Exam 2 Flashcards
(109 cards)
1
Q
Fossil
A
Remains or traces of prehistoric life preserved in sedimentary rocks
2
Q
Body Fossils
A
Shells, bones, teeth, and soft tissue
3
Q
Trace Fossils
A
Tracks, trails, burrows, nests, and feces
4
Q
Conditions for fossilization
A
- Durable Skeleton
- Lived where quick burial was likely
- Avoided decay, scavenging, and metamorphism
5
Q
Types of Preservation
A
Unaltered remains, altered remains, and traces
6
Q
Unaltered Remains
A
Maintain their original structure and composition
7
Q
Types of Unaltered Remains
A
Amber, mummification, freezing, preservation in peat, and preservation in tar
8
Q
Amber
A
Lithified tree resin
9
Q
Mummification
A
Preservation of an organisms soft tissues by removing water from the body (very fragile)
10
Q
Preservation in Peat
A
- Peat forms in standing bodies of water as plant material accumulates faster than it decomposes
- Bacteria consumes the oxygen in the water and dies so that there is nothing to decompose other organisms in the water
11
Q
Preservation in Tar
A
Tar forms when oil migrates up into a standing pool on the earths surface. Animals wander in and get trapped, preserving the animals hard parts
12
Q
Altered Remains
A
Fossils that have been changed structural or chemically
13
Q
Permineralization
A
Mineral matter is added to the pores and crevices of bones, teeth, and shells after burial, which increases their structural integrity
14
Q
Recrystallization
A
Unstable compounds recrystallize to more stable compounds with no change in composition
15
Q
Replacement
A
Original skeletal material is replaced by a compound of different composition
* Pyrite (FeS2)
* Chert (SiO2)
16
Q
Carbonization
A
Volatile elements (Oxygen & Hydrogen) of organic matter vaporize leaving behind a carbon film
17
Q
Trace Fossils
A
Indirect evidence of the occurrence of life or biological activity in the sedimentary rock record
18
Q
Types of Traces
A
Molds/Casts, Tracks/Trails, Boring/Burrows, and Gastroliths
19
Q
Molds and Casts
A
- Shell buried in sediment
- Dissolution creates a mold
- Mold is filled with sediment to form a cast
20
Q
Gastrolith
A
Stomach stones
21
Q
Limitations
A
Preservation Bias and Discovery Bias
22
Q
Preservation Bias
A
The odds of life being preserved in the rock record are very small, so we only know of what was preserved
23
Q
Discovery Bias
A
We only know about the fossils that we can discover
24
Q
Organic Evolution
A
Changes through time inherited from one generation to the next
25
Theory of Inheritance of Acquired Characteristics
Inherited morphological change from physical efforts through time (Jean Baptiste de Lamarck - 1700s')
Revealed through observation of Giraffes
26
Theory of Natural Selection
Survival of the fittest (Charles Darwin, "Origin of Species" 1859)
Observed different traits of Galapagos Finches on the HMS Beagle Tour
27
Allopatric Speciation
Species arises when a small part of a population is geographically separated from its parent population
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Phyletic Gradualism
Species arises from gradual accumulation of minor changes from ancestor to descendant
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Punctuated Equillibrium
Species change little during most of history and then evolve rapidly to give rise to new species
30
Phylogeny
Evolutionary history of a group of organisms, which is limited by the amount of fossil material available
31
Divergent Evolution
Interbreeding population gives rise to diverse descendants
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Convergent Evolution
Development of similar characteristics in distantly-related organisms – like the Ichthyosaur and the Bottlenose Dolphin
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Parallel Evolution
Similar characteristics is closely related organisms – like the Ostrich and Emu
34
Cladistics
Study of relationships derived from the word clade – relationships communicated via a cladogram are based on derived characteristics
35
Clade
Group of organisms closer to each other in morphology than another group
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Extinction
State of dying out and having no living descendants
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Psuedoextinction
Species evolves into a new species so different that its ancestors can be considered extinct
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Mass Extinction
Multiple groups of organisms die out simultaneously
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Linnaean Name System
Coined by Carolus Linnaeus in the 1700s – Generic Form, Species
Based on structural similarities
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Linnaean Taxons
Kingdom, Phylum, Class, Order, Family, Genus, Species
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Species
Populations composed of individuals essentially alike in structural and functional characteristics that are potentially able to interbreed and have viable offspring
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Major Kingdoms
Monera, Protista, Fungi, Animalia, Plantae
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Kingdom Animalia Phylum's
Porifera, Cnidaria, Brachiopoda, Bryozoa, Mollusca, Arthropoda, Echinodermata, Cordota
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Kingdom Monera
Single celled, no nucleus
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Kingdom Protista
Single celled, nucleus
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Kingdom Fungi
Nucleus, nonvascular
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Kingdom Animalia
Multicellular, differentiated tissue, feed on other organisms
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Kingdom Plantae
Multicellular, vascular system
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Atom
Smallest divisible unit retaining characteristics of a specific element
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Atomic Number
Number of protons in the atomic nucleus
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Atomic Mass Units
Protons + Neutrons
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Decay
The process where the nucleus of an unstable isotope transforms into another atomic nucleus
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Isotope
Forms of the same elements with different atomic mass numbers
54
Piere and Marie Curie
Developed the ideas behind radioactive decay in 1903
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Alpha Decay
Loss of 2 protons and 2 neutrons
Atomic number -2
Atomic mass -4
56
Beta Decay
Electron emits from the electron shell causing a neutron to convert to a proton
Atomic Number +1
No change in Atomic Mass
57
Electron Capture
Proton captures an electron and converts it to a neutron
Atomic Number -1
No change in Atomic Mass
58
Half-life
Time it takes for half of the parent element to decay to the atoms of a more stable daughter element
Constant regardless of external conditions
A key ingredient in crystallized minerals is often an unstable element
59
Common isotope pairs
Uranium -> Lead
Thorium -> Lead
Rubidium -> Strontium
Potassium -> Argon
60
How does C14 form
Cosmic rays cause Nitrogen to form C14 that is absorbed by living organisms
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Proportion of C14
The proportion of C14, C13, and C12 is consistent with the atmosphere
Once an organism dies, C14 starts to decay
62
Issues with Carbon-14 Dating
1. Metamorphism causes rocks to partially melt and recrystallize which basically resets it
2. Organic matter like bacteria or smoke can skew results
3. Accuracy of laboratory analysis
63
Fission Track Dating
- Alpha decay of Uranium in igneous rocks damages the crystal leaving streaks behind
- Observing fission tracks can show the proportion of Uranium that has decayed
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Hot Origins
Comets carry portions of the sun that would cool into planets
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Cool Origins
Cold mass evolves into hot mass as it's compressed through time
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Nebular Hypothesis
The Solar Nebula (Accretion disk of dust and gas) compressed causing a nuclear reaction and the creation of a protostar
67
What does the Nebular Hypothesis explain?
