Origin Of Earth Flashcards
Origin of the Earth Theories
- Gaseous Mass Hypothesis of Kant
- Nebular Theory of Laplace
- Planetesimal Hypothesis of Chamberlain and Moulton
- Tidal Collision Hypothesis of Jeans and Jeffreys
- Electromagnetic Theory of Dr. Hannes Alfvén
- Inter-stellar Dust Hypothesis of Otto Schmidt
are pieces of evidence of organisms that lived in the past
Fossils
They can be actual remains like bones, teeth, shells, leaves, seeds, spores, or traces of past activities such as animal burrows, nests, and dinosaur footprints, or even the ripples created on a prehistoric shore.
Fossils
Types of fossils
- molds
- casts
- petrified
- original remains
- carbon film
- trace/ichnofossils
Impression made on a substrate = negative image of an organism
Molds
Example of molds (fossil)
Shells
Type of Fossils
When a mold is filled in
Casts
Type of fossils
Organic material is converted into stone
Petrified
Examples of casts (type of fossil)
Bones and teeth
Examples of petrified fossils
Petrified trees & coal balls (fossilized plants & their tissues, in round ball shape)
Preserved wholly (frozen, trapped in tar pits, dried/desiccated inside caves in arid regions or encased in amber/fossilized resin)
Original remains
Examples of original remains
Woolly mammoth, amber from baltic sea region
Carbon impression in sedimentary rocks
Carbon film
Examples of carbon film (fossils)
Leaf impression on the rock
Type of Fossils
Record the movements and behaviors of the organism
Trace/ichnofossils
Six ways of Fossilization
- unaltered preservation
- permineralization/petrification
- replacement
- carbonization/coalification
- recrystalization
- authigenic preservation
Ways of Fossilization:
Small organism or part trapped in amber, hardened plant sap
Unaltered preservation
Ways of Fossilization
The organic contents of bone and wood are replaced with silica, calcite or pyrite, forming a rock-like fossil
Permineralization/Petrification
Ways of Fossilization
Hard parts are dissolved and replaced by other minerals, like calcite, silica, pyrite, or iron
Replacement
Ways of Fossilization
The other elements are removed and only the carbon remained
Carbonization/Coalification
Ways of Fossilization
Hard parts are converted to more stable minerals or small crystals turn into larger crystals
Recrystallization
Ways of Fossilization
Molds and casts are formed after most of the organism have been destroyed or dissolved
Authigenic preservation
Way that can help a scientist establish its position in the geologic time scale and find its relationship with other fossils
Dating the Fossils (Relative Dating & Absolute Dating)
Dating the Fossils:
It is only based upon the study of layers of rocks and does not tell the exact age.
Relative Dating
Dating the Fossils:
Determines the actual age of the fossils using radioactive isotopes like carbon-14 and potassium-40
Absolute Dating
Rules of Relative Dating:
When sedimentary rock layers are deposited, younger layers are on top of older deposits
Law of Superposition
Rules of Relative Dating:
Sedimentary rock layers are deposited horizontally. If they are tilted, folded, or broken, it happened later.
Law of Original Horizontality
Rules of Relative Dating:
If an igneous intrusion or a fault cuts through existing rocks, the intrusion/fault is YOUNGER than the rock it cuts through.
Law of Cross-cutting relationships
GEOLOGIC TIME SCALE:
The largest division of the GTS which spans hundreds to thousands of millions of years ago
Eon
GEOLOGIC TIME SCALE:
division in an era that spans time periods of tens to hundreds of millions of years
Era
GEOLOGIC TIME SCALE:
Division of geologic history that spans no more than one hundreds of millions of years
Period
GEOLOGIC TIME SCALE:
The smallest division of the geologic time scale characterized by distinct organisms
Epoch
GEOLOGIC TIME SCALE:
- 4.8 million years
- about 88% of the Earth’s history
Precambrian
GEOLOGIC TIME SCALE:
Age of Early Life where soft-bodied creatures like worms and jellyfish lived in the world’s oceans
Precambrian
GEOLOGIC TIME SCALE:
Precambrian consists of what eons
- Hadean
- Archean
- Proterozoic
GEOLOGIC TIME SCALE:
- Earth coalesced from a cloud of dust into a planet
- Formation of Earth
- High temperature
- Ball of gasses
Hadean
GEOLOGIC TIME SCALE:
- Molten rocks cooled down
- Gasses provided cooler atmosphere
Archean
GEOLOGIC TIME SCALE:
It is when early life first appeared on Earth
Archean
GTS:
Our oldest fossils date to roughly ______ years ago and consists of ______________
3.5 billion
Bacteria microfossils
GTS:
Colonies of photosynthetic bacteria which have been found as fossils in Early Archaean rocks of ______ and ______
South Africa, Western Australia
GTS:
These are layers of calcium carbonate that form warm, shallow seas by the activitie of photosynthetic bacteria
Stromatolites
GTS:
Eon when temperature have cooled down significantly and when cyanobacteria existed (w/out oxygen) and oxygenated the Earth
Proterozoic
GTS:
Oldest fossils of larger, multicellular, soft-bodied marine animals
Ediacara fauna
GTS:
Era that is approximately 541.0 million years ago
Phanerozoic
GTS:
Consists of the five major extinction events that is part of the reasons that shifts in Earth’s environmental conditions which made it difficult for some species to survive
Phanerozoic
GTS:
Eon that is also known as “Visible Life”
Phanerozoic
GTS:
Era that started more than 540 million years ago and it is when the first surge of life from the first fish to the evolution of land-dwelling organisms happened.
Paleozoic Era
GTS:
- Burst of diversity
- Hard external skeletons protected trilobites, clams, snails, and sea urchins from predators.
Cambrian Explosion
GTS:
- Invertebrates filled the oceans
- straight-shelled cephalopods, trilobites, snails, brachiopods, and corals in a shallow inland sea
Ordovician Period
GTS:
Plants colonized the land for the first time and was the “golden age” of cephalopods and brachiopods (a clam-like shellfish)
Ordovician Period
