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ANT 394: Advanced Topics In human Evolution > Exam 1 > Flashcards

Exam 1 Flashcards

0
Q

What is the geographic time scale used to describe the timing of events in the earth’s history? What does each component represent?

A

Era-? Period-? Epoch-?

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1
Q

How old is the earth?

A

4.6 billion years old

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2
Q

List the Epochs of the Cenozoic Era. (Hint: Please Eat Only Mom’s Pizza Pies Hot)

A

Paleocene Eocene Oligocene Miocene Pliocene Pleistocene Holocene

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4
Q

What major events happened during the Paleocene Epoch? How many years ago did it begin and how long did it last?

A

Major events: -Proprimates (Plesiadapiforms) 65.5 mya 65-54 Million Years Ago

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5
Q

What major events occurred during the Eocene Epoch? How many years ago did it begin and how many years did it last?

A

Major Events: -Appearance of Euprimates (modern aspect); True primates that share the full suite of characteristics AKA: First True Monkeys (35-40 mya) 54-34 Million Years Ago

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6
Q

What are the characteristics of the primate anatomy that anthropologists look for in the fossil record?

A
  1. Complete postorbital bar 2. Petrosal bulla 3. Forward facing eyes, stereoscopic vision 4. Generalized teeth/unspecialized molars 4. Generalized body plan/unspecialized limbs 5. Reduced prognathism 6. Enhanced vision 7. Reduced olfaction, smaller olfactory bulbs 8. Grasping hands & feet with opposable hallux (big toe) and/or pallux (thumb) 9. Flat nails, tactile finger pads 10. Enlarged brains relative to body size, elaborate neocortex
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7
Q

What major events happened during the Oligocene Epoch? How many years ago did it begin and how long did it last?

A

Major Events: -First Anthopoids/higher primates (monkeys) 34-23 Million Years Ago

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8
Q

What major events happened during the Miocene Epoch? How many years ago did it begin and how long did it last?

A

Major Events: -Appearance of first Hominoids (Apes) -Apes dominated during this epoch (20-17 mya) …..Apes started going extinct at the boundary between the Miocene and Pliocene epochs. First Hominin; this hominin was bipedal (5-7 mya) 23-5 Million Years Ago

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9
Q

What major events happened during the Pliocene Epoch? How many years ago did it begin and how long did it last?

A

Major Events: -The beginning of our lineage: First member of genus Homo (2.5 mya) 5-1.8 Million Years Ago

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10
Q

What major events happened during the Pleistocene Epoch? How many years ago did it begin and how long did it last?

A

Major Events: -Increase in brain size (1.8 mya) at boundary between pliocene and pleistocene -First Anatomically Modern Humans (200 kya) 1.8 mya-10 kya

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11
Q

What major events happened during the Holocene Epoch? How many years ago did it begin and how long did it last?

A

Major Events: Origins of agriculture and civilization -First Farmers –> First Cities 10 kya-present

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12
Q

What are fossils?

A

Fossils are biological material that have been chemically changed (mineralized) into rock.

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13
Q

Under what condition can DNA be extracted from fossils?

A

At least some biological material must be remaining in the fossil.

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14
Q

What is the name of the specialization in paleontology that studies what happens to an organism’s remains after death? In other words, it asks the question, “what happens to the the individual in the environment between the time when that person died and when the person becomes fossilized?” ex. eaten by a predator, carried downstream, torn apart by a vulture, etc.

A

Taphonomy

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15
Q

Taphonomy describes the circumstances that are necessary for fossilization to occur. What type of environment is necessary for fossilization to occur?

A

An anoxic environment where decomposition is limited ***An organism will not fossilize if it dies in a rainforest, because moisture aids in decomposition.

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16
Q

What are the two best substrates for fossilization? What can chemical segments of bone tell us?

A
  1. Sedimentary Rock 2. Volcanic Rock/Ash Chemical segments of bone can tell us things such as what the individual was eating or environmental conditions
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17
Q

Recognition of what limitations is critical in interpreting the fossil record?

A
  1. The fossil records present a “snapshot” of life in the past…representation is important. 2. Fossilization depends on environmental conditions; there are gaps in the fossil record, as fossilization is more apt to occur in particular regions and time periods ex. The best preservation of human remains is in eastern and southern parts of Africa after 4 mya
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18
Q

Any geological objects that can be arranged in a sequence from older to younger are called ______

A

Stratigraphic Units

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19
Q

What are the three types of stratigraphic units?

A
  1. rock-stratigraphic units (lithostratigraphy): Bed>member>formation 2. biostratigraphic units: ex. pig teeth; give us relative date 3. Chronostratigraphic units
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20
Q

List and describe the two methods fossil dating methods.