- The planet order as lighter protoplanets were carried farther away from the sun
- planet star orbit as the protoplanets orbited around the nebula
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Comet
Material traveling tangentially to planets
69
Shoemaker-Levy 9
A comet in orbit of Jupiter that split into fragments because of gravitational forces. These fragments hit Jupiter and displaced gas showcasing the accretionary process
70
Mohorovicic Discontinuity
The boundary between the earths crust and mantle at which there is a drastic increase in sound energy speed
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Where does sound energy slow back down after the moho?
The asthenosphere because it is partially molten
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Layers of the earth
Lithosphere, Moho, Asthenosphere, Mesosphere, Outer core, Inner core
73
Origin of the magnetic field
The liquid outer core moves from west to east, generating a magnetic field
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Magnetic Reversal
About every 200,000-300,000 years the magnetic field switches
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Density of Continental Lithosphere
2.7g/cm^3
Similar to granite
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Density of Oceanic Lithosphere
2.9g/cm^3
Similar to basalt
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Density of Asthenosphere
3.3-5.7g/cm^3
Similar to olivine
78
Density of the Outer Core
9.9 to 12.2 g/cm³
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Density of the Inner Core
12.8 to 13.1 g/cm³
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Density/Chemical Differentiation
Process that created the internal zonation of the earth
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What is the composition of the earths core?
By supposition we know that the core is primarily composed of Iron and Nickle
82
What age are the oldest known crytals?
4.4 BY
83
What are some locations where old crystals where found?
Greenland, Australia, NW Canada, Hudson Bay, Canada, Wyoming, China
84
Outgassing Hypothesis
Lightest elements go to the surface and are emitted into the atmosphere
85
Continental Drift
F.B. Taylor - describes how the depressions between continental and oceanic plates would fill with sediment and then get compressed
86
Continental Puzzle
A. Wegner - proposed a Pangea supercontinent
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Correlating fossil records
A.L. Du Toit - fossil records suggest continents used to be connected
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H.H. Hess 1962
Discovered evidence of Continental Drift via sea floor spreading from mid-ocean ridges. Convection cells in the asthenosphere cause molten lava to rise
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Paleomagnetisism
Lava has many iron rich minerals that will orient themselves parallel to earths magnetic field when they crystalize
90
Polar Wandering
Movement of earth's poles. Originally used to explain paleomagnetism inconsistencies
91
Linear Magnetic Anomolies
Magma that forms at mid-ocean ridges will orient opposite ways as the poles switch
92
Sea floor ages
Samples of lithosphere further from the ridges are older
93
Hot Spots
Plumes in the asthenosphere push through the lithosphere creating volcanic hot spots
94
Distribution of flora and fauna
Permian - Glossopteris flora and reptiles
Mesosaurs in Africa and South America
95
Similar stratigraphic successions
Successions of Mississippian-Jurassic found globally, so similar deposition histories support Continental Drift
96
Plate Techtonics (A. Wegner)
Divergent Boundary
Convergent Boundary
Transverse (Transform) Boundary
97
What happens at convergent boundaries?
- Volcanic arcs
- Subduction and mountain building
98
Subduction
One plate sinks under the other and forms a volcanic arc
99
Ocean Arc Complex
Oceanic crust sinking beneath other oceanic crust
100
Mountain Building
Continental crust can't sink under other continental crust so mountain ranges are created
101
What does Plate Techtonics explain?
- Distribution of earthquakes around convergent and transform boundaries
- Distribution of volcanos around subduction zones
- Distribution of mountains around convergent boundaries
102
Phylum Porifera
Sponges
103
Phylum Cnidera
Jellyfish and Coral
104
Phylum Brachiopoda
Lamp shells
105
Phylum Bryozoa
Moss
106
Phylum Mollusca
Clams, Octopi, Snails
107
Phylum Arthropoda
Crustaceans, Shrimp, Insects, Spiders
108
Phylum Echinodermata
Starfish
109
Phylum Cordota
Backbones and spines (humans and mammals)
