ESS197 final exam Flashcards
the three parts of the earth are:
core, mantle, crust.
describe the core.
- made out of two main parts, a solid inner core and a liquid outer core
- the center of our planet
- up to 55 000 C
what is the outer core of the earth made of?
mostly nickel, iron, and molten rock.
describe the mantle.
- between the core and the crust.
- about 2900 km thick.
- the top part of the mantle and the crust form the lithosphere.
what is the mantle made of?
dense, iron and magnesium-rich rock.
describe the crust.
- the top, outermost layer of the earth.
- two types of crust, oceanic and continental.
describe oceanic crust.
denser and thinner; made mostly out of basalt.
describe continental crust.
less dense and thicker; made mostly out of granite.
is continental crust thicker or thinner than oceanic crust?
thicker.
is continental crust more or less dense than oceanic crust?
less.
geologic time scale is define as:
a representation of time on the geological record.
the four eons, in order from oldest to youngest, are:
hadean, archean, proterozoic, and phanerozoic.
the three eras in the phanerozoic eon, from oldest to youngest, are:
paleozoic, mesozoic, and cenozoic.
the periods in the paleozoic era, from oldest to youngest, are:
cambrian, ordovician, silurian, devonian, carboniferous, and permian.
the periods in the mesozoic era, from oldest to youngest, are:
triassic, jurassic, and cretateous.
the periods in the cenozoic era, from oldest to youngest, are:
tertiary and quaternary.
how many periods are there?
eleven.
the cambrian period is known for:
invertebrate animals and brachiopods.
the ordovician period is known for:
early bony fish.
the silurian period is known for:
earliest land animals.
the devonian period is known for:
first seed plants.
the carboniferous period is known for:
first insects.
the permian period is known for:
first reptiles.
the triassic period is known for:
first dinosaurs.
the jurrasic period is known for:
first birds.
the cretaceous period is known for:
modern seed plants, dinosaurs.
the tertiary period is known for:
rise in mammals.
the quaternary period is known for:
the age of the humans.
the theory of plate tectonics states that:
earth’s lithosphere is divided into multiple plates that move around and make contact with each other.
the rock cycle is:
a series of processes that transform one type of rock into another.
the three types of rock in the rock cycle are:
igneous, metamorphic, and sedimentary.
igneous rock is:
made from the solidification of magma or lava.
metamorphic rock is:
already existing rock altered via heat, pressure, or chemical changes that do not melt the rock.
sedimentary rock is:
rock created from the accumulation, computation, and cementation of mineral and organic particles.
relative dating:
describing the relative order of past events without determining a numerical age.
absolute dating:
the process of determining age via radiometric techniques.
define fossil.
the preserved remains of plants + animals in sedimentary rock.
fossils are important because:
they provide important evidence for evolution, and information regarding past environments. can also be used to date rocks.
the two categories of fossils are:
fossilized body parts and fossilized traces.
define index fossil.
a fossil that is characteristic of a particular span of geologic time or enviroment.
to be an index fossil, a fossil must be:
- abundant
- represent a short paleontological range
- have a widespread geographic distribution.
define mass extinction.
a short period in geological time in which a high percentage of biodiversity or distinct species dies out.
how many mass extinction events have occured?
five.
the five mass extinctions, from oldest to youngest, are:
- the ordovician-silurian extinction
- the late devonian extinction
- the permian-triassic extinction
- the triassic-jurrasic extinction
- the cretaceous-tertiary extinction
when did the ordovician-silurian extinction occur, what was the death rate, and what were the causes?
- 440 million years ago.
- death rate of around 85% of al animal species on earth.
- causes: climate change.
when did the late devonian extinction occur, what was the death rate, and what were the causes?
- 365 million years ago.
- death rate of around 70-80% of species in marine communities.
- causes: lack of aquatic oxygen circulation, decrease of CO2 in the atmosphere, and global cooling.
what was the late devonian extinction known as?
The Age of the Fishes.
index fossils of the late devonian extinction:
trilobites.
when did the permian-triassic extinction occur, what was the death rate, and what were the causes?
- 250 million years ago.
- death rate of 99%.
- causes: mass volcanism, rise in ocean + atmospheric temperatures.
index fossils are the permian-triassic extinction:
lystrosaurus, conodonts.
when did the triassic-jurrasic extinction occur, what was the death rate, and what were the causes?
- 210 million years ago.
death rate of around 76%. - causes: mass volcanism, climate change (more CO2 in atmosphere, causing temps. to go up)
when did the cretaceous-tertiary extinction occur, what was the death rate, and what were the causes?
- 65 million years ago.
- death rate approximately 75% of all life on earth.
- causes: mass volcanism, asteroid impact.
- dinosaurs were the dominant land animals during this time.
index fossils of the cretaceous-tertiary extinction:
- coccolithophores, dinosaurs.
what was the biggest mass extinction ever recorded?
the permian-triassic extinction.
the Quaternary Extinction Event:
- not a mass extinction.
- the extinctions of megafauna all over the world.
- causes: climate change and human hunting.
- 50 000 to 10 000 years ago.
