lecture 1 brief history of earth Flashcards
when and how did earth form
4.56 billion years ago through rapid condensation of a dust cloud that circulated around the young sun
when are the oldest rocks on the earths surface from
4.3 billion years ago
when did the moon form and earths core seperate
4510Ma
what was the atmosphere 4510Ma
N2 H2O CO2
how old are the oldest lunar rocks
4470Ma
when was the hadean eon and what was it like
4600Ma to 4000Ma
hot fiery, earth is formed here, evidence of some liquid water and a felsic crust
when was the earliest evidence of water erosion (showing presence of hydrosphere)
3800Ma
how was the hydrosphere started
outgassing of volcanos
when where the microfossils of the earliest primative bacteria from
3500Ma
what did the first primative bacteria cause?
the start of the rise in atmospheric oxygen
what where the earliest primative bacteria
hypothermic chemoautotrophs
what did rocks found from 3500Ma show
geo dynamo is operational as rocks showed similar magnetism to today
when where the first banded iron formations formed?
2700Ma
when was continental formation complete
2500Ma
when was the archean eon and what was it like
4000Ma to 2500Ma
crust cooled continent formed, single celled organisms emerged
when did the first multicellular organisms come about
580Ma
what also occured with the first multicelular organisms
oxygen reached 21% of the atmosphere
what and when was the “evolutionary big bang”?
542Ma
8 new branches of the animal kingdom formed
when where the first organisms with shells around
542Ma
when were the first land animals
420Ma
when was the proterozoic eon and what was it like
2500Ma to 541Ma
oxygen but not a lot of life
when were the earliest flowering plants
125Ma
when were the first hominoids
5Ma
when were the first homosapiens
0.2Ma
