Unit 6 Poss. Test Questions Flashcards
What percentage of time is represented by the Paleozoic Era since the Precambrian?
The Precambrian (early life) Era of the Phanerozoic (visible life) Eon represents almost 50% of the time since the Precambrian (a total of 291 MY).
What type of fossil was used to redefine the Precambrian-Cambrian boundary in 1991?
First appearance of trace fossils.
Sort the seven (7) periods of the Paleozoic Era in order from oldest to youngest.
- Cambrian (oldest)
- Ordovician
- Silurian
- Devonian
- Mississippi
- Pennsylvania
- Permian
How does the US subdivide the Carboniferous Period?
Mississippian and Pennsylvanian.
What was Laurentia?
Ancestral North America.
In the Early Paleozoic, where was Texas located (in reference to the equator)?
South of the equator.
What is the eustatic sea level?
World-wide sea levels.
Describe an epicontinental sea.
Widespread, shallow seas that transgress or regress over a craton.
What is a transgressive sea?
A rise in sea level, generally over a craton.
Describe (draw) a rock sequence associated with a transgressive sea.
Bottom to top: Sandstone, Shale, then Limestone.
What is a regressive sea?
A fall in sea level, generally off a craton.
Describe (draw) a rock sequence associated with a regressive sea.
Bottom to top: Limestone, Shale, then Sandstone.
In general, what can be said about average sea levels during the Cambrian as compared to today?
Epicontinental seas cover a large portion of the North American craton.
What was the transcontinental arch?
A series of large, late Cambrian island arcs that extended to southern New Mexico and West Texas
Where do we find Cambrian age rock in Texas?
- Bliss Sandstone (El Paso area)
- Enchanted Rock area (Central Texas)
- Hickory Sandstone (Mason, Texas
What is the Cambrian explosion?
The sudden appearance of other diversified shelly metazoans.
Why would animals with protective shells be more likely to survive?
Having protective shells means they won’t get eaten.
What is meant by “unknown phyla” of the Cambrian?
Many animals of the Burgess shale are “unknown phyla” - have no living organisms with their basic body plan.
Which geologic period had the most diverse phyla?
The Cambrian Period.
What is the significance of the Cambrian Chinese fossil site and it’s fossils?
- The fossils here are really complex considering that complex life is just beginning on Earth.
- This implies that the Cambrian explosion may have occurred in as little as 10 MY.
Why are the Burgess shale and its fossils so important to understanding the Cambrian Period?
The Burgess shale contains some of the best period examples of soft bodied flora and fauna known.
What represents the first known vertebrate?
Fish.
What period is known as the Age of the Trilobites?
The Cambrian Period.
What marks the end of the Cambrian?
Colder temperatures and mass extinction of most of the trilobites.
What type of tectonic zone is associated with orogenies?
Convergent zones. {Colliding plates}
Which mountains were formed with the Taconic Orogeny?
The Appalachian Mountains.
Why do mountains persist for hundreds of millions of years despite erosion?
Isostasy: the concept of the Earth’s crust floating on a dense underlying layer.
-Can be illustrated by a cork in floating water.
Isostatic rebound: the phenomena in which unloading (erosion) of the crust (mountains) causes the crust to rise until it attains equilibrium.
What do we call the deeper parts of mountains?
Mountain roots.
Why is the Ordovician Ellenberger Formation important to Texas?
Oil and gas.
When did plants become widespread in the seas?
The Ordovician Period.
Which plants may have invaded land during the Ordovician?
Primitive algae and lichens.
Why is the Silurian Period Fusselman Dolostone important to Texas?
The Fusselman Dolomite is a major oil and gas producer.
What major evolutionary step did fish undergo during the Silurian?
The first fish with jaws would develop during the Silurian Period.
Which was the first life form that moved onto land?
Algae and vascular plants. [Earliest known: Psilopsids]
What was the first animal life form that moved onto land?
The earliest animals on land would be insects.
During what period did this land invasion take place?
Silurian.
At the end of the Devonian, Laurentia is now called _______.
Laurasia (?)
What state contains a large portion of the mini-continent Antler Highlands?
Nevada
What mineral is associated with the Antler Highlands?
Gold mining.
What period is called the Age of Fish?
The Devonian Period.
What is a tetrapod?
Vertebrate animals having 4 feet or leg-like appendages (excludes fish)
What advantage might a lobe-fin give to a fish?
Able to move to more places in order to feed.
Besides insects, which was the second group of animals to invade the land?
Fish.
When did Earth’s second mass extinction occur?
At the end of the Devonian.
Name an important Mississippian Period formation found in Texas and why is it important?
The Barnett Formation has oil and gas wells, contributes +$100 to the Texas economy.
What type of eggs had to evolve for animals to advance to other environments?
Amniotic eggs.
Which Period is known as the Age of the Insects?
The Pennsylvanian Period.
How long has cockroaches been around?
The Pennsylvanian Period.
Which Texas uplift is associated with the Ouachita Orogeny?
Llano Uplift.
Which widespread energy “mineral” was formed in the Pennsylvanian Period?
Major swamps are located along the equator, which will become vast coal deposits.
Where are Pennsylvanian Period age rocks found in Texas?
Pennsylvanian limestone.
Name the three orogenies associated with the Appalachian Mountains?
Taconic, Alleghanian, _________
How long will Earth’s fourth ice age last in the Permian?
For half of the Permian Period.
Which thick evaporate deposit was formed in the Texas Permian basin?
Castile Gypsum.
Which Texas mountain cliff is an ancient Permian reef?
El Capitan in the Guadalupe Mountains.
What valuable resource is found in the Texas Permian basin?
The Permian Basin is famous for its huge oil and gas deposits.
What do Seymouria, Eryops, and Diplocaulus have in common?
Large primitive amphibians living along the shorelines of Texas.
Which carnivorous mammal-like reptiles occurred in the Permian Period and also in Texas?
Dimetrodons.
Where have Dimetrodons been found in Texas?
Dimetrodon skeletons have been found in Archer County, North Texas.
What can be considered mammal-like?
Primitive differentiation of teeth.
What happened at the end of the Permian (life forms)?
The end of the Permian Period results in the largest mass extinction event ever recorded on Earth.
During which three Paleozoic Periods did Earth suffer major extinctions?
Ordovician, Devonian, Permian
Which of the three Paleozoic Periods were the worst?
Permian.
What is the probable cause of this [worst Paleozoic Period] extinction?
We do not know for certain. [heat/deserts everywhere]
What defines a mass extinction?
The planet-wide disappearance of a species or higher taxonomic group, twice the background rate.
What is the effect of extinction of a major dominant species?
The extinction of a large number of dominant species is instrumental in the expansion of “minor” species to fill the niche left open.