A
  1. Relative = position of fossil in relation to other better understood specimens (ie., mice) Stratigraphy is important 2. Numerical = relies on constant processes well known to physics, chemistry, and biology to determine age in years
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21
Q

Another specialization in paleoanthropology looks at the stratigraphic units (the soil and rock deposits, which create the layers of different sediment building up over time. This member of the paleoanthropology team carefully maps these layers. What is this specialization called?

A

Geologist

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22
Q

List the three forms of Relative Dating Methods.

A
  1. Fluorine Method 2. Stratigraphy 3. Biostratigraphic Dating
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23
Q

Describe the Fluorine Method. What is one limitation of the fluorine method?

A

Fluorine dating reveals the relative ages of fossil bones at the SAME SITE. Bones absorb fluorine from ground water. Therefore, fossils that have been in the soil longer will have larger amounts of fluorine. The fluorine method can test whether bones were buried contemporaneously (at the same time) Limitation: cannot compare relative age across sites because different locations have different amounts of fluorine

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24
Q

What are the basic assumptions of Stratigraphy?

A
  1. Deeper layers are older than more shallow levels 2. Fossils found in deeper layers are older than more shallow layers 3. There is no movement of layers
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25
Q

What are the potential pitfalls of stratigraphy?

A
  1. Non-horizontal alignment of sediment 2. Movement of fossil material by burrowing animals 3. Layers may have moved due to geologic activity
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26
Q

True or False. Only one dating method is used to date fossils

A

False

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27
Q

Microtine (Mouse), horse, pig, and elephant teeth would be used for what type of relative dating method?

A

Biostratigraphy

28
Q

What information must you have to use the biostratigraphic dating method?

A

You must know the evolutionary history of the reference organism

29
Q

Isotopic (Radiometric) Methods are considered “Numerical” dating methods. On what do these methods rely?

A

Radiometric methods rely on the constant decay of radioactive isotopes into more stable forms.

30
Q

What are the limitations of Isotopic (radiometric) methods?

A

Limitations: 1. Require specific types of bed material (ie., volcanic rock) 2. Resolution is limited to specific time periods due to rates of decay; once the isotope transforms 100% in to the new isotope, it can’t be dated

31
Q

What is meant by the term “Half-Life”?

A

1/2 of the original isotope is gone and had transformed into the new isotope. Used to callibrate the age of the biological material

32
Q

List the four types of Isotopic (radiometric) methods that are important in Paleoanthropology.

A
  1. Radiopotassium (Potassium/Argon) Dating 2. Fission-track Dating 3. Uranium-series Method 4. Radiocarbon Method
33
Q

Radiopotassium (Potassium/Argon) Dating is used to determine the age of biological material found in what substrate? How does it work? How old must the material/sample be?

A

Substrate: Volcanic ash, lava ***High temps reset clock on 40K which begins to decay into 40AR when cooled Sample Age Requirement: Used for samples older than 500 ky old.

34
Q

Fission-Track Dating looks at what two substrates? At what type of event does it look? How is the date of that event determined? What is one limitation of this method?

A

Substrates: Glasses and Minerals Type of event: cooling event (vs hot event that takes place in lava) Date of last cooling event determined by: ratio of DENSITY OF TRACKS (fission of uranium-238) and the amount of uranium-238 in the sample Limitation: The fossil must be very old for this method to work.

35
Q

The 40AR/39AR Variant of Potassium/Argon Dating (called argon argon dating) was used to date Ardipithicus ramidus at Aramis, Middle Awash, Ethiopia to 4.4 mya. What makes this method more precise than Radiopotassium Dating?

A

It is able to date biological material based on dates of single crystals.

36
Q

Fission-Track Dating was used to validate radiopotassium dates at East African hominin sites.

A

That’s a fact.

37
Q

Uranium Series Dating is most useful for dating _____.

Uranium Series Dating has many sources of error when used to date bone. What biological material yields more reliable results when using this method?

What is one limitation of this method?

A

Sea and lake bottom sediments; dates climate events

Corals are more reliable.

Limitation: It must be validated by other methods because it has many sources of error.

38
Q

Animals Die–>metabolism ceases–>tissues stop incorporating 14C–>14C decays into nitrogen…..blah blah half life crap

A

Radiocarbon (Carbon-14) Dating

39
Q

What are the limitations of Radiocarbon Dating?

A

Can only go back 40,000 years, so dates have to be calibrated and often underestimate actual date

40
Q

Luminescence and Electron Spin Resonance was created from the basis that radioactive isotopes cause electrons to accumulate defects within crystalline substances.

What does this method require?

What is it mainly applied to, and for what is it used?

What is the age range of biological material that be examine using this method?

A

Requirement: trapped electrons

Applied to: Dental Enamel

Used to: date modern people in Israel (from flint) to 120-90kya

Age Range: variable from a few to 100 kya

41
Q

What form of analysis was useful for tracing retreat of the last Glaciation ice sheet (“ice age”)?

Hints: analyses lake floor layers of sediments and has a range of 8,000-10,000 years.

