History of the Earth – Flashcards
Unlock all answers in this set
Unlock answersquestion
catastrophism
answer
theory that Earth's rock layers formed in a global flood followed by the uplifting of rocks and mountain building over a short, violent period, possibly in the recent past
question
gradualism
answer
theory that rocks form slowly over time through processes of volcanism, erosion, and sedimentation
question
molecular clock
answer
a technique for estimating the age of species by comparing molecular differences between species
question
sediment
answer
dirt, pieces of rock, and the remains of living things at the bottom of oceans, seas, and lakes
question
uniformitarianism
answer
geologic principle that Earth's processes act in the same manner today as they always have throughout Earth's history
question
What are the three types of biological evidence of the age of the earth?
answer
The fossil record Comparative anatomy Molecular clocks
question
What are the three types of geological evidence of the age of the earth?
answer
Gradual processes of rock formation The fossil record Radioactive dating
question
What are the two types of astronomical evidence of the age of the earth?
answer
The movement of galaxies Chemical composition of the Sun
question
How old is the Earth?
answer
4.6 Billion Years Old
question
index fossil
answer
a fossil that is widespread geographically but only occurs in one layer or a small number of layers of rock
question
law of cross-cutting (or intrusive) relationships
answer
in a sequence of layered rocks, the crosscut, or intrusive feature, is younger than the layers it intercedes
question
law of faunal and floral succession
answer
animals and plant fossils occur in consistent sequences through time, generally changing from simpler to more complex
question
law of original horizontality
answer
sediment deposited into water will settle at the bottom in flat, horizontal layers
question
law of original lateral continuity
answer
sediment deposited into water will spread in a horizontal and continuous sheet, unless it runs out of sedimentary material, or it hits a barrier
question
law of superposition
answer
any undisturbed sequence of layered rocks has the oldest rock on the bottom and newest rock on the top
question
paleontology
answer
study of fossils
question
relative dating
answer
process to determine the general time sequence of historic events, rock strata, and fossils
question
stratigraphy
answer
study of rock layers and the processes that form them
question
absolute time
answer
geologic time measured in a specific duration of years
question
molecular clock
answer
a technique for estimating the age of species by comparing molecular differences between species
question
radioactive decay
answer
spontaneous disintegration of the atoms of certain isotopes into new isotopes
question
radiometric dating
answer
dating a rock or mineral by measuring the proportions of an original radioactive material and its decay products
question
relative time
answer
placing events in chronological order without reference to their ages measured in years
question
What is a half-life?
answer
the time it takes for half of the atoms of an element to change from parent to daughter atoms
question
What do some biologists question about absolute dating?
answer
some biologists question whether rates of change in biological molecules are constant enough to use molecular clocks to measure how long ago changes in species occurred
question
The rate at which a parent atom creates daughter atoms is always _____.
answer
constant and unique
question
What do you need to know for radiometric dating?
answer
the rate at which radioactive decay occurs how much radioactive decay has occurred
question
"Dinosaurs went extinct 65 million years ago." This statement is an example of _____.
answer
absolute time
question
"Fish appear in the fossil record before amphibians." This statement is an example of _____.
answer
relative time
question
eon
answer
longest interval of geologic time
question
era
answer
major divisions of geologic time within each eon; identified by major changes in the fossil record
question
eukaryotic
answer
a cell that has complex internal structures, such as a nucleus; e.g., plant and animal cells
question
period
answer
major divisions of geologic time within each era; identified by changes in the fossil record
question
prokaryotic
answer
a simple cell that lacks complex internal structures, e.g., bacterial cells
question
stromatolites
answer
fossil mounds made of ancient photosynthetic bacteria, flourished during Archean
question
Describe the Hadean Eon.
answer
4.5 to 3.8 billion years ago not a geologic time interval, no rocks asteroids and large meteorites were still bombarding the new planets release of heat from these collisons made the Earth molten at this time formation of the color system
question
Describe the Achrean Eon.
