Chapter 3-5 geology
Terms in this set (74)
What was the earth's climate like 50 million yeard ago, what caused the clomate to change?
Warmer and wetter with abundant rainforests; movements of continents around face of the planet
What is air doing over the tropics; over the poles?
Tropics-air rises and moisture in the air cools and condenses; air falls pushing outwards
What 2 things are driven by the temperature gradient between the poles and the equator?
Wind Movements and currents in the ocean
How long have the continents been in their present configuration?
100 million years
What 2 tectonic events caused Antarctica to start building ice around 35 million years ago?
-Isolation of Antarctica
-cold air current developed, drake passage
How does the circulation of the ocean water completely around Antarctica affect its climate?
It sucks out heat from the continent and keeps it cold
What caused a second phase of cooling to begin around 10 million years ago according to Maureen Raymo?
The uplift of the Tibetan-Himalayan and Sierran-Coloradan regions contributed to the cooling of the global climate through a massive increase in erosion
The weathering of what type of rock actually removes carbon dioxide from the atmosphere?
How long is the carbon dioxide that is pulled from the atmosphere by the weathering of this rock type locked up on the ocean floor?
They're lost from the global carbon cycle for the duration of the life cycle of the oceanic crust on which they've been deposited
Although huge Ice sheets began to form on Antarctica and Greenland by 5 million years ago why didn't the ice age begin until 2.5 million?
Terminal Messinian flood
What caused the Mediterranean Sea to dry up 6 million years ago?
The straits of Gebraltar Closing
How much salt was removed from the worlds oceans during this Messinian Salinity Crisis?
How did the Terminal Messinian Flood stop the Ice Age in its tracks at 5 million years ago?
Strait of Gibraltar re-opened and it started the ocean conveyer belt back up
What 2 agents control deep circulation of the ocean?
Salt and heat
How does evaporation in the Carribean contribute to the formation of the North Atlantic Deep Water in the Nordic Sea north of Iceland?
Provides a source of salt
How long does it take for a parcel of water to flow around the whole of the great global ocean conveyer belt?
About 1,000 years
Although London and Labrador are at the same latitude, why are their winters so different?
This is due to the heat released by the Gulf Stream
How did the closure of the Pacific-Caribbean gateway 2 million years ago both help and hinder the start of the Ice age?
Hindered- the salt in the water enhanced deep water formation and heat transport to high latitudes
Help- helped the ocean conveyer belt by dumping salt into it
What was the tilt of the earth like (Max or min.) at 5 and 2.5 million years ago?
What two things are affected by Walker circulation?
The periodic switching of the direction and intensity of ocean currents and winds in the Pacific
Why were we only able to identify 4 glacial/interglacial cycles on land; how was this problem resolved?
Due to erosion by later glacial advances; by sediment cores in the ocean
Based on this new source of info, how many glacial/interglacial have we identified?
50 glacial periods
What was the length of these cycles between 2.5 and 1 million years ago; after 1 million years?
Every 41,000 years; every 100,000 years
Instead of names how do we identify the different glacial/interglacial cycles today?
Numbers: odd = interglacial, even = glacial
How does the severity of glacial/interglacial cycles differ between those before 1 million and those after?
Before: transitions between glacial and interglacial periods regular and balanced
After: greater amounts of ice accumulated, amplitude of warm interglacials and cold glacial increased
What are the names of the 4 ice sheets that covered North America?
Laurentide, Cordilleran, Greenland, inuitan
What are the names of the 3 ice sheets that covered Europe?
Scandinavian, British ice sheets, and minor one covering the Alps
If all the ice on Antarctica and Greenland today melted how high would it raise sea level?
How do present carbon dioxide levels compare with those of past interglacials?
Interglacial levels dropped 280 PPM then rose 180 PPM. Now at 440 PPM AND climbing
What is ice-albedo feedback?
The more ice you have, the cooler it gets
How can the height of an ice sheet promote continued glaciation?
Reducing the formation of deep water reduces the amount of warm water leading to increased cooling
How does moisture limitation counterbalance these previous 2 feedbacks mechanisms?
There's a decrease in supply of moisture required to build ice sheets
What are Heinrich Events?
Massive collapses of the North American Laurentide ice sheet that float out into the ocean
How can we follow these armadas of ice bergs as they shift across the Atlantic Ocean?
They're easy to spot in marine sediment cores as they leave a trail of rock fragments over the ocean floor
How can these armadas of icebergs disrupt the ocean conveyer belt?
With the high amounts of salt
How often did Heinrich Events occur during the last glacial cycle, how long did they last?
Every 7,000 years; 3 years
What are the Dansgaard-Oeschger Cycles; how often do they occur?
Smaller events occurring at about every 1,500 years
What is the relationship between Heinrich Events and Dandgaard-Oeschger Cycles?
