GEO 1404- Exam #3 Flashcards
WHAT IS ARTIFICIAL SELECTION?
selectively breeding plants & animals w/ desirable traits
Examples: vegetables, domestic dogs ( came from domesticated grey wolves)
WHAT IS THE BASIC IDEA BEHIND NATURAL SELECTION?
a natural process was selecting a few individuals for survival
WHAT ARE THE 4 MAIN CONCEPTS OF NATURAL SELECTION?
- inheritable
- there are favorable traits
- not all young survive
- favorable traits more likely to survive and pass on those traits
HOW DID MENDEL’S EXPERIMENTS SUPPORT THE CONCEPT OF NATURAL SELECTION?
- Genetic experiments using garden pea plants
- Traits are controlled by genes
- Was able to show how the traits were passed on
o Show that genetic traits can be passed on to offspring & offspring will have a mixture of traits
o Dominant and recessive gene traits/alleles: variant of a single gene
o The variations don’t blend in or get lost. May not show up for generations, but it’s still a part of the genetic material
DESCRIBE MICROEVOLUTION
Change in the genetic makeup of a species
→changes occur w/in a species (usually between generations)
DESCBIVE MACROEVOLUTION
the origin of new species
*Macroevolution is simply the cumulative effect of microevolution over generations
WHAT IS A SPECIES?
Population of similar individuals that can successfully procreate
WHAT IS SPECIATION?
evolution of a new species
WHAT 3 THINGS ARE CRITICAL FOR SPECIATION TO OCCUR?
- Barrier/Transport
- Natural Selection
- Random Genetic Drift
DESCRIBE ALLOPATRIC SPECIATION.
HOW CAN ISOLATION OF A SMALL POPULATION OCCUR?
A new species population becomes isolated from its parent population
* Creation Of A Land Barrier
* Rise In Sea Level
* Transport To A Remote Area
WHAT IS EXTINCTION?
complete disappearance of a species
WHAT IS A MASS EXTINCTION?
Extinction of many species over short time
WHAT ARE SOME POSSIBLE CAUSES OF PAST MASS EXTINCTIONS?
-Major environmental disturbances
-volcanic activity
-rise/fall in sea level
-meteorite impact
-disease
-loss of food source
WHAT ARE THE 4 BASIC TIME UNITS OF THE GEOLOGIC TIME SCALE? WHICH REPRESENTS THE LARGEST AMOUNT OF TIME? THE SMALLEST AMOUNT OF TIME?
o Eon, Era, Period, Epoch
WHAT IS THE ESTIMATED AGE OF THE EARTH?
o 4.6 Billion years old
WHAT MATERIALS HAVE BEEN DATED TO SUPPORT THIS AGE?
o Metamorphic Rock
o Minerals: zircon (mineral) crystals
o Moon Rocks
o Meteorites
WHAT IS A PROTOCONTINENT?
Landmass that could become a larger continent or smaller ones
OXYGEN FORMED IN THE ENVIRONMENT IN WHAT 2 WAYS?
PHOTOCHEMICAL DISSOCIATION & PHOTOSYNTHESIS
WHAT WAS THE CRUST LIKE FOR THE EARLY EARTH (DURING THE ARCHEAN)?
2 types of crust once magma ocean cooled:
Oceanic- mafic- basalt
continental- felsic- granite
WHAT ARE MAFIC ROCKS?
Name break down
- Example
- Color
-Type of Volcano
o MA- Magnesium, FIC- Iron
o EX: Basalt
o dark-colored minerals
o Mafic Volcano- Hawaii- don’t have to run away, low viscosity
WHAT ARE FELSIC ROCKS?
Name break down
- Example
- Color
-Type of Volcano
o FEL- Feldspar , SIC- Silica
o EX: granite
o light-colored minerals
o Felsic Volcano- Mt St Helens- explosive eruption, high viscosity (very sticky)
HOW DID THE MAGMA OCEAN TURN INTO THE CRUST?
