, rierodotus billion
million
years ago-bya
years ago-mya
·universe started 13.)bya-because of the
Big Bang
earth is very old 4.6 by
earth's crust has been built up in
layers successively laid down by water (sedimentary)/ volcanic
activity
-
·
->
each diff age =
oldest at bottom
-allows for fossil record to exist
·dating of fossils relative
dating: comparing to
surrounding layers
-
-radiometric (absolute) dating no. of half lives/radioactive isotopes in rock
-
analysing
a t least extinctions mya= 90% of life disappeared
-
5 mass 250
-65
mya dinosaurs disappeared
stroying bosette about:
you learn
ancient forms (ie: trilobites
·
(individual species taxonomic
·appearance + extinction of
orgs to whole
groups
↳= understand
adaptations + climate
·how life forms changed +
gradually became more similar to present day
·
evidence to support evolution
so rich in
fossils
·earliestors
-
stromatolites (cyanobacterial in Barberton, Mpumalanga
·
primitiveland plants -
eg: Glossopteris in KIN
·coelacanth fish ancestral to amphibians
group
-
mammal-like reptiles bridge bow reptiles + mammals Karoo
· = -
human's earliest direct ancestors Australopithecus africanus + Homoergaster in Sterkfontein Caves (crale of Mankind
· -