answer
3.8 to 2.5 Billion Years Ago began when the surface of the Earth was cooled full of poisonous gases; methane, ammonia, and other toxic gases from volcanic activity first fossils began (3.5 billion years ago), ancient bacteria
question
What type of cell are bacteria and archea?
answer
prokaryotic
question
Where can you find the oldest known fossil stromatolites?
answer
Western Australia
question
Describe the Proterozoic Eon.
answer
2.5 Billion to 543 Million Years Ago first fossils of eukaryotic cells stable continents formed oxygen build up from photosynthetic bacteria such as stromatolites explosion of multicellular life forms, especially plants towards end, first simple animals
question
Why was this oxygen build up and new eukaryotes dangerous to bacteria?
answer
compete with other organisms
question
Describe the Phanerozoic Eon.
answer
543 Million Years Ago to the Present first appearance of hard-shelled animals evolution of bony fish and all forms of land plants and animals divided into eras; Paleozoic, Mesozoic, and Cenozoic
question
What divides the Phanerozoic Eon into its three eras?
answer
Significant changes in the fossil record
question
Describe the Paleozoic Era.
answer
543 to 248 Million Years Ago 1. an "explosion" of new life begins with Cambrian explosion small, shelled animals, such as trilobites, brachiopods, mollusks, and different types of corals ruled the ocean land plants grew rapidly Animals with bones—vertebrates—came next. 2. the largest mass extinction killed off almost 90% of all marine animal species still debating its cause
question
Describe the Mesozoic Era.
answer
248 to 65 Million Years Ago means middle animals dinosaurs dominate Divided into: Triassic - dinosaurs first appeared, Jurassic - diverse dinosaurs Cretaceous ended with mass extinction, ended by a meteor, all dinosaurs and certain land animals, small mammals and birds lived
question
Describe the Cenozoic Era.
answer
65 Million Years to the Present age of mammals misnamed because birds, insects, and flowering plants also dominate it
question
basaltic
answer
common gray to black volcanic rock, usually fine-grained due to rapid cooling of lava
question
glaciation
answer
the advance and retreat of large masses of slow-moving ice
question
mass extinction
answer
the process in which huge numbers of species die out suddenly
question
rifting
answer
process by which the earth's crust is pulled apart and new crust forms
question
What do scientist believe are behind mass extinctions?
answer
the disasters come either from above, in the form of deadly asteroids or comets, or from below, in the form of extreme volcanic activity
question
When did all of the mass extinctions occur?
answer
Phanerozoic Eon
question
Describe the Ordovician-Silurian Extinction.
answer
440 million years ago earliest extinction in history second largest extinction in history associated with a period of glaciation (the formation and retreat of glaciers) before, shallow, warm, continental seas were the perfect environment for many groups of organisms 60% of marine species was lost glaciation affected tropics
question
What is a list of possible causes of the Ordovician-Silurian Extinction?
answer
climatic cooling major glaciation sea level drop
question
What died in the Ordovician-Silurian Extinction?
answer
tropical animals such as bryozoans and brachiopods (half were gone)
question
Describe the Late Devonian Extinction.
answer
364 million years ago about 20% of all animal families and 70-80% of all animal species were lost profound changes in oceanology from loss of tabulate corals and stromatoporoids
question
What do scientists believe caused the Late Devonian Extinction?
answer
asteroids hitting the earth the growth of forests climatic changes sea level changes
question
What is the Devonian Plant Hypothesis?
answer
The growth of forests that led to environmental changes and subsequent cooling.
question
What died in the Late Devonian Extinction?
answer
conodonts jawless fish rugose and tabulate corals stromatoporoid sponges trilobites
question
Describe the Permian-Triassic Extinction.
answer
251 million years ago worst mass extinction 95% of all species on planet 70% of all land species, such as plants, insects, and vertebrate animals 96% of the planet's marine species lost many scientists suspect a comet or asteroid impact (no evidence or crater to prove that) massive volcanism from the Siberian Traps and a related loss of oxygen in the seas
question
What is the most common theory behind the Permian-Triassic Extinction?
answer
an asteroid impact triggered massive volcanism
question
What are the possible causes of the Permian-Triassic Extinction?
