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