Dansgaard are steps in the cycle and Heinrich events are super Dandgaard-Oeschger Cycles
What are Dandgaard-Oeschger Cycles called during interglacial periods?
What two things allowed these hominoids to expand out of Africa at 1.8 mya?
Larger brains and tools
What is the centerpiece of the human story; why?
The mind; only humans have developed the mind processing info and generating it
When do fossils that clearly represent early human-like beings first appear; how old are the earliest fossils that may be human like?
4.4 mya; 15 million mya
What is the key anatomical feature used to identify early human-like beings; why was this feature so key to human development?
Bipedalism; freed their hands to manipulate the world around them
What benefit did this anatomical feature give humans; what environmental change may have stimulated the development of this anatomical feature?
They use less energy; walking evolved in response to shrinking forests and expansion of open woodland
When did the first recognizable tools appear and what forms of Homo may have made them?
2.5 million years ago; Homo habilis
Where do we find the 1st evidence that humans had moved out of Africa and into Eurasia by 1.8 mya; what were 3 types of evidence recovered?
Site of Dmanisi (Republic of Georgia, Russia)
1) stone tools
2) human skeletal remains
3) mammal bones with cut marks
What is the anatomical significance of Narokotome Boy; what new type of tool was introduced; what is the relationship between Homo ergaster and homo erectus?
Essentially a modern human from the neck down including his hands; handaxe; homo erectus are viewed as an Asian variant of the same people found in Africa
What new hominid; new tool type; and new technology appeared in Africa 750,000 years ago; at what site in Israel and England was evidence found for these new innovations?
Homo heidelbergensis; Musterian tool tradition; Israel: Gesher Benot Ya'aqov (Fire harth & hand axes), England: Boxgrove (hand axes)
How does the diet of humans differ from that of animals; what 2 approaches do scientists use to study diet?
Humans have an omnivorous diet;
1) study of food remains found in association w/ human fossils and artifacts
2) chemical analysis of humans bone and teeth
List 3 ways that humans and their bodies adapt to cold weather
1) they have shorter limbs and a heavier body mass
2) an increase in meat intake
3) control of fire
How did homo heidelbergensis occupations at Boxgrove in England differ from contemporaneous Homo erectus occupations at Longgushan in China?
Longgushan in China: retreated southwards
Boxgrove: stayed put and didn't travel south
At what site do we find the 1st evidence that Homo ergaster may have controlled fire; when?
Swartkrans Cave in South Africa; 1.5 million years ago
At what site do we find the 1st evidence that Homo heidelbergensis may have controlled fire; when?
Gesher Benot Ya'aqov in Israel; 800,000 years ago
Based on genetic studies what hominid was the common ancestor of both Homo neanderthalensis and Homo sapiens?
When did the Neanderthals die out?
About 30,000 years ago
How were Neanderthals adapted to the cold?
They have heavier bodies which helped conserve body; also had unusually wide openings in cheek bone to allow enough blood flow to the face
What did the Neanderthals do during the glacial stages?
Stayed put and lived in caves
What are the two lines of evidence that tell us that Neanderthals were making "composite tools"?
1) traces of wear caused by friction from wooden handle or shaft
2) surfaces of some stone points and flakes exhibit residues of adhesive used to attach them
What technology did the Neanderthals lack that could've helped them to better adapt to the cold?
The Sewing Needle
How do we know that Neanderthals were hunting mammoth and woolly rhino?
Analysis of their bone chemistry
What was one technique that Neanderthals used to hunt these large animals?
They drove them off cliffs
What do the lack of Neanderthal symbolism and art possibly tell us about their language?
It lacks the creativity that we see in syntactical language
What unique practice did Neanderthals share with modern humans?
Burying their dead
When do anatomically modern humans first appear in Africa; where?
200,000 years ago in Ethiopia
When do modern humans begin to expand out of Africa and into Eurasia?
Started 100,000 years ago
When did modern humans reach Australia?
Around 50,000 years ago
Who were the Aurignacian people, what was the climate like when they arrived, what are they famous for?
First modern humans in Western Europe; very cold; paintings and sculptures
How were the Aurignacian paintings dated; to what date?
Radiocarbon dating; more than 30,000 years ago
What were the 1st fired ceramic objects that were made around 30,000 years ago?
When did the earliest example of a spear thrower atlatl appear?
Almost 20,000 years ago
What was unique about the houses at Mezhirich in Ukraine?
They were assembled from mammoth bones and tusks
When and where do the earliest pottery vessels appear?
Found in Japan and on the Asian mainland as early as 16,000 years ago
What is the connection between Dyuktai Cave in Siberia and the Tanana Valley in Alaska?
Found tools which enabled them to travel and carried them to Alaska
What were the 3 routes by which humans may have reached the U.S.?
1) island hopping
2) ice-free corridor opened between Rocky Mountains & central Canada
3) could pull boat up on ice (ice shelf could be traveled on further South)
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