3:57 PM Geological and climate changes and vertebrate evolution Flashcards

1
Q

how old is the earth? what is geological time?

A

ime of the physical formation and development of the earth
The earth is 4.5 to 5 billion years old - life would have been there 4.5 to 5 bya- hot magma, internal mass heats up and fragmentation occurs, pangea splits/breaks

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2
Q

what are continental drifts?

A

○ Continental drifts - broken blocks moving on the hot magma (crust is the thinnest of the three and the coldest) - coalescence and fragmentation again (build break, build break, etc)

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3
Q

what are the units of time? - read when each one happened

A

○ Eons - the largest subdivision
§ Eras
□ Periods
® Epochs

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4
Q

life during pre cambrian vs mesozoic. when did chordates appear?

A
  • Earth came with hot molten magma at the beginning - only minute archaea and bacteria) simple life existed - pre Cambrian
    • Mesozoic - greater diversity of life
    • Chordates happens during early cambrian
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5
Q

describe pre cambrian and cambrian periods

A
  • Precambrian (4.5 bya) - first continental masses (Pangea starts breaks apart) creates lots of environmental change that will precipitate different life forms (archaea and bacteria at this point)
    • Cambrian (542 Mya)- first vertebrates
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6
Q

describe devonian and late devonian

A
  • Devonian (416 Mya) - anthropods and first fish diversity appear
    • Late devonian - first tetrapods (cilicads) , four limbs start appearing
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7
Q

describe carboniferous, triassic, and jurassic periods

A
  • Carboniferous (359 Mya) - radiation of reptiles
    • Triassic (251 mya) - first mammals; dry interior continents, more terrestrial
    • Jurassic (201.6 mya) - dinosaurs and birds radiate
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8
Q

define continental drift

A

• Continental drift - the movement of continental blocks on the mantle of the earth, can move towards or away from each other

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9
Q

define plates and plate techtonics. what do they result in? what is coalessence?

A

• Plates- masses of crusts that move independently of adjacent plates (dried as exposed when pangea separated)
• Plate tectonics - a process involving interactions of moving crustal plates
○ Results in major structural features of the earth
○ Concept essentially same as continental drift but focuses on the plates below the continents
process of fragmentation - coalescence - fragmentation
• As well, the positions of the continents in relation to the equator have also changed continuously
• Central spots may change
• Coalescence is coming together - plates collide

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10
Q

what does pangea break into? when?

A

• Some move further up, some move further down - those moving south will eventually be gondwana, and those moving north from the equator will be the laurasia. Pangea is before they separated
paleozoic - pangea
mesozoic - laurassia and gondwanna
cenozoic- all continents we have now - asia is eurassia

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11
Q

describe early paleozoic climate. during silurian? late devonian? mid carboniferous to mid permian?

A

• Early Paleozoic
○ O2 levels lower than current level of 21% (now 18%!!!)
○ CO2 higher - probable greenhouse effect
○ As oxygen rises - setting up a stage for life to develop
• O2 levels rose during Silurian - cyanobacteria photosynthesizing (???)
• Glaciation during late Devonian - periods of glaciation are associated with periods of cooling
○ Radiation of land plants - diversification, expansion
§ Sharp decrease in CO2 concentration
○ Much of gondwana covered with ice from mid-carboniferous to mid-Permian
○ Most vertebrates in the equatorial

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12
Q

what does continental drift impact?

A

Air temp, wind and air currents, precip. patterns, ocean currents, sea levels, formation of mountain ranges

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13
Q

how does continental drift impact air temps

A
  • Small vs large land masses - the smaller the mass the easier it is to heat up, the larger it is the longer for temperature change to turn over
    • Interior vs exterior land masses - interior is drier - greater rate of evaporation
    • Less temperature fluctuation on interior (double check!!!)
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14
Q

how does continental drift impact wind and air currents

A
  • Change with temperature over land and water
    • Affect the life forms and change as temperature changes
    • Changes in the size and position of land masses will affect the temp and wind pattern of airmasses
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15
Q

how does continental drift impact precip patterns

A
  1. Precipitation patterns
    • Change with temperature and wind
    Mountain building forms rain shadows - will eventually drop down as precip.
    • Affected by wind pattern and evaporation rates
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16
Q

how does continental drift impact ocean currents

A
  • Ocean currents and flow patterns change with movement and position of land masses
    • Air temperature affected by warm and cold currents
    • Ex. The arctic ocean is currently isolated from other ocean and does not receive warm water from the south because of the position and size of the land masses
17
Q

how does continental drift impact sea levels

A
  • Changes with sea floor spreading and melting of the polar ice caps and glaciers
    • Late Mesozoic (245 mya) and early Cenozoic (65 mya) - many epicontinental seas (sea extending within the margins of a continent)
    • Flooded large parts of continental interiors - especially north America and Eurasia
    • More maritime climates will occur in continental interiors - during these times, a continental climate will prevail ( will become drier with less stable air temperature)
18
Q

how does continental drift impact formation of mountain ranges

A
  • Results when plates collide
    • Affects air currents, precipitation patterns, animal and plant dispersal, and animal movement - serves as a barrier - one side may have more favorable conditions for life than the other
    • Affects air temperature
    • Will affect life forms
    • Life forms will grow with more precipitation
19
Q

how does continental drift impact geographic isolation

A
  • Due to changing size, number, and position of the land masses and mountain formation
    • Great effects on speciation and extinction - organisms may not be free to interact
    • Zoography - the study of the diversity and distribution of animal taxa
    • Zoogeography - life form, geographic distribution of animals
    • Isolation - different species evolve, extinction, creation of new species because of the environmental condition
    • Speciation will occur
20
Q

how does continental drift impact bolide impacts

A

• Solar system - Oort cloud interactions with large asteroids, meteoroids, and comets have periodically modified the stability of ecosystems and ‘impacted’ the extinction of the majority of animal lineages.