Magma + Silicate Minerals (Silica + oxygen) = Igneous Rocks = Crust/ Mantle
IF THE INITIAL CRUST WAS MAFIC/ULTRAMAFIC IN COMPOSITION, HOW DID THE COMPOSITION EVENTUALLY CHANGE?
*Plate tectonics
*Subduction
DESCRIBE HOW THE EARLY CONTINENTS FORMED.
Movement of plates, pieces collide, small continents formed called protocontinents
WHAT IS A CRATON?
-Sheild- exposed
- Platform- beneath
- Oldest rocks on earth
- Core continental of plates
DESCRIBE THE 2 BASIC COMPONENTS OF A CRATON.
1) SHIELD= exposed
2) PLATFORM= beneath
WHAT IS OUTGASSING?
HOW IS THE PROCESS OF OUTGASSING RELATED TO THE FORMATION OF EARTH’S EARLY ATMOSPHERE?
Gases during volcanic activity
Carbon dioxide & water vapor into atmosphere
No Oxygen
WHAT WERE THE COMMON GASES IN THE ARCHEAN?
WHAT IMPORTANT GAS WAS MISSING?
-Carbon Dioxide
-Nitrogen
-Hydrogen
-Water Vapor
What’s missing??? OXYGEN
DESCRIBE THE LIFE OF THE ARCHEAN EON.
organisms- single-celled prokaryotic
extreme environments
Bacteria
WHAT IS THE OLDEST FOSSIL EVIDENCE?
Type?
Found Where?
Preserved in?
How old?
- single-celled prokaryotes
-found in Australia
-preserved in chert
-3.4 billion yrs old
WHAT ARE STROMATOLITES?
‘layered rock’
sedimentary structure
microbial reefs
created by cyanobacteria
HOW DID STROMATOLITES CONTRIBUTE TO THE GASES IN THE ATMOSPHERE?
- Releasing oxygen from photosynthesis
- Enabledmore complex life forms
WHAT WAS LAURENTIA?
First large landmass
Plate collision
Proterozoic Accretion
o Greenland
o North America
o Scotland
o Scandinavia
HOW DO GREENSTONE-GRANITE BELTS FORM?
Ocean Basin + layers of volcanic & sed rocks
Meta: Heat & pressure= new minerals (green)
Squished between plates
WHAT WAS THE GRENVILLE OROGENIC BELT?
What can be found here?
Evidence of what?
Place, mountain building, more than 1 mountain
- the Adirondacks and Blue Ridge mountains.
- Oldest Rocks on earth
- Evidence of:
1. supercontinents merging
2. breaking apart
3. opening a new ocean basin.
DEFINE OROGENIC BELT:
Oregeny with more than 1 mountian
DEFINE OROGENY:
-mountain building process
-convergent plate margin
-plate motion compresses the margin
APPROXIMATELY 1.0 BILLION YEARS AGO, THE FORMATION OF LAURENTIA WAS COMPLETE. HOW MUCH OF PRESENT-DAY NORTH AMERICA EXISTED?
75%
DESCRIBE THE SUPERCONTINENT CYCLE.
** AVENGERS
Supercontinents have:
- assembled
- fragmented
- reassembled
- repeat
at different times throughout Earth’s history
NAME THE 3 SUPERCONTINENTS OF THE PROTEROZOIC EON.
- Nuna
- Rodinia
- Pannotia
WHAT IS THE SNOWBALL EARTH HYPOTHESIS?
The entire surface of earth experienced repeated cycles (at least 2) of freezing & thawing during late Proterozoic
EXPLAIN THE IDEA THAT EARTH EXPERIENCED MULTIPLE EPISODES OF GLACIATION DURING THE PROTEROZOIC.
WHAT EVIDENCE HAS BEEN FOUND TO SUPPORT THIS IDEA? (5)
Multiple episodes of glaciation occurred during Proterozoic
-Tillites & Striations
-Dropstones- Rocks picked up by glaciers and show up all over the planet
-Rocks preserved signs of Earth’s ancient magnetic field.