answer
asteroid hitting the earth massive volcanism producing climate change and related loss of oxygen in the seas combination of an asteroid and volcanism
question
Describe the End Triassic Extinction.
answer
199 million to 214 million years ago 58 cephalopod families disappeared killed 52 percent of marine species occurred in a series of stages conodonts extinct Only 11 of 50 reef organisms survived
question
What are the possible causes of the End Triassic Extinction?
answer
rifting of the earth global warming
question
Describe the Cretaceous-Tertiary Extinction.
answer
a.k.a the K-T extinction 65 million years ago killed off the dinosaurs an asteroid impact - created the Chicxulub crater at the tip of Mexico's Yucatán Peninsula dinosaurs, pterosaurs, plesiosaurs, mosasaurs, ammonites, and some families of birds and marsupial mammals half the plankton groups, many families of teleost (bony) fishes, bivalves, snails, sponges, sea urchins, and others
question
Explain the the asteroid impact associated with the "K-T Extinction".
answer
created the Chicxulub crater at the tip of Mexico's Yucatán Peninsula caused huge fires, tsunamis, severe storms with high winds, highly acidic rain, seismic activity, and perhaps even volcanic activity
question
What are a list of possible reasons for the Cretaceous-Tertiary Extinction?
answer
an asteroid hitting the earth volcanism
question
atmosphere
answer
the gaseous envelope of a planet
question
climate
answer
long-term weather patterns of a particular area
question
Greenhouse Effect
answer
warming of the atmosphere caused by gases that absorb heat from Earth's surface
question
outgassing
answer
to lose gases into the atmosphere
question
Pangea
answer
supercontinent which connected the landmasses of the southern and northern hemispheres interior was extremely hot and dry majority of the land was nowhere near the ocean and had very little rainfall
question
What does our atmosphere contain?
answer
nitrogen (78%), oxygen (21%), and other gases (1%)
question
paleoatmosphere
answer
early atmosphere
question
The early atmosphere was _______.
answer
poisonous mostly carbon dioxide hot
question
What are the main functions of our atmosphere?
answer
protect us by filtering out deadly cosmic rays helps protect us from meteors on a collision course with Earth a role in sustaining life
question
What did our early atmosphere lack?
answer
oxygen
question
How was the first oxygen created?
answer
cyanobacteria using photosynthesis
question
Describe the creation of the first oxygen.
answer
1. cyanobacteria pumped oxygen into the atmosphere 2. oxygen reacted with dissolved iron 3. after reducing the dissolved iron, the oxygen was released into the atmosphere 4. oxygen formed ozone in the upper atmosphere, which shielded Earth from tissue-damaging ultraviolet light
question
How do scientists study climate change?
answer
examining the rock record around the world examining ice in Antarctica
question
What are a list of possible causes for a dramatic change in climate?
answer
volcanism meteor impacts
question
What is currently the most accepted theory behind ice ages?
answer
small changes in Earth's orbit, known as Milankovitch cycles
question
Milankovitch cycles
answer
Earth's orbit changes from more circular to more elliptical and back again these orbital changes take Earth nearer and further from the Sun, which would affect the amount of energy reaching Earth
question
The climate of the earth throughout history has always _____.
answer
fluctuated between hot and cold
question
Pangea
answer
one large landmass supercontinent interior was extremely hot and dry majority of the land was nowhere near the ocean and had very little rainfall
question
What happened because of the dry, hot climate in the interior of Pangea?
answer
erupting volcanoes spewed gases, including carbon dioxide, into the atmosphere, carbon dioxide traps heat inside (Greenhouse effect)
question
What effects did warmer temperatures have on living organisms?
answer
slows the metabolism of some creatures loss of many coal swamps amphibians and some spore-bearing plants became extinct
question
What are humans doing that can cause a drastic change in climate?
answer
burning fossil fuels that are releasing greenhouse gases
question
What effect did drastic changes in the climate at the end of the last ice age have on organisms?
answer
80% of the large mammals in North America went extinct vanishing habitats (extinction of species)
question
biostratigraphy
answer
the combination of paleontology and stratigraphy
