Engines of the Planet Lecture

Question 1

What has been the most important factor in causing major, long-term changes in the patterns of organism distribution? (over geological time)

Answer 1

the movement of continents! (Plate tectonics)

Question 2

the movement of land masses across latitude bands resulted in land masses lying in different ____ regions

Answer 2

climatic
= huge impact on organisms on the land masses

Question 3

Tectonic plate movement is responsible for:
- formation of: (list 3)
- destruction of: (list 1)

Answer 3

formation of mountain chains, volcanic islands, and epeiric or epicontinental seas

destruction of epeiric/ epicontinental seas as well

Question 4

How do epeiric/ epicontinental seas form? What are 2 implications of them?

Answer 4

• 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

Question 5

By the end of the Cambrian, ___ fragments had broken away from a supercontinent (Rodinia) that formed over 1 billion years ago

Answer 5

3

Question 6

when did the ancient continents consolidate?

Answer 6

during the carboniferous + permian periods of the paleozoic era

Question 7

The consolidation of the ancient continents resulted in the formation of _____ _______, and eventually, _______…

Answer 7

mountain ranges
the supercontinent Pangaea and the global Panthalassic ocean

Question 8

What are the implications of having one supercontinent and a global ocean?

Answer 8

great connectivity and exchange b/w terrestrial and marine biotas
- eg. pangaea and the global panthalassic ocean

Question 9

separation of the Laurasian and Gondwanan continents during the mesozoic era began as a ____ ____ and expansion of the ___ ___.

What did this lead to?

Answer 9

rift valley

Atlantic sea

This separation eventually led to the opening of the circum-equatorial seaway

Question 10

The onset of the cenozoic era was marked by:

Answer 10

the impact of the chicxulub asteroid and mass extinctions, which were followed by diversification of mammals and other surviving lineages

Question 11

What resulted in the uplift of the Himalayas?

Answer 11

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

Question 12

Continued drifting of the continents during the Neogene and Quaternary periods resulted in most landmasses ____ of the equator.
What might this have contributed to?

Answer 12

north

may have contributed to the climatic instability that set the stage for the glacial cycles of the Pleistocene epoch

Question 13

T/F

No contribution to biogeography has had more of an impact than the theory of continental drift, and later, plate tectonics theory

Answer 13

false
the theory of evolution probably had a bigger impact

BUT closely followed by plate tectonics/ cont. drift, so it was very important

Question 14

Who noted that the continents fit together?

Answer 14

Antonio Snider-Pellegrini

Question 15

Who further extended the concept that the continents fit together?

Answer 15

alfred wegener (starting in 1910)

Question 16

the theory of plate tectonics provided a mechanism for ______ _____

Answer 16

continental drift

Question 17

What is a strong piece of evidence for plate tectonics?

Answer 17

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

Question 18

How do magnetic fields get recorded in the ocean floor?

Answer 18

-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!

Question 19

In geological time, what do most major boundaries represent?

Answer 19

periods of mass extinction, followed by adaptive radiation of surviving species

Question 20

Earliest prokaryotic cells appeared around ____ years ago, and they resemble modern ______ ______

Answer 20

3.5 billion years ago

modern photosynthetic algae

Question 21

The rise of photosynthesis had what effect on CO2 and O2 levels?

Evidence of this?

Answer 21

reduced atmospheric CO2 and created oxygen!

evidence= deposition of extensive iron oxide sediments on marine continental shelves

Question 22

Give 2 further pieces of evidence for the rise of photosynthesis (and subsequent oxygen introduction)

Answer 22

1. stromatolites in limestone built by photosynthetic cyanobacteria
2. extensive banded iron formations

Question 23

cambrian explosion=

Answer 23

a sudden diversification of life forms and body plans, most of which are extinct today

Question 24

One of the richest fossil records of the Cambrian explosion can be found where?

Answer 24

Burgess shale!

By Field, BC

Question 25

The Cambrain Explosion set the stage for biological change over the ____ eon

Answer 25

phanerozoic

Question 26

List up to 9 drivers of change

Answer 26

• changing solar output
• evolving atmosphere
• tectonic and volcanic activity
• asteroid impacts
• methane clathrate releases
• orbital patterns (Milankovitch)
• changing ocean circulation
• changing sea levels
• humans

Question 27

What are the 3 main concepts of change?

Answer 27

1. predictable rules govern climate change and results in gradual change
2. random, abrupt, catastrophic events cause climate change
3. the climate alternates between alternate stable states (glacial/ interglacial)

Question 28

Predictable rules govern climate change and result in gradual change. Explain how CO2 is an example, and give the time frame

Answer 28

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

Question 29

Th evolution of photosynthetic life ___ atmospheric CO2 levels and ____ oxygen

Answer 29

reduced
created

Question 30

Over geological timescale, have the positions and altitudes of continents remained consistent? What is directly relevant?

Answer 30

No! They’ve changed
- the timing of biological evolution becomes directly relevant

Question 31

Explain the concept of metastable models for earth history

Answer 31

= 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

Question 32

Life in the phanerozoic eon shows all __ patterns of change:

Answer 32

3
- gradual
- abrupt
- periodic

Question 33

T/F

There were mass extinctions in the phanerozoic eon, but not much recovery

Answer 33

false

both catastrophe and recovery
- mass extinctions, followed by rebounds (adaptive radiation)

Question 34

The evolution of diversity during the phanerozoic eon gradually ___(inc/dec), but was punctuated by major _______

Answer 34

increased
extinctions

Question 35

Extinctions=

Answer 35

the permanent loss of a species, population, etc

Question 36

Mass extinctions have occurred many times in geological history. Give 2 examples.

Extinctions are often followed by _____ ______

Answer 36

• Permian-Triassic boundary
• end of cretaceous (K-T boundary)

adaptive radiation

Question 37

many mass extinctions have been attributed to ______driven cycles of regression and transgression of ____ ____ across continental inland seas

Answer 37

tectonically

marine waters

Question 38

tectonically-driven regression cycles lead to vast _____ in area of shallow-water environments

Answer 38

decreases

Question 39

tectonically-driven transgressions may bring masses of ____ waters across expanses of shallow seas

Answer 39

anoxic

Question 40

T/F

Both tectonically-driven transgression and regression cycles could result in mass extinctions

Answer 40

true

-perhaps in conjunction with additional potential drivers of high-impact environmental change like asteroid impacts

Question 41

When was the Permian-Triassic Extinction?

Answer 41

250 million years ago

• spanned 60,000 years

Question 42

t/f

the most disastrous mass extinction was the cretaceous one (associated with the dinosaurs)

Answer 42

false
it was the permian-triassic extinction

Question 43

What was the scale and scope of the permian-triassic extinction?

-marine
- land tetrapods
- land plants

Answer 43

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

Question 44

What was the likely cause of the permian-triassic extinction?

Answer 44

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

Question 45

When was the Cretaceous-Tertiary extinction? What is it best known for?

Answer 45

65 million years ago
- caused the dinosaurs to go extinct

Question 46

What is the primary cause of the cretaceous believed to be?

Answer 46

a meteorite impact