanding. Hubble's observation forms the basis of big-bang theory.
how many galaxies and solar systems does the universe have?
an infinite number
In the Jurassic, limbs (or a lack thereof) were also important to
another group of reptiles, leading to the evolution of Eophis, the oldest snake.
At the end of the Triassic
another mass extinction event occurred, the fourth major mass extinction in the geologic record. -perhaps caused by the Central Atlantic Magmatic Province flood basalt. - The end-Triassic extinction made certain lineages go extinct and helped spur the evolution of survivors like mammals, pterosaurs (flying reptiles), ichthyosaurs/plesiosaurs/mosasaurs (marine reptiles), and dinosaurs.
Toward the end of the Devonian
another mass extinction event occurred. This extinction, while severe, is the least temporally defined, with wide variations in the timing of the event or events. - Reef building organisms were the hardest hit, leading to dramatic changes in marine ecosystems
Eukaryotic cells
are more complex, having nuclei and organelles. - The nuclear DNA is capable of more complex replication and regulation than that of prokaryotic cells. -The organelles include mitochondria for producing energy and chloroplasts for photosynthesis. - The eukaryote branch in the tree of life gave rise to fungi, plants, and animals.
placoderms
armored fishes
The death of a star
can range from spectacular to other-worldly (see figure). - Stars like the Sun form a planetary nebula, which comes from the collapse of the star's outer layers in an event like the implosion of a building.
The origins of the universe and solar system set the
context for conceptualizing the Earth's origin and early history.
The first reptile (an amniote)
could live and reproduce entirely on land with hard-shelled eggs that wouldn't dry out.
What is the separation of minerals based on?
density and the creation of the crust, mantle, and core. - The earliest Earth was chiefly molten material and would have been rounded by gravitational forces so it resembled a ball of lava floating in space.
The Triassic saw
devastated ecosystems that took over 30 million years to fully re-emerge after the Permian Mass Extinction. -This includes frogs (amphibians), turtles (reptiles), marine ichthyosaurs and plesiosaurs (marine reptiles), mammals, and the archosaurs.
Common spectra include...
different colors of visible light, X-rays, ultraviolet waves, microwaves, and radio waves.
One of the best fossil sites for the Cambrian Explosion
discovered in 1909 by Charles Walcott (1850-1927) in the Burgess Shale in western Canada. - a site of exceptional fossil preservation that includes impressions of soft body parts. - Lagerstätte sites of similar age in China and Utah.
As oxygen continued to be produced and mineral precipitation leveled off
dissolved oxygen gas eventually saturated the oceans and started bubbling out into the atmosphere. - Oxygenation of the atmosphere is the single biggest event that distinguishes the Archean and Proterozoic environments.
gravitational resonance between Jupiter and Saturn
disturbing orbits within the asteroid and Kuiper belts based on a similar process observed in the Eta Corvi star system. - process must have caused the second increase in impacts hundreds of millions of years later.
angiosperm
dominated flora
What do Stars start their lives as?
elements floating in cold, spinning clouds of gas and dust known as nebulas.
Appalachian Mountains are
erosional remnants of these mountain building events in North America.
The current model of stellar evolution
explains the origins of these heavier elements.
These factors allowed a shallow epicontinental seaway that
extended from the Gulf of Mexico to the Arctic Ocean to divide North America into two separate land masses, Laramidia to the west and Appalachia to the east, for 25 million years. -Many of the coal deposits in Utah and Wyoming formed from swamps along the shores of this seaway. - By the end of the Cretaceous, cooling temperatures caused the seaway to regress.
The Sevier Orogeny
followed in the Cretaceous, which was mainly a volcanic arc to the west and a thin-skinned fold and thrust belt to the east, meaning stacks of shallow faults and folds built up the topography. - Many of the structures in the Rocky Mountains today date from this orogeny.
Mesozoic ("middle life")
from 252 million years ago to 66 million years ago. -As Pangea started to break apart, mammals, birds, and flowering plants developed. -best known as the age of reptiles, most notably, the dinosaurs.
Mammals
got their start from a reptilian synapsid ancestor possibly in the late Paleozoic.
By the end of the Paleozoic Era, the east coast of North America
had a very high mountain range due to continental collision and the creation of Pangea.
Phanerozoic organisms
had hard body parts like claws, scales, shells, and bones that were more easily preserved as fossils. - Rocks from the older Precambrian time are less commonly found.
white light from the Sun
has gaps in some wavelengths. The gaps correspond to elements present in the Earth's atmosphere that act as filters for specific wavelengths.
