1. Theories of where life came from
Life Origins
Theories of where life came from

2. Spontaneous generation
Called abiogenesis
The Idea that life can come from Non-Life.
Ex. Mice appear in a jar of grain covered by a dirty shirt
abiogenesis

3. Francisco Redi
Proved that maggots do not spontaneously form on meat

4. Redi’s experiment Open jar  maggots Sealed jar  no maggots
Cloth covered jar (air)  no maggots

5. Spallanzani
Proved microorganisms could not grow without particles from air settling in broth
Open  grew bacteria
Closed  no bacteria

6. Louis Pasteur
Improved Spallanzani’s experiment by using a curved swan neck flask

7. Pasteur's experiment Allowed air, but no dust into broth.
No microorganisms grew
Until he broke off neck

8. So where did life come from?
Theories

9. A - Spontaneous formation in primordial soup
The theory that just the right combination of elements, compounds and energy formed the first biomolecules which then assembled itself into first life
One Time Event

10. B - Panspermia Theory that life is of Extra Terrestrial origin
1) Organic compounds brought on meteor
2) Aliens “seeded” life

11. C – Life Was Created
Creationism - The belief that a supreme being or God created life from non-life in the beginning
Intelligent design - The theory that life is so complex it indicates a designer behind its formation (not necessarily God)

12. Origin of the universe
Big Bang Theory – The idea that the universe all started in the same place and expanded outward

13. Big Bang was 15 Billion years ago (maybe 13 -14 Billion )

14. Evidence of big bang The Universe is expanding. Proved by two things
Red Shift of galaxies
Background radiation of 3 degrees Kelvin

15. 3 degrees Kelvin
Radio telescope (in Holmdel NJ) picked up radio waves emitted from the left over heat energy from the big bang. 1965

16. Red shift
When the lines in a galaxy’s or star’s spectrum shift into the red part of the spectrum, as it moves away.
Shows us that all stars and galaxies are moving away from a central point

17. Solar system formation
Large clouds of gas and dust were pulled together due to gravity. The pressure causes stars to form and ignite.
Planets are made of extra debris left over

18. Solar System
Solar system formation is estimated at 5 billion years ago
The estimated age of earth 4.6 billion years

19. Earth’s atmosphere Came from volcanoes emitting gas
Also may have come from comets

20. Earth’s early atmosphere
Contained NH3, H2, H2O and CH3
Maybe Oxygen? Sunlight releases O2 from H2O
O2 causes oxidation (breakdown) of biomolecules

21. Oparin’s hypothesis
He believed that the early atmosphere contained ammonia, hydrogen gas, water vapor and methane
Warm temperatures and lightning could have caused organic compounds to form

22. Miller – Urey experiment 1953
Tried to recreate original conditions
Formed some amino acids
Problems:
-Too much O2 oxidizes
-Too hot, denatures
Mostly discredited

23. EVIDENCE Possibly Supporting spontaneous origin of life

24. Microspheres 1957
Fox produced tiny microspheres made of amino acids that would reproduce by budding , but DID NOT pass on any genetic information

25. Coacervates
Tiny formations of molecules, mostly lipids, held together by hydrophobic forces.
Maybe these forces held biomolecules together long enough to form life

26. Ribosymes RNA that can act as an enzyme
Would help before proteins first made

27. Cyanobacteria Possibly first photosynthetic bacteria
Produced O2 for atmosphere
O3 (Ozone)

28. Endosymbiosis theory
Mutually beneficial relationship where one prokaryote lives in another forming Eukaryote
Explains why mitochondria and Chloroplasts have DNA