Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Paleo 200 > Chapter 9 > Flashcards

Chapter 9 Flashcards

1
Q

What is the principle of Superposition

A

-the tendency for rock layers to be chronologically stacked

  • there are exceptions
  • > as igneous rocks that form from volcanic activity can vertically cut through horizontally arranged layers of locks
  • > mountains building events may tilt, fold and even flip rock layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is stratigtaphy

A

-it is the science of using the arrangement and composition of rock layers to interpret geological history

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a formation

A
  • A LARGE UNINTERRUPTED SEQUENCE OF ROCK THAT IS made up of multiple layers
  • > these layers all share similar properties
  • > properties include mineral composition and average sediment grain size

-note these sequences of rock formed under similar conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does a changing formation indicate

A

-that a large scale change occurred in the environment where the rocks were being deposited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Does the principle of superposition allow to determine the absolute age of the rocks

A
  • no
  • > it allows to determine the relative age
  • > that is how old one layer is in relative to another
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you age rocks in absolute terms

A
  • by using a technique called radiometric dating
  • > all matter is composed of chemical elements
  • > some of these chemical elements may exist as isotopes
  • some isotopes are unstable and will undergo radioactive decay
  • > where the energy is released and a new atom with a different compositon of particles results
  • > these resulting atoms with different particle compositions are called the decay products
  • > when a new rock forms, it has a ratio of isotopes and decay products that matches the environment
  • using a mass spectrometer, it is possible to measure the isotope ratio of a rock
  • > this ratio can tell you how long ago the rock formed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Can sedimentary rocks be radiometrically dated

A
  • no

- >because they are made of sediments that had already been undergoing radioactive decay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can igneous rocks be radiometrically dated

A
  • yes

- >because they are formed anew

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can you tell the age of fossils

A
  • by combining radiometric dating and the principle of superposition
  • if sedimentary rocks that contain fossils are horizontally deposited between two igneous rocks
  • > then the dating of the igneous rocks above the sedimentary layers will tell us what the age of fossils must be older than
  • > dating the igneous rocks below the sedimentary layer will tell us what the age of the fossils are younger than

-so this process gives an overall bracket of the age of fossils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the geologic time scale

A
  • it is a standardized series of chronological divisions that brings together the Earth’s history into discrete named units
  • > the largest units in the time scale are Eons
  • > followed by Eras, Periods and Epochs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the Haden Eon

A
  • it was from 4.6 billion to 4 billion years ago
  • by the beginning of this eon, the rest of the unverse was already over nine billion years old
  • the surface of the Earth at this time was partially molten and with volcanic activity widespread
  • at roughly 4.5 billion years ago, the Earth collided with another planetoid
  • > this collision ejected a large mass of debris
  • > which was held in Earth’s orbit and eventually became the moon
  • by the end of this eon
  • > the earth had cooled and the oceans covered most of the surface

-note the oldest rocks on earth have been dated at only about 4.4 billion years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the Archean eon(4 to 2.5 billion years ago)

A
  • the oldest fossils come from the Archaean eon
  • these fossils are simple single-celled organisms
  • > more advanced forms later evolved, including cyanobacteria
  • cyanobacteria were photosynthetic and eventually produced a large amount of oxygen gas
  • > this gas became concentrated in the Earth’s atmosphere
  • some cyanobacteria formed stromalites
  • > which look like lumpy stones
  • > but when you cut them in half, you see the layers that were created as the cyanobacteria secreted sticky films that trapped particles of sediment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the Proterozoic eon

A
  1. 5 billion to 541 million years ago
    - at approximately 1.7 billion years, the first multicellular organisms evolved
    - the time span from 630 to 542 million years ago is known as the Ediacaran period
    - >during this time, large forms of life with some harder parts evolved, including the fist animal life
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the Phanerozoic eon

A

541 to 0 million years ago

  • it is subdivived into three eras
  • > these eras are subdivided into numerous periods
  • it is during this time that animal life rapidly evolved into multitude of diverse forms
  • > including dinosaurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the Palezoic era

A

541 million to 252 million years ago

  • at the start of this ear
  • > animal life was restricted to primitive invertebrates living in the oceans
  • > great forests covered the land and teamed with reptiles, amphibians and insects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the Cambrian Period

A

541 to 485 million years ago

  • it marks the beginning of the dramatic diversification of aquatic animal life
  • > referred to as the Cambrian explosion
  • > sponges, molluscs, worms and many kind of anthropods evolved at this time
17
Q

Did Anomalocaris, Opabinia and Pikaia come from the Cambrian Period

A

-yes

18
Q

Describe the Ordovician Period

A
  • it occured from 485 to 443 million years ago
  • global sea levels were high
  • life in the oceans continued to diversify
  • > with fish increasingly becoming the dominant large aquatic animals
19
Q

