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What are fossils?
Traces of ancient organisms formed through the fossilization processes
What is the process fossils are formed by (main)?
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).
What is Stratigraphy?
The study of layers of the earth
What does the Law of Superposition state?
A lower stratum (layer) is older than a higher stratum
What are the different types of Relative Dating?
- Fluoride, Uranium, and Nitrogen
- Cross-dating/Biostratigraphy (Faunal Correlation)
- Pollen Analysis
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)
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
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
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
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
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
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
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
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
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
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
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).
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.
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
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
What are hominins?
All bipedal species in the Hominoid Superfamily
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)
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.
What does environmental determinism do?
links simple environmental changesdirectly to a major evolutionary shift in an organism. Tends to oversimplify the evolutionary process.
What are the advantages of bipedalism?
- Frees hands (for carrying objects, making and using tools, gathering seeds and nuts, feeding from bushes, and hunting)
- Visual Surveillance
- Efficient means of covering long distances and provisioning by males of females with dependents
What are the differences in skulls between apes and humans?
- Sagittal Crest
- More pronounced snout
- Smaller cranial capacity
- No Sagittal Crest
- Flat face & nose
- Larger cranial capacity