1. Diversity of Life

2. Origin of Life Oparin Theory – Urey/Miller Experiment
ABIOTIC SYNTHESIS OF POLYMERS

4. Go to Notes

5. History of Life

7. The Origin of Life
To account for the origin of life on our earth requires solving several problems:
How the organic molecules that define life, e.g. amino acids, nucleotides, were created?
How these were assembled into macromolecules, e.g. proteins and nucleic acids, — a process requiring catalysts.
How were these able to reproduce themselves?
How these were assembled into a system delimited from its surroundings (i.e., a cell).

8. Theories to Answer These Questions
Abiotic Synthesis of Polymers – see notes for details
1. Polymers were synthesized from inorganic compounds in the atmosphere (Urey Miller Experiment)
2. rained down on earth from outer space (Meteor analysis)
3. were synthesized at hydrothermal vents on the ocean floor (H gas)

9. Urey Miller
In the years since Miller's work, many variants of his procedure have been tried. Virtually all the small molecules that are associated with life have been formed:
17 of the 20 amino acids used in protein synthesis, and
all the purines and pyrimidines used in nucleic acid synthesis.
But abiotic synthesis of ribose — and thus of nucleosides — has been much more difficult.

10. Problem…
it is now thought that the atmosphere of the early earth was not rich in methane and ammonia — essential ingredients in Miller's experiments.

11. Life from Space The Murchison Meteorite
Australia on 28 September 1969, turned out to contain a variety of organic molecules including:
purines and pyrimidines
polyols — compounds with hydroxyl groups on a backbone of 3 to 6 carbons such as glycerol and glyceric acid. Sugars are polyols.
amino acids and their relative proportions were quite similar to the products formed in Miller's experiments.

12. Deep Sea Vents
Some deep-sea hydrothermal vents discharge copious amounts of hydrogen, hydrogen sulfide, and carbon dioxide at temperatures around 100°C. These gases bubble up through chambers rich in iron sulfides (FeS, FeS2). These can catalyze the formation of simple organic molecules like acetate. (And life today depends on enzymes that have Fe and S atoms in their active sites.)

13. 3. Origin of Self-replicating Molecules
The discovery that certain RNA molecules have enzymatic activity provides a possible solution. These RNA molecules — called ribozymes — incorporate both the features required of life:
storage of information
the ability to act as catalysts

14. In the lab, the ribozyme serves as both:
the template on which short lengths of RNA ("oligonucleotides" are assembled following the rules of base pairing and
the catalyst for covalently linking these oligonucleotides

15. Natural Selection in RNA World
In principal, the minimal functions of life might have begun with RNA and only later did
proteins take over the catalytic machinery of metabolism and
DNA take over as the repository of the genetic code.

16. Several other bits of evidence support this notion of an original "RNA world":
Many of the cofactors that play so many roles in life are based on ribose; for example:
ATP
NAD
FAD
coenzyme A
cyclic AMP
GTP

17. PROTOBIONTS

18. Liposomes

19. 3 domains

20. Classification and Taxonomy
Taxonomy = field in bio. that classifies organisms according to presence or absence of shared characteristics to trace evolutionary relationships
5, 6 or7 kingdom (breaks down Monera and Protista more specifically)

21. Autotrophic Bacteria

22. These heterotrophic bacteria digest oil -- remember oil is partially decayed plant and animal cells

23. Nutrition and Growth Oxygen = Death Ex. Clostridium tetani – Tetanus
Heterotrophic or Autotrophic
Some are Photoautotrophs – Use sunlight for Energy
Some are Chemoautotrophs.
Many are Obligate Anaerobes.
Oxygen = Death
Ex. Clostridium tetani – Tetanus
Some are Faculatative Anaerobes
With or without Oxygen
Ex. Escherichia Coli
Some are Obligate Aerobes
Ex.) Mycobacterium tuberculosis
Temperature requirements
Some are Thermophilic, Some prefer acidic envmt.

24. Kingdom Archaebacteria
First discovered in extreme environments
Methanogens: Harvest energy by converting H2 and CO2 into methane gas
Anaerobic, live in intestinal tracts
Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea.
Thermoacidophiles: Live in acid environments and high temps.
Hot Springs, volcanic vents

25. Kingdom Eubacteria Bacilli – rod-shaped Spirilla – spiral-shaped
Can have one of three basic shapes
Bacilli – rod-shaped
Spirilla – spiral-shaped
Cocci – sphere-shaped
Staphylococci – grape-like clusters
Streptococci – in chains

26. BACTERIA PICS

27. Proteobacteria

28. Spirochetes, Chlymydias

29. Gram Stain Have thicker layer in cell wall. Phylum Shape Motility
Gram-positive retain stain and appear purple
Have thicker layer in cell wall.
Gram-negative do not retain stain and take second pink stain instead.
Phylum
Shape
Motility
Metabolism
Gram reacion
Cyanobacteria
Bacilli, Cocci
Gliding, some non-motile
Aerobic, photosynthetic autotrophic
Gram-negative
Spirochetes
Spirals
Corkscrew
Aerobic, and anaerobic; heterotrophic
Gram-Pos
Bacilli, cocci
Flagella; some non-motile
Aer/anaer.; heterotrophic, photosynthetic
Mostly gram-positive
Proteobacteria
Bacilli, cocci, spiral
Aer/anaer.; heterotrophic, photosynthetic autotrophic

30. Protista Endosymbiotic Theory

31. Fungus-like

33. Animal like
Amoeba Rhizopoda

34. Foraminifera

35. actinopoda

36. Plant-like
dinoflagellates

37. diatoms

38. Brown algae

40. Red algae