A

Varve Analysis

42
Q

What is the name of the nonradiometric numeric dating method that traces global shifts in polarity and is useful for bracketing sites in time range when they can’t be stated directly

A

Paleomagnetic Stratigraphy

43
Q

Fossilized vegetation includes fossil plants, pollens, and plant impressions.

  1. What does fossilized vegetation disclose?
  2. In what type of site/environment are plant fossils found?
A
  1. vegetation discloses what a local environment was like at the time a site formed.
  2. Plant fossils can be abundant in damp sites (peat bogs) or in fine-grained sediments. ***Wet environments are not as much of a detriment to plants as they are to animals in terms of fossilization. Moisture does not speed up the process
44
Q

What is a useful technique in reconstructing past vegetation?

A

Stable Carbon Isotope Ratios

Carbon isotopes differentiate between various photosynthetic pathways used by trees and shrubs, grasses, or arid-adapted plants

Carbon isotopes can be recovered from ancient soils (paleosols) and biological material (bones, teeth, hair)

45
Q

Natural Selection is a mechanism to explain how evolution occurred; it is one of the forces of evolution.

Describe how this force works

A

Individuals are differentially reproduced based on the heritable differences between them. (“Differential Reproductive Success”)

Fitness is determined by the sum of environmental forces or pressures.

It is non-random in that it is survival of the fittest

46
Q

Define the term ‘Fitness’.

A

Individuals’ ability to survive and produce offspring who themselves survive and reproduce.

47
Q

What 3 conditions must be met in order for a trait to be considered the result of natural selection?

A
  1. Individuals within a breeding population must show variation in a trait.
  2. The trait must be heritable.
  3. There is differential reproductive success.
48
Q

What is evolution?

Does it happen at the individual level or the population level?

A

Evolution is biological change over time.

Evolution occurs at the population level. (Natural Selection happens at the individual level)

49
Q

What is an ‘Adaptation’?

A

A trait that is specially suited for a particular function in a particular environment; subject to natural selection; the result of non-random elimination

50
Q

Adapations consist of evolved ________ traits that increase an organism’s _______________.

A

phenotypic; reproductive success (“fitness”)

51
Q

The diversification of one founding species into multiple species and niches is called __________.

Hint: Darwin’s observations of finches at the Galapagos Islands led to this concept.

A

Adaptive Radiation

52
Q

Adaptive radiation of Apes occurred during what Epoch?

A

Miocene

53
Q

Several “Clues” led Darwin to his theory of Natural Selection. List and describe the three most influencial clues and the scientists/experiences from which these clues originated.

A
  1. Uniformitarianism-The geological processes that drive the natural world today are the same as those that drove it in the past.
    • Scientist-Lyell (1797-1875)
      • The earth changes slowly and gradually
      • It is important to study ancient changes in the Earth’s history
      • The Earth is much older than previously thought
    • From this, Darwin reasoned that the earth was old enough to allow for speciation via natural selection
  2. Economic Theory-Populations grow exponentially, while resources grow arithmetically–>results in a struggle for existence (In other words, when a population outstrips its resources, it will crash).
    • Thomas Malthus (1766-1834)
  3. Artificial Selection - Ex. Animal Husbandry
    • Darwin was a pidgeon breeder.
54
Q

What is Pleiotropism (morphological)?

Provide an example.

A

Changes in one morphological trait influences the expression of other traits

Example: Change in the evolution of the human jaw resulted in the ‘chin’

55
Q

phyletic gradualism is also known as _________.

A

Adaptive Radiation

The adaptive radiation/phyletic gradualism model assumes *anagenesis * or gradual change along separate branches of the evolutionary tree.

56
Q

Does punctuated equilibrium emphasize cladogenesis or anagenesis?

A

Punctuated equilibrium strongly emphasizes on branching or Cladogenesis (the formation of branches or clades.)

57
Q

In the __________ model, the driving force behind speciation remains natural selection, but its intensity varies over time, and it is episodically intense. Episodic climatic change is probably the most fundamental force, and in combination with mountain building, sea level changes, and other major geologic events, it could fragment a widespread species into isolated populations and thus hasten their tendency to diverge genetically.

A

Punctuated equilibrium

58
Q
  • Termed by Eldredge and Gould (1972)
  • True evolutionary innovations appear and spread suddenly and infrequently
  • Often sparked by major climatic or environmental shifts
  • Emphasizes Cladogenesis
A

Punctuated Equilibrium

59
Q

What is a Reproductive Isolating Mechanism?

A

Any factor preventing a male and female of two different species from hybridizing

60
Q

Premating RIM Def + examples

A

.

61
Q

Postmating RIM def + ex.

A

.

62
Q

micro vs macro evolution

A

.

63
Q

3 types of geographic speciation

A

.

64
Q
A
65
Q

One problem with laskdjf;sldkjf

A

.

ANT 394: Advanced Topics In human Evolution (1 decks)

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