Describe the Silurian Period

A
  • it occurred from 443 to 419 million years ago
  • until this point, fish had not yet evolved jaws
  • with the evolution of jaws, came large predatory fish
  • primitive plant life began to flourish on land
20
Q

Describe the Carbineferous Period

A
  • 359 to 299 million years ago
  • amphibians were widespread in the abundant swamps
  • reptiles, the first amniotes evolved
  • much of the coal that is mined today is formed from the rotting plants of Carbiniferous swamps
21
Q

Describe the Permina Period

A
  • continents collided together and formed a single super continent called Pangeea
  • reptiled involved into three main lineages
  • > anapsids(would become turtles)
  • > synapsids(go on to evolve mammals)
  • > diapsids(evolve into lizards, snakes, crocodiles and dinosaurs)
  • many of the terrestrial rocks from this period of time represent dry, desert environments
22
Q

Describe the Mesozoic Era

A
  • 252 million to 66 million years ago
  • referred to as the age of dinosaurs
  • ,any kind of marine reptiles evolve, including the ichthyousars, plesiosaurs and mosasaurs
  • the first flowering plants evolved towards the end of the Mesozoic
23
Q

Describe the Cenozoic Era

A
  • it is 66 to 0 million years ago
  • it is often referred to as the age of mammals
  • the extinction of dinosaurs allowed mammals to evolve into large forms
  • > note mammals had been around since the Triassic
24
Q

Describe the Paleogene Period

A
  • 66 to 23 million years ago
  • global temperatures began to cool
  • mammals diversified into a variety of new forms
  • > including primates, bats and whales
  • > birds also diversified
25
Q

Describe the Neogene Period

A
  • 23 to 2.6 million years ago
  • global temperatures continued to cool
  • the first hominids evolved in Africa
26
Q

Describe the Quaternary Period

A
  • 2.6 million to 0 million years ago
  • the earth experienced several large events, such as the ice age
  • humans first evolved
27
Q

When did the Triassic Period begin

A
  • from 252 to 201 million years ago
  • during the first ten million years of the Triassic, life gradually recovered from the mass extinction that occured at the end of the Permian
  • the first mammals and dinosaurs evolved during the later portion of the Triassic
  • > so did the first pterosaurs(first vertebrates to fly)
  • Pangaea began to break apart
28
Q

Do many dinosaurs from the Triassic period look similar

A
  • yes
  • the first representatives
  • > the ornithiscians, theropods and sauropodomorphs were all mostly small and bipedal
29
Q

Did the ichthyosaurs evolved during the Triassic

A
  • yes
  • > their name means fish lizard
  • > they are a group fo reptiles that took on a fish-like lifestyle
  • their ancestors were terrestrial reptiles
  • > but found success by making an evolutionary return to the water
  • they had paddle like front and hind limbs
  • > a finned tail and a shark-like dorsal fin
  • > their long snouts resembled those of dolphins and were filled with conical teeth
  • > they did not have giills and needed to come to the surface to breath
30
Q

Did the plesiosaurs evolve during the Triassic period

A
  • yes
  • > they had large chests and torsos
  • > broad paddle-shaped limbs
  • > and relatively short tails
  • in front of their shoulders, there was huge variation
  • > some had short necks and huge jaws
  • > others had elongated necks and small heads
31
Q

Did the pterosaurs evolved during the Triassic

A
  • yes
  • > they are commonly called pterodactyls
  • > they are closer relatives of dinosaurs who branched off from the reptilian family tree at roughly the same time in the Triassic that dinosaurs did
  • they were the first vertebrates to fly
  • they have membranous wings supported by a single extremely elongated finger
32
Q

Which group did eary pterosaurs belong to

A
  • they belonged to a group called rhamphorhybchoids

- >that were common in the Late Triassic and throughout the Jurassic

33
Q

Was Jurassic Period the peak of sauropod diversity

A
  • yes
  • Jurassic period was from 201 to 145 million years
  • > sauropods were very diverse and the dominant terrestrial herbivores
34
Q

Describe the general characteristic of organisms that formed during the Jurassic

A
  • ornithopods were common
  • non-coelurosaurian theropods(Allosaurus) were dominant terrestrial carnivores
  • the stegosaurs are almost completely restricted to the Jurassic
  • the first ankylosaurs, ornithopods and ceratopsians appear at this time
  • > but they are not very abundant or diverse

-the first birds, including Archaeopteryx evolved ruing the Jurassic

35
Q

What happened to rhamphorhynchoid pretosaurs during the Jurassic

A
  • they gave rise to a new pterosaur group

- >called the pterodactyloids

Paleo 200 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions