3.1 C: Geology = the Changing Earth 3.1 The Great Cooling Flashcards
What is the Cypress Hills Interprovincial Park described as?
An island of forest within a sea of grassland
The park is located on the southern border of Alberta and Saskatchewan.
Why does Cypress Hills receive more precipitation than surrounding areas?
Due to its higher elevation
This extra moisture supports a rich forest ecosystem.
What geological feature provides clues about Alberta’s past?
A 600-m thick section of sedimentary rock
This section was not removed by the advancing ice sheet during the most recent Ice Age.
What was the area of Cypress Hills suspected to be during the last Ice Age?
An island of land in a sea of ice called a Nunatak
‘Nunatak’ is Inuktitut for ‘land apart’.
What era is known as the last 65 million years of Earth’s history?
Cenozoic Era
The Cenozoic Era is divided into two periods: the Tertiary and Quaternary.
What are the two periods of the Cenozoic Era?
Tertiary Period and Quaternary Period
Tertiary: 65 million years ago to 1.7 million years ago; Quaternary: 1.7 million years ago to the present.
What percentage of the Cenozoic Era does the Tertiary Period represent?
Over 97%
The Tertiary Period is much longer than the Quaternary Period.
What geological event occurred at the beginning of the Cenozoic Era?
Collision between the North American Plate and the Pacific Plate
This resulted in a rapid period of mountain building.
What mountain range was formed due to the geological events of the Cenozoic Era?
Rocky Mountain Range
This mountain building process ended about 50 million years ago.
How were the Rocky Mountains characterized at the time of their formation?
Round-looking mountains covered with V-shaped valleys
The valleys were cut out by erosion.
What geological process caused Alberta and North America to migrate northward?
The relentless march of the tectonic plates
How did the migration of North America affect its climate?
It got cooler
What significant geological feature was formed as a result of glacial activity in North America?
The familiar jagged features of the Rocky Mountains
Approximately how many years ago did the icy process that carved the Rocky Mountains begin?
1.7 million years ago
What happened to the Bearspaw Sea at the beginning of the Cenozoic Era?
It retreated to the southwest
What geological formation was left in southern Alberta after the retreat of the Bearspaw Sea?
The Bearspaw sedimentary rock formation
What type of fossils is the Bearspaw sedimentary rock formation rich in?
Dinosaur fossils and other fossils
During the Cenozoic Era, what was a new source of sedimentary rock in Alberta?
Runoff from the rising Rocky Mountain Range
What geographical feature did large rivers create as they flowed down during the Cenozoic Era?
V-shaped valleys
Fill in the blank: During the late Cretaceous Period, much of southern Alberta was submerged under the _______.
[Bearspaw Sea]
True or False: The retreat of the Bearspaw Sea had no impact on the sedimentary rock formations in Alberta.
False
What significant climatic change occurred during the first 15 million years of the Tertiary Period?
A significant drop in average global temperatures
This cooling affected both animal and plant life.
What type of forests replaced tropical forests during the Tertiary Period?
Temperate evergreen forests scattered with rivers, lakes, and swamps
This transition marked a significant change in plant life.
How did the temperatures during the Tertiary Period compare to the Cretaceous Period?
Cooler than the Cretaceous Period but still warmer than today
This indicates a gradual cooling trend over time.
Approximately how much of the Tertiary Period is thought to have featured climate resembling present-day southern Louisiana?
About two-thirds of the way through the Tertiary Period
This suggests a significant climatic shift in Alberta.
What significant climatic change occurred during the first 15 million years of the Tertiary Period?
A significant drop in average global temperatures
This cooling affected both animal and plant life.
What type of forests replaced tropical forests during the Tertiary Period?
Temperate evergreen forests scattered with rivers, lakes, and swamps
This transition marked a significant change in plant life.
How did the temperatures during the Tertiary Period compare to the Cretaceous Period?
Cooler than the Cretaceous Period but still warmer than today
This indicates a gradual cooling trend over time.
Approximately how much of the Tertiary Period is thought to have featured climate resembling present-day southern Louisiana?
About two-thirds of the way through the Tertiary Period
This suggests a significant climatic shift in Alberta.
What period did evergreen forests begin to dominate in Alberta?
Tertiary Period
This marks a significant shift in the types of forests present during this geological time.
What type of mammals survived the Cretaceous Extinction?
Mainly small rodents
These mammals took advantage of the ecological niches left by the extinct dinosaurs.
What significant change occurred in mammal evolution by 40 million years ago?
Many new forms of mammals appeared in the fossil record
These included ancestors of modern hooved herbivores, flesh-eating carnivores, and large-brained primates.
What were the ancestors of modern hooved herbivores, flesh-eating carnivores, and large-brained primates known for?
They appeared in the fossil record around 40 million years ago
This diversification marked a key evolutionary step for mammals.
Fill in the blank: By 65 million to 40 million years ago, mammals _______ and flourish.
diversify
This period was crucial for the development of various mammalian species.
What does the fossil skull noted for its relatively large brain represent?
One of the earliest ancestors of modern primates
This fossil is around 195 million years old, indicating an early development of primate traits.
What adaptation of grasses allowed them to withstand the cooler and drier climate of the late Tertiary Period?
Dense root structure
The dense root structure of grasses is crucial for survival in challenging climates.
How many species of grasses are found worldwide?
About 9000 species
Grasses are versatile and can thrive in diverse environments.
When did the first grass species appear in the fossil record?
Early in the Tertiary Period
Grasses began to dominate later in the Tertiary Period.
What climatic changes occurred in Alberta during the late Tertiary Period?
Significantly cooler and drier
These changes influenced the type of vegetation that thrived.
What type of mammals gained a survival advantage due to the dominance of grasses?
Ruminants
Ruminants can digest cellulose, which is beneficial for consuming grasses.
What is the main component of plant cell walls that ruminants can digest?
Cellulose
Ruminants have specialized digestive systems for processing cellulose.
What is a significant advantage of grasses over other plants in response to grazing?
Grasses grow from the base
This growth pattern allows grasses to recover more effectively from grazing.
What transformation did the wetlands of the early Tertiary Period undergo?
Into drier woodlands and then into grasslands
This transition reflects significant ecological changes in the region.
True or False: The resistance of grasses to grazing is an adaptation that contributed to the transformation of Alberta’s landscape.
True
The ability of grasses to withstand grazing pressures allowed them to dominate.
What type of environment became prevalent in Alberta due to the dominance of grasses?
Grassland
This environment supported large herds of grazers and their predators.
What overall trend occurred during the Tertiary Period?
Cooling trend
This was one of many climate changes in Earth’s past.
What type of evidence do scientists use to study past climate changes?
Sedimentary rocks
These rocks contain fossils and other indicators of historical climates.
What do tropical plant and animal fossils found in polar regions indicate about past climates?
These regions were much warmer in the past
The presence of such fossils suggests a significantly different climate.
What does the absence of tree pollen in current tropical landscapes suggest?
The past climate was too cold for trees to survive
This indicates significant historical climate variation.
What do sedimentary rock layers provide for scientists studying the Tertiary cooling trend?
Many clues about past climates
The layers contain various indicators of historical environmental conditions.
What overall trend occurred during the Tertiary Period?
Cooling trend
This was one of many climate changes in Earth’s past.
What type of evidence do scientists use to study past climate changes?
Sedimentary rocks
These rocks contain fossils and other indicators of historical climates.
What do tropical plant and animal fossils found in polar regions indicate about past climates?
These regions were much warmer in the past
The presence of such fossils suggests a significantly different climate.
What does the absence of tree pollen in current tropical landscapes suggest?
The past climate was too cold for trees to survive
This indicates significant historical climate variation.
What do sedimentary rock layers provide for scientists studying the Tertiary cooling trend?
Many clues about past climates
The layers contain various indicators of historical environmental conditions.