A segmented worm called Pikaia
is thought to be the earliest ancestor of the Chordata phylum that includes vertebrates, animals with backbones. - important ancestor to humans
hydrothermal vents
have a unique ecosystem of critters with chemosynthesis as the foundation of the food chain instead of photosynthesis. - The ecosystem is deriving its energy from hot chemical-rich waters pouring out of underground towers. - This suggests that life could have started on the deep ocean floor and derived energy from the heat from the Earth's interior via chemosynthesis.
What are White dwarfs?
hot star embers, formed by packing most of a dying star's mass into a small and dense object about the size of Earth.
Spectroscopy confirms that
hydrogen makes up about 74% of all matter in the universe
When is giant phase is predicted to happen to our Sun?
in another few billion years, growing the radius of the Sun to Earth's orbit, which will render life impossible. - The mass of a star during its main phase is the primary factor in determining how it will evolve. - If the star has enough mass and reaches a point at which the primary fusion element, such as helium, is exhausted, fusion continues using new, heavier elements.
The archosaurs ("ruling reptiles")
include ancestral groups that went extinct at the end of the Triassic, as well as the flying pterosaurs, crocodilians, and the dinosaurs. -occupied all major environments: terrestrial (dinosaurs), in the air (pterosaurs), aquatic (crocodilians) and even fully marine habitats (marine crocodiles).
Synapsids
including the famous sail-backed Dimetrodon are commonly confused with dinosaurs. - Pelycosaurs (of the Pennsylvanian to early Permian like Dimetrodon) are the first group of synapsids that exhibit the beginnings of mammalian characteristics such as well-differentiated dentition: incisors, highly developed canines in lower and upper jaws and cheek teeth, premolars and molars.
Where are light wavelengths are created or absorbed?
inside atoms, and each wavelength signature matches a specific element.
Eventually, fusion reaches its limit as it forms..
iron and nickel. This progression explains the abundance of iron and nickel in rocky objects, like Earth, within the solar system. - At this point, any further fusion absorbs energy instead of giving it off, which is the beginning of the end of the star's life.
An oxygenated world also changed the chemistry of the planet in significant ways
iron remained in solution in the non-oxygenated environment of the earlier Archean Eon. In chemistry, this is known as a reducing environment. - Once the environment was oxygenated, iron combined with free oxygen to form solid precipitates of iron oxide, such as the mineral hematite or magnetite. -These precipitates accumulated into large mineral deposits with red chert known as banded-iron formations, which are dated at about 2 billion years.
The end of the Paleozoic era
is marked by the largest mass extinction in earth history. -The Paleozoic era had two smaller mass extinctions, but these were not as large as the Permian Mass Extinction.
The Phanerozoic Eon
is the most recent, 541 million years ago to today, and means "visible life" because the Phanerozoic rock record is marked by an abundance of fossils.
The asteroid belt between Mars and Jupiter
is the source of most meteorites that currently impact the Earth. - Study of asteroids and meteorites help geologist to determine the age of Earth and the composition of its core, mantle, and crust. - Jupiter's gravity may also explain Mars' smaller mass, with the larger planet consuming material as it migrated from the inner to outer edge of the solar system.
The giant phase in a star's life
occurs when the star runs out of hydrogen for fusion. If a star is large enough, it has sufficient heat and pressure to start fusing helium into heavier elements. -This style of fusion is more energetic and the higher energy and temperature expand the star to a larger size and brightness.
Siberian Traps
one of the largest deposits of flood basalts known on Earth, dating to the time of the extinction event.
The volcanic outgassing hypothesis
origin of Earth's water is that it originated from inside the planet and emerged via tectonic processes as vapor associated with volcanic eruptions. - Since all volcanic eruptions contain some water vapor, at times more than 1% of the volume, these alone could have created Earth's surface water.
The main topics studied in Earth history
paleogeography, paleontology, and paleoecology and paleoclimatology
Angiosperms
plants with flowers and seeds
Sonoman Orogeny in Nevada
possible island-arc collision -during the latest Paleozoic to the Triassic.
Cyanobacteria
produced free oxygen in the atmosphere through photosynthesis. Cyanobacteria, archaea, and bacteria are prokaryotes—primitive organisms made of single cells that lack cell nuclei and other organelles.
giant-impact hypothesis
proposes a body about half of Earth's size must have shared at least parts of Earth's orbit and collided with it, resulting in a violent mixing and scattering of material from both objects. - Both bodies would be composed of a combination of materials, with more of the lower density splatter coalescing into the Moon. - This may explain why the Earth has a higher density and thicker core than the Moon.
One important evolutionary advancement during the Ordovician Period
reef-building organisms, mostly colonial coral. - Corals took advantage of the ocean chemistry, using calcite to build large structures that resembled modern reefs like the Great Barrier Reef off the coast of Australia.