-The presence of ice found in rocks that were near the Equator
WHAT ARE BANDED IRON FORMATIONS
- ________ structure
- layers of __ & ___
- formed in what kind of environment?
- caused by?
(BIF):
- Sedimentary Structure
- layers of iron-rich minerals & chert
- formed in the marine environment
- Caused by: the emergence of life (cyanobacteria)
HOW ARE BIFS ASSOCIATED W/ EARTH’S EARLY ATMOSPHERE?
Sed rock
Rainbow
think formed in oceans because of oxygen production by cyanobacteria photosynthesis
WHAT ARE CONTINENTAL RED BEDS?
FORMED WHERE?
EVIDENCE OF WHAT?
- beds of sedimentary rock colored by iron oxides
- formed in nonmarine environments
-Evidence of: oxygen increasing
Oxidation= rust= so it must have been in the atmosphere
WHAT IS A PROKARYOTE?
simple cell structure,
no nucleus,
small
WHAT IS A EUKARYOTE?
complex structure
w/organelles
nucleus
larger
DESCRIBE THE EDIACARAN FAUNA.
Name means?
What are they?
Where are they found?
Ediacaran is a period
- fauna is “the animals of a particular geologic period”
-Oldest Fossils Of Macroscopic Animal Life
-1ST FOUND In: Southern Australia
-On Every Continent, Except Antarctica
WHERE WERE THE 1ST FOSSILS FOUND?
Southern Australia
The Paleozoic era is a part of which eon?
Phanerozoic (Today’s)
Paleogeography definition:
study of Earth’s ancient geography
What is a craton?
The 2 parts?
- core of continental plates
-Foundation for our continents today
- Shield- exposed
- Platform- Mostly underground with sedimentary layers on top of it
What is an epeiric sea?
These happen when?
What is the cycle?
inland sea in interior of continent
-Sea Level Up= Sediment Deposit
-Sea Level Down= Land Exposed= Weathering/Erosion
-Repeat
WHAT IS A MARINE TRANSGRESSION?
rise in sea level; landward migration of the shoreline
WHAT IS A MARINE REGRESSION?
drop in sea level; migration of shoreline seaward →more land is now exposed
What is a cratonic sequence?
What is the order of the sequence?
a major transgressive & regressive cycle recorded in sed rocks
-Sea Level Up= Sediment Deposit
-Sea Level Down= Land Exposed= Weathering/Erosion
-Repeat
What was the first major transgressive sequence onto the North American craton?
The Sauk sequence
What happened during the Sauk sequence?
Late Proterozoic to the Early Ordovician
*Records 1st major marine transgression
North America was at the equator (red line)
-Sea Level Up= Sediment Deposit
-Sea Level Down= Land Exposed= Weathering/Erosion
-Repeat
What role did barrier reefs play in the precipitation of evaporites during the Tippecanoe Sequence?
Resulting in… (3)
What is mined for in these areas today?
Location along the equator provided warm water for reef-building organisms to thrive.
-widespread coral reefs & barrier reefs
-barrier reefs restricted the circulation of seawater
-precipitation of evaporites once sea regressed in the Late Silurian
-Rock salt and rock
Describe the events that occurred along the eastern margin of Laurentia during the Early Paleozoic.
(Hint: a plate boundary formed.)
Results? (2)
Development of convergent boundary along the eastern margin during Ordovician.
Results:
1. Plate of oceanic crust of Laurentia was subducted
2. Iapetus Ocean eventually closed
3. volcanic island formed
4. Collided with Laurentia
What was the Taconic Orogeny?
Caused by?
Where is it visible today? (3)
- First episode of mtn. building along the Appalachians
- Caused by the collision between the North American Plate and an ancient oceanic plate that subducted beneath it.
Results (3) of the Sauk sequence
Global rise in sea level.
Result:
-Flooding of continental shelves,
-Epeiric seas
-Lots of sediment deposited
Active Margin vs Passive Margin
Active margin- active plate boundary
Passive margin- no active plate boundary, only sediment deposition
