Engines of the Planet Lecture Flashcards
What has been the most important factor in causing major, long-term changes in the patterns of organism distribution? (over geological time)
the movement of continents! (Plate tectonics)
the movement of land masses across latitude bands resulted in land masses lying in different ____ regions
climatic
= huge impact on organisms on the land masses
Tectonic plate movement is responsible for:
- formation of: (list 3)
- destruction of: (list 1)
formation of mountain chains, volcanic islands, and epeiric or epicontinental seas
destruction of epeiric/ epicontinental seas as well
How do epeiric/ epicontinental seas form? What are 2 implications of them?
- sea levels rise and oceans flood continental plates
- acted as barriers to terrestrial organisms, sub-dividing the landmasses into smaller regions
- provided a habitat in which diverse marine life could thrive
By the end of the Cambrian, ___ fragments had broken away from a supercontinent (Rodinia) that formed over 1 billion years ago
3
when did the ancient continents consolidate?
during the carboniferous + permian periods of the paleozoic era
The consolidation of the ancient continents resulted in the formation of _____ _______, and eventually, _______…
mountain ranges
the supercontinent Pangaea and the global Panthalassic ocean
What are the implications of having one supercontinent and a global ocean?
great connectivity and exchange b/w terrestrial and marine biotas
- eg. pangaea and the global panthalassic ocean
separation of the Laurasian and Gondwanan continents during the mesozoic era began as a ____ ____ and expansion of the ___ ___.
What did this lead to?
rift valley
Atlantic sea
This separation eventually led to the opening of the circum-equatorial seaway
The onset of the cenozoic era was marked by:
the impact of the chicxulub asteroid and mass extinctions, which were followed by diversification of mammals and other surviving lineages
What resulted in the uplift of the Himalayas?
the continents continued to drift apart, sometimes colliding with isolated landmasses
- this resulted in the rapid northward lifting of India and its eventual impact with Asia, caused the uplift of the Himalayas
Continued drifting of the continents during the Neogene and Quaternary periods resulted in most landmasses ____ of the equator.
What might this have contributed to?
north
may have contributed to the climatic instability that set the stage for the glacial cycles of the Pleistocene epoch
T/F
No contribution to biogeography has had more of an impact than the theory of continental drift, and later, plate tectonics theory
false
the theory of evolution probably had a bigger impact
BUT closely followed by plate tectonics/ cont. drift, so it was very important
Who noted that the continents fit together?
Antonio Snider-Pellegrini
Who further extended the concept that the continents fit together?
alfred wegener (starting in 1910)
the theory of plate tectonics provided a mechanism for ______ _____
continental drift
What is a strong piece of evidence for plate tectonics?
mid-ocean ridges and sea floor spreading!
- magnetic fields recorded in the ocean floor
- the ocean floor is a conveyor belt that is being continuously formed at the mid-ocean ridge & destroyed at the trenches, with the continents passively riding along on the conveyor belt
How do magnetic fields get recorded in the ocean floor?
-oceans are formed by the addition of material & spreading at mid-oceanic ridges
- moving away from ridge, the ocean floor increases in age
- pattern of alternating magnetic stripes caused by reversals in earth’s magnetic field
- rocks are formed at the mid-ocean ridge and move away, maintaining their original polarity
- very convincing evidence!
In geological time, what do most major boundaries represent?
periods of mass extinction, followed by adaptive radiation of surviving species
Earliest prokaryotic cells appeared around ____ years ago, and they resemble modern ______ ______
3.5 billion years ago
modern photosynthetic algae
The rise of photosynthesis had what effect on CO2 and O2 levels?
Evidence of this?
reduced atmospheric CO2 and created oxygen!
evidence= deposition of extensive iron oxide sediments on marine continental shelves
Give 2 further pieces of evidence for the rise of photosynthesis (and subsequent oxygen introduction)
- stromatolites in limestone built by photosynthetic cyanobacteria
- extensive banded iron formations
cambrian explosion=
a sudden diversification of life forms and body plans, most of which are extinct today
One of the richest fossil records of the Cambrian explosion can be found where?
Burgess shale!
By Field, BC
The Cambrain Explosion set the stage for biological change over the ____ eon
phanerozoic
List up to 9 drivers of change
- changing solar output
- evolving atmosphere
- tectonic and volcanic activity
- asteroid impacts
- methane clathrate releases
- orbital patterns (Milankovitch)
- changing ocean circulation
- changing sea levels
- humans
What are the 3 main concepts of change?
- predictable rules govern climate change and results in gradual change
- random, abrupt, catastrophic events cause climate change
- the climate alternates between alternate stable states (glacial/ interglacial)
Predictable rules govern climate change and result in gradual change. Explain how CO2 is an example, and give the time frame
A CO2 climate relationship arises with higher atmospheric CO2 under warmer conditions- a correlation found from inter-annual timescales.
Time frame: range from El Nino events to glacial/ interglacial oscillations, to geological timescales
Th evolution of photosynthetic life ___ atmospheric CO2 levels and ____ oxygen
reduced
created
Over geological timescale, have the positions and altitudes of continents remained consistent? What is directly relevant?
No! They’ve changed
- the timing of biological evolution becomes directly relevant
Explain the concept of metastable models for earth history
= the oscillation between 2 stable states
- throughout history, there have been periods of ice-house vs hot-house climate
ie periods of warmth separated by shorter periods of intense cold
Life in the phanerozoic eon shows all __ patterns of change:
3
- gradual
- abrupt
- periodic
T/F
There were mass extinctions in the phanerozoic eon, but not much recovery
false
both catastrophe and recovery
- mass extinctions, followed by rebounds (adaptive radiation)
The evolution of diversity during the phanerozoic eon gradually ___(inc/dec), but was punctuated by major _______
increased
extinctions
Extinctions=
the permanent loss of a species, population, etc
Mass extinctions have occurred many times in geological history. Give 2 examples.
Extinctions are often followed by _____ ______
- Permian-Triassic boundary
- end of cretaceous (K-T boundary)
adaptive radiation
many mass extinctions have been attributed to ______driven cycles of regression and transgression of ____ ____ across continental inland seas
tectonically
marine waters
tectonically-driven regression cycles lead to vast _____ in area of shallow-water environments
decreases
tectonically-driven transgressions may bring masses of ____ waters across expanses of shallow seas
anoxic
T/F
Both tectonically-driven transgression and regression cycles could result in mass extinctions
true
-perhaps in conjunction with additional potential drivers of high-impact environmental change like asteroid impacts
When was the Permian-Triassic Extinction?
250 million years ago
- spanned 60,000 years
t/f
the most disastrous mass extinction was the cretaceous one (associated with the dinosaurs)
false
it was the permian-triassic extinction
What was the scale and scope of the permian-triassic extinction?
-marine
- land tetrapods
- land plants
HUGE
- over 90% of marine invertebrates went extinct
- major loss of other marine species
- more than 75% of land tetrapod (mostly amphibians) extinct
- the majority of land plants extinct
What was the likely cause of the permian-triassic extinction?
Likely more than one causal agent over the time span, including:
- continental drift
- ocean salinity changes
- anoxic, acidic, and sulfidic oceanic conditions
- possible meteorite impact
- extensive volcanism, causing cooling
When was the Cretaceous-Tertiary extinction? What is it best known for?
65 million years ago
- caused the dinosaurs to go extinct
What is the primary cause of the cretaceous believed to be?
a meteorite impact