Gondwana consisted of
remaining continents of South America, Africa, India, Australia, and Antarctica.
Miller-Urey experiment
researchers simulated early Earth's atmosphere and lightning within a sealed vessel. - After igniting sparks within the vessel, they discovered the formation of amino acids, the fundamental building blocks of proteins.
The Phanerozoic is subdivided into three eras
rom oldest to youngest they are Paleozoic ("ancient life") Mesozoic ("middle life") Cenozoic ("recent life")
Carboniferous (North American geologists have subdivided this into the Mississippian and Pennsylvanian periods)
saw the highest levels of oxygen ever known, with forests (e.g., ferns, club mosses) and swamps dominating the landscape. - This helped cause the largest arthropods ever, like the millipede Arthropleura, at 2.5 meters (6.4 feet) long! -saw the rise of a new group of animals, the reptiles. -created cooling temperatures as carbon dioxide was removed from the atmosphere. - By the middle Carboniferous, these cooler temperatures led to an ice age
Apollo missions returned from the Moon with rocks...
that allowed scientists to conduct very precise comparisons between Moon and Earth rocks. - Other bodies in the solar system and meteorites do not share the same degree of similarity and show much higher variability. -If the Moon and Earth formed together, this would explain why they are so chemically similar.
There is evidence that submerged masses like Zealandia
that includes present-day New Zealand, would be considered a continent.
most basic animal body plans appeared in the rock record during
the Cambrian Period
Near the end of the Paleozoic Era
the Carboniferous Period had some of the most extensive forests in Earth's history. - Their fossilized remains became the coal that powered the industrial revolution
During late heavy bombardment
the Earth, Moon, and all planets in the solar system were pummeled by material from the asteroid and Kuiper belts. Evidence of this bombardment was found within samples collected from the Moon.
Mesozoic Era ended with
the K-Pg Mass Extinction (previously known as the K-T Extinction) - 66 million years ago -likely caused by a large bolide (an extraterrestrial impactor such as an asteroid, meteoroid, or comet) that collided with earth. Ninety percent of plankton species, 75% of plant species, and all the dinosaurs went extinct at this time. -evidence comes from the element iridium. -a special type of "shocked" quartz called stishovite, that only is found at impact sites, was found in many places around the world. The huge impact created a strong thermal pulse that could be responsible for global forest fires, strong acid rains, a corresponding abundance of ferns, the first colonizing plants after a forest fire, enough debris thrown into the air to significantly cool temperatures afterward, and a 2-km high tsunami inferred from deposits found from Texas to Alabama.
The first fully terrestrial tetrapod arrived in
the Mississippian (early Carboniferous) period.
the midcontinent has extensive marine sedimentary rocks from
the Paleozoic and western North America has thick layers of marine limestone on block faulted mountain ranges such as Mt. Timpanogos near Provo, Utah.
A large evolutionary step occurred during the Proterozoic Eon
the appearance of eukaryotes around 2.1 to 1.6 billion years ago.
What is a supernova?
the collapse of the core suddenly halts, creating a massive outward-propagating shock wave. - A supernova is the most energetic explosion in the universe short of the big bang. - The energy release is so significant the ensuing fusion can make every element up through uranium.
What can the death of the star can result in?
the creation of white dwarfs, neutron stars, or black holes. - Following their deaths, stars like the Sun turn into white dwarfs.
The first solid evidence of modern plate tectonics is found at..
the end of the Archean. indicating at least some continental lithosphere must have been in place.
The transition of soft-bodied Ediacaran life to life forms with hard body parts occurred at
the end of the Proterozoic and beginning of the Phanerozoic Eons. - made a dramatic difference in scientists' ability to understand the history of life on Earth.
The beginning of the Paleozoic Era is marked by
the first appearance of hard body parts like shells, spikes, teeth, and scales; and the appearance in the rock record of most animal phyla known today.
animals that do not fit existing lineages and are unique to that time
the first compound-eyed trilobites; Wiwaxia, a creature covered in spiny plates; Hallucigenia, a walking worm with spikes; Opabinia, a five-eyed arthropod with a grappling claw; and Anomalocaris, the alpha predator of its time, complete with grasping appendages and circular mouth with sharp plates.
The saurischians diversified into
the giant herbivorous (plant-eating) long-necked sauropods weighing up to 100 tons and bipedal carnivorous theropods, with the possible exception of the Therizinosaurs. - All of the ornithischians (e.g Stegosaurus, Iguanodon, Triceratops, Ankylosaurus, Pachycephhlosaurus) were herbivorous with a strong tendency to have a "turtle-like" beak at the tips of their mouths.
how continents were made in the first place is not easily answered because
the great age of continental material and how much evidence has been lost during tectonics and erosion.
