Name _______________________________________ Date ________________________ Period _____
History of Life (SB5b: Explain the history of life)
1) How has life on earth changed since Earth was first formed?
Essential
Questions
Where did life on earth come from?
Abiogenesis:
A: ______
Bio: ________
Genesis: __________
Abiogenesis: the theory that _____________________________________
Abiogenesis = spontaneous generation: life grows without other life (example: rats
grow from garbage)
Biogenesis:
Bio: ______
Genesis: ___________
Biogenesis: the theory that ______________________________________
Experiment to test biogenesis vs. abiogenesis
 Louis Pasteur boiled broth to ______________________
 He put a neck on the beaker so _____________ could get in but
____________________________ could not
Predict: Do you think bacteria would grow?
 Results: __________________ could grow without other life!
Think: Which theory does this support?
 This supports the _______________ theory because life did not grow without life
already there
How did life form?
 Urey-Miller experiment: simulated earth’s _______________________ and added
electricity
 Found that _________________________________________ formed
Name _______________________________________ Date ________________________ Period _____
Early Earth
Vocabulary Review
Aerobic Anaerobic Prokaryote –
Eukaryote -
 Earth formed ____________ years ago
 The first organisms formed ____________ years ago

The early Earth’s environment had no ___________
Think
Do you think the first organisms would be aerobic or anaerobic?
Do you think the first organisms would be prokaryotic or eukaryotic?
 The first organisms were: ______________ and _________________
 _______ billion years ago, there was __________ in the atmosphere
 ___________ organisms developed
 ______ billion years ago, ____________ developed

Scientists believe that ___________ became the _____________ and ___________
of eukaryotes
Fossils
 Fossils: _________________________________________________
 Absolute dating: scientists tell ________ how old a fossil is by studying
________________________________________
 Relative dating: scientists tell which fossil is oldest by
__________________________
o oldest fossils are ____________________________________
A geologist finds fossils in each of the undisturbed rock layers. The fossils are all structurally similar.
Which is the most likely conclusion that the geologist would make?
a) All fossils are of the same age
A
b) The relative ages of the fossils cannot be determined
B
c) The fossils in rock layer D are older than those in layer A
d) The fossils in rock layer B are older than those layer C
C
D