2. Formation of earth and origin of life Flashcards
What is a protoplanetary disk
rotating cloud of dust and rocks made in the big band
When was thr protplanetory disk destroyed?
4.6 bilion years ago in the supernova
How was the sun created
the protoplanetary disk accelaterated, heated up a
How were protoplanets formed
small colliding objects that remained in the disk
How were planets formed
smaller objects collided to form larger objects
What eons are in the Precambrain super eon
Hadeon eon, archeon eon
what did earth look like during the hadeon eon
- no free oxygen, hydrogen and helium gas, molten, no protective atmpsphere
How was the atmosphere created?
it was bombarded by asteroids that released steam and gas
What did the early atmosphere consist of
ammonia, methane, nitrogen, hydrogen
what was the archaeon eon
when unicellular life arose
What was early life
stromatolites, bacteria and archea
how long ago did unicellular life arise
3 billion years ago
what eon did multicellular life arise
prechambrian, Archean
what was the first multicellular life
trilobites, hard shell animals
how long ago did multicellualr life arise
1 billion years ago