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What are fossils?
Traces of ancient organisms formed through the fossilization processes
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What is the process fossils are formed by (main)?
Taphonomy
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Name and describe the two types of dating.
- Relative Dating – determines whether an object is older or younger than other objects.
- Chronometric (Absolute) Dating – provides an age in years (or range of years).
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What is Stratigraphy?
The study of layers of the earth
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What does the Law of Superposition state?
A lower stratum (layer) is older than a higher stratum
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What are the different types of Relative Dating?
- Stratigraphy
- Fluoride, Uranium, and Nitrogen
- Cross-dating/Biostratigraphy (Faunal Correlation)
- Pollen Analysis
- Paleomagnetism
- Seriation
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What are the different types of Chronometric Dating?
- Dendrochronology (Tree-ring Dating)
- Radiocarbon Dating (C-14 Dating)
- Potassium-Argon Dating (K-Ar)
- Uranium Series Dating
- Fission-Track Dating
- Thermoluminescence (TL)
- Optically Stimulated Luminescence (OSL)
- Electron Spin Resonance (ESR)
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What is FUN Dating?
Applied to bones to assess the amount of fluorine in ground water incorporated during fossilization; the longer the time, the more fluorine incorporated; only useful with bones found at same location
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What is Cross-dating?
Examines faunal remains (or known sediment layers) from different sites to determine the presence of certain extinct animal species whose dates are known; imited to specific geographic areas
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What is Pollen Analysis?
Examines frequencies of pollen grains from plant species to determine environmental changes at the site; limited to specific geographic areas; proper preservation of pollen in soils
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What is Paleomagnetism?
- Using the sequence of reversals of the Magnetic North & Magnetic South poles, samples of sediments containing magnetically charged particles can be dated
- These sediments are used as a “fossil compass” to date the magnetic orientation at the time-
- 0.7 mya - Now: normal northern orientation
- 2.6 - 0.7 mya: reversed southern orientation
- 3.4 - 2.6 mya: normal
- ? - 3.4 mya: reversed
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What is Seriation?
Creates a sequence (“serial order”) of tools, pottery, and other artifacts based on their shape & decoration (that change over time) and examines the popularity of these styles over time; most effective for historic sites with known dates
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What is Radiocarbon Dating?
The age of organic materials is determined based on the rate of decay of the unstable isotope Carbon-14 (C-14) into the stable form Carbon-12 (C-12); C-14 has a half-life of 5730 years, so it can be used on material that is between 300 and 50,000 years old; need well-preserved organic materials; Material has to be less than 50,000 years old
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What is Potassium-Argon Dating?
The age of volcanic material (rock & ash) is determined based on the decay of potassium (K) into argon gas (Ar); Potassium has a half-life of ~1.3 billion years, so can be used on material between 100,000 – 2 billion years old; can only be used on volcanic materials; age range has a large margin of error
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What is Uranium Series dating?
The age of limestone materials and other materials containing calcium carbonate (shell, bone, etc.) is determined based on the decay of Uranium; can be used on material between 10,000 and 500,000 years old; can only be used on calcite materials; must have careful stratigraphic sequences
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What is Fission Track dating?
The age of natural (volcanic) and man-made glass is determined based on the fissioning (splitting) of Uranium when it is heated to high temperatures; can be used on natural glass between 300,000 and 2.5 billion years old; limited to glass
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What is Thermoluminescence?
When a material (like clay or stone) is heated, minerals store energy in the form of electrons. That material continues to store more energy after it is heated as well; When heated materials are re-heated to high temperatures, these “trapped” electrons are released in the form of light; more light = older age; Thermoluminescence can be used on heated materials between 50 and 500,000 years old; The re-heating destroys the material
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What is Optically Stimulated Luminescence dating?
Measures the amount of energy trapped inside quartz due to sunlight exposure prior to burial; uses light of certain wavelengths (usually either blue, green or infrared light) that rapidly release the most light-sensitive trapped electrons from the sediment’s crystal matrix; can be used on quartz sediments between 100,000 and 500,000 years old (and potentially older).
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What is Electron Spin Resonance (ESR) dating?
Measures the amount of energy released from bones & teeth using microwave radiation (does not destroy the material); can be used on material between 1,000 and 1 million years old.
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What is Obsidian Hydration Analysis dating?
The age of volcanic glass (obsidian) is determined based on the amount of water that is absorbed at the flake edge; This technique is new and still in development, but can potentially be used to date volcanic glass up to 500,000 years old;.rate of water absorption depends on local temperatures & humidity levels, which are difficult to determine
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Name all the epochs and their timespans.
- Miocene Epoch: 23-5.3mya
- Pliocene Epoch: 5.3-2.6mya
- Pleistocene Epoch: 2.6mya-11,400ya
- Holocene Epoch: 11,400ya-present
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What are hominins?
All bipedal species in the Hominoid Superfamily
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What are distinctive characteristics of hominins?
- Earliest evidence of hominins dates to
- the end of the Miocene Epoch (~5mya).
- bipedal locomotion
- large brain size
- cultural behaviors (e.g., tool-making)
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What is the definition of culture?
Patterns of behaviors that are learned from and shared by others in a group. It is an innovative adaptive strategy involving cognitive, political, & socio-economic aspects.
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What does environmental determinism do?
links simple environmental changesdirectly to a major evolutionary shift in an organism. Tends to oversimplify the evolutionary process.
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What are the advantages of bipedalism?
- Frees hands (for carrying objects, making and using tools, gathering seeds and nuts, feeding from bushes, and hunting)
- Thermoregulation
- Visual Surveillance
- Efficient means of covering long distances and provisioning by males of females with dependents
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What are the differences in skulls between apes and humans?
- Apes:
- Sagittal Crest
- More pronounced snout
- Smaller cranial capacity
- Humans:
- No Sagittal Crest
- Flat face & nose
- Larger cranial capacity
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