The Origins Of Life

1. The Origins Of Life By Aaron Hebson Can Feng Nya Smith

2. Formation of Earth and the Moon • Giant Impact Hypothesis: • 4.56 billion years ago a Mars sized planet named Theia collided with young earth • Disintegrated mantles of both planets, and the debris formed into Earth’s moon • Evidence: Lunar rocks rich in sodium, potassium, zinc, and lead which is a result of the vaporization • If vaporization did not occur, lunar rocks would be composed of heavy isotopes • HOW THE MOON FORMED!! • http://dsc.discovery.com/tv-shows/other-shows/videos/other-shows-how-the-universe-works-videos.htm

3. Heavy Bombardment • Started around 4.1 billion years ago and ending around 3.9 billion years ago • A hypothesis that states a influx of planetary bombardment of comets and asteroids • It was an essential for developing large plants, and were expected to give the plants in our solar systems most of there mass • A hypothesis predicts that the cause of this bombardment was due to the planetary migration of the large gas planets • This caused the asteroid and comets the orbited around them to continuously collide with terrestrial planets

4. Earth’s Cooling • Occurred in the Hadeon eon, around 4 billion years ago • Water vapor was formed by collision of large terrestrial bodies • Comets and asteroids that collided with earth contained large amounts of ice • Condensation of this water vapor formed the oceans we know today

5. Stromatolites • Time period: 3.5-2.5 billion years ago • Sheets of microbial collect sedimentary particles and undergo photosynthesis • Pillow-like rock formation formed as a byproduct • Proliferation of cyanobacteria soon followed allowing for excess oxygen in atmosphere

6. Primordial Soup • The organic soup model hypothesizes by Miller/Urey suggested that life began from a combination of chemicals resulting in monomers • These monomers were created through some energy source, such as lightning • This organic soup of monomers can then be used to make more complex molecules

7. Hydrothermal Vents • The Deep Vent Model suggests that life formed in hydrothermal vents • These vents are formed when two geographical plates move apart, releasing lava into the ocean • This lava heats the ocean providing safe havens for life to form • Monomers could be present in these vents to sustain life

8. Meteorites • The Solid Reactive Surface Models suggests that organic materials used to create life came from meteorites and comets • These organic materials would be deposited onto the earth’s surface, and later used to create complex beings

9. Monomers- Nucleotides • Nucleotides are simple organic molecules • Composed of one phosphate, a pentose sugar, and a nitrogenous base • These monomers are used to build nucleic acids • The acids can be used for various functions in life such as storage, transfer of vital information, and even enzymes

10. Monomers- Fatty Acids • Monomers used to construct fat through the combination of the fatty acid and glycerol • A long carbon skeleton ending with carboxyl groups • The carboxyl group may differ from each other in their functional group, designating the name of the acid • Extremely hydrophobic

11. Monomers- Phospholipids • Similar to fats except only two fatty acids are attached to the glycerol • Phosphate and Choline groups are attached to glycerol to form hydrophilic head • Fatty acids are remain hydrophobic • Phospholipid bilayer is formed in aqueous solutions, resulting in a membrane

12. Monomers- Micelle • A structural form of phospholipid bilayer in an aqueous solution • Hydrophilic heads form around the fatty acid chains forming a small sphere

13. Monomers- Vesicle • A small bubble that forms inside a cell • Enclosed by a phospholipid bilayer • Can form naturally such as endocytosis or exocytosis • Used to organize cellular function, transport, metabolism, etc.

14. Protocells • Aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure • Exhibit certain properties of life such as a simple reproduction and metabolism

15. Formation of Nucleotides • Abiotically with the help of clay • Miller/Urey’s experiment also showed that an influx of energy could cause the creation of nucleotides

16. RNA Hypothesis • RNA First Hypothesis states that RNA played a significant role in protein synthesis and catalytic functions • Most likely formed due to it’s diverse descendants, mutations, and reduced uniformed structure

17. Ribozymes • RNA functioning as catalysts • Make complementary copies of RNA • Remove segments from themselves • Excising other molecules

18. DNA in Cells • DNA formation: one theory suggests that RNA organisms made DNAs.

19. Evolution of Cells- Endosymbiosis • Primitive prokaryotes engulfing: aerobic prokaryote (mitochondrion) photosynthetic prokaryote (chloroplast)

20. Multi-cellular Organisms First multicellular organism: 1.2 bya, small algae.

21. Cambrian Explosion • Around 500 MYA • Sudden Appearance of phyla animals during the first 20 million years of Cambrian period

22. K-T Event • Around 230-65 MYA • Cretaceous-Tertiary Extinction Event occurred • Thought to of occurred by a large asteroid or increased volcanic activity

23. Homo erectus • Homo sapiens evolved from Homo erectus about 200 TYA • Mass Inhabitation (We’re awesome)