What formed solid slabs of early crust?
the high melting-point minerals
What did temperature differentiation result in?
the inner four planets of the solar system becoming rocky, and the outer four planets becoming gas giants.
What is Spectroscopy?
the investigation and measurement of spectra produced when materials interacts with or emits electromagnetic radiation.
Life most likely started during
the late Hadean or early Archean Eons. - The earliest evidence of life are chemical signatures, microscopic filaments, and microbial mats.
What caused such a widespread extinction event? (Permian Mass Extinction)
the leading idea relates to extensive volcanism associated with the Siberian Traps. -The eruption size is estimated at over 3 million cubic kilometers that is approximately 4,000,000 times larger than the famous 1980 Mt. St. Helens eruption in Washington. - would have contributed a large amount of toxic gases, aerosols, and greenhouse gasses into the atmosphere. -the volcanism burned vast coal deposits releasing methane (a greenhouse gas) into the atmosphere, could have acidified the oceans, disrupted food chains, disrupted carbon cycling, and caused the largest mass extinction.
Due to sea-floor spreading
the oldest rocks on the Atlantic's floor are along the coast of northern Africa and the east coast of North America, while the youngest are along the mid-ocean ridge.
differentiated the Earth from a homogenous planet into a heterogeneous one
the planet becoming layers of felsic crust, mafic crust, ultramafic mantle, and iron and nickel core.
The western edge of North American continent was near
the present-day Nevada-Utah border and was an expansive shallow continental shelf near the paleoequator.
What did Jupiter's massive gravity further shape?
the solar system and growth of the inner rocky planets. - As the nebula started to coalesce into planets, Jupiter's gravity accelerated the movement of nearby materials, generating destructive collisions rather than constructively gluing material together. - These collisions created the asteroid belt, an unfinished planet, located between Mars and Jupiter.
Permian
the supercontinent led to a dryer climate, and even more diversification and domination by the reptiles. - radiated into dinosaurs. - Another group, known as the synapsids, eventually evolved into mammals.
big-bang theory proposes
the universe was formed from an infinitely dense and hot core of material. The bang in the title suggests there was an explosive, outward expansion of all matter and space that created atoms.
Reefs are important to paleontologists because of
their preservation potential, massive size, and in-place ecosystems.
During the Great Ordovician Biodiversification Event
vertebrates and invertebrates (animals without backbone) became more diverse and complex at family, genus, and species level. - still debated but some likely causes are a combination of warm temperatures, expansive continental shelves near the equator, and more volcanism along the mid-ocean ridges. -Some have shown evidence that an asteroid breakup event and consequent heavy meteorite impacts correlate with this diversification event. -The additional volcanism added nutrients to ocean water helping support a robust ecosystem.
The easiest way to create continental material is
via assimilation and differentiation of existing continents
must have brought the first continental material to the Earth's surface during the Hadean, 4.4 billion years ago.
volcanic action
Explanations for the origin of Earth's water include...
volcanic outgassing, comets, and meteorites
Pangea, sometimes spelled Pangaea
was completed by the late Paleozoic Era. - The name Pangea was originally coined by Alfred Wegener and means "all land." - In North America, these tectonic events occurred on the east coast and are known as the Taconic, Acadian, Caledonian, and Alleghanian orogenies.
Life in the early Paleozoic Era
was dominated by marine organisms but by the middle of the era plants and animals evolved to live and reproduce on land.
The amphibians
were able to breathe air and live on land but still needed water to nurture their soft eggs.
Proterozoic land surfaces
were barren of plants and animals and geologic processes actively shaped the environment differently because land surfaces were not protected by leafy and woody vegetation. -resulted in thick accumulations of pure quartz sandstone from the Proterozoic Eon such as the extensive quartzite formations in the core of the Uinta Mountains in Utah.
The Kuiper belt and Oort cloud is where
where most comets form and continue to orbit, and objects found here have relatively irregular orbits compared to the rest of the solar system. Pluto, formerly the ninth planet, is located in this region of space.
at the time of the K-T event sea levels are known to be slowly decreasing
which is tied to marine extinctions, though any study on gradual vs. sudden changes in the fossil record is flawed due to the incomplete nature of the fossil record.
sea-level falls are documented by
widespread unconformities
During the Mesozoic Era, the size of the mountains on either side of North America would flip
with the west coast being a more tectonically active plate boundary and the east coast changing into a passive margin after the breakup of Pangea.
Phanerozoic rocks are
younger, more common, and contain the majority of extant fossils