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Rules for warm-up

Rules for warm-up. Warm-ups are to be started as soon as the bell rings. One weeks worth of Warm-ups should fit on one side of a sheet of paper. Mr. E will stamp warm-up if you have been working since the bell rang. Warm-ups will be collected every two weeks.

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Rules for warm-up

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  1. Rules for warm-up • Warm-ups are to be started as soon as the bell rings. • One weeks worth of Warm-ups should fit on one side of a sheet of paper. • Mr. E will stamp warm-up if you have been working since the bell rang. • Warm-ups will be collected every two weeks. • Warm up 1/29: Describe the experiments of Redi, Spallanzani, and Pastuer. What were these three scientists trying to show?

  2. Warm up 1/29: Describe the experiments of Redi, Spallanzani, and Pastuer. What were these three scientists trying to show? Evolution Unit Notes #2: The First Organisms

  3. Testing the idea: So how did life begin? (take 2)Spontaneous Origin Spontaneous Origin = the process of life developing from non-living chemical interactions 1) Simple Organic molecules were formed in the atmosphere. (Ammonia, Methane, Hydrogen gas, Water, but NO Oxygen gas) 2) Sun light, volcanic heat, lightning, etc energized the molecules creating larger and more complex substances. The first building blocks of life became available

  4. 1920 – Oparin & Haldane suggest early atmosphere contained organic molecules & lacked oxygen • 1953 – Miller & Urey test the primordial soup model

  5. Prokaryotes, the oldest organisms Scientists study fossils to discover clue of what early life was like Fossils = mineralized bone, tooth, shell or imprints of organisms The oldest fossils are microscopic and date 3.5 billion years old from Australia Early prokaryotes survived without oxygen, in fact oxygen was toxic to some. Cyanobacteriaare some of the oldest prokaryote fossils: they were photosynthetic autotrophs Cyanobacteria began adding oxygen to the atmosphere through photosynthesis Today 21% of the Earth’s atmosphere is oxygen

  6. HW: Classwork: Deep Time Homework: Due Thursday Read p279 – 283 answer #2-4 on p.281 Answer #1,2 on p. 286 Cover Page: Due Tomorrow Don’t Forget a page for your name.

  7. Warm-up 1/30: What comprised the Earth’s early atmosphere? Where the first organisms prokaryotes or eukaryotes? Heterotrophs or Autotrophs? Why? Evolution Unit Notes #3: Eukaryotes & Heredity

  8. Eukaryotes from Prokaryotes Eukaryotes show up in the fossil record 1.5 billion years ago One of the main differences between prokaryotes and eukaryotes= Mitochondria & Chloroplasts The Theory of Endosymbiosis Proposes that these organelles are the descendents of symbiotic, aerobic eubacteria. (mitochondria) The larger host cell would gain protection from toxic oxygen Later a photosynthetic prokaryote entered a symbiotic relationship with a larger cell = chloroplast

  9. The Origin of Heredity Why is RNA needed? Why not go straight from DNA to Protein? Current theories suggest RNA was the first genetic material not DNA Support: RNA can form many shapes RNA can store information as well as act as a catalyst Ribozyme = a RNA molecule with the ability to catalyze a specific reaction ReverseTranscriptase = a ribozyme capable of copying RNA into DNA form which could have helped the transition into cells using DNA These molecules can replicate themselves as well Early cell like structures could have accumulated/collected RNA molecules with different abilities

  10. Radiometric Dating Review

  11. Mr. Eisenberg has a sample 100 grams of Carbon-14 which has a half life of 6,000 yrs. • How much is left after 6,000 yrs?/ 12,000 yrs? • If you find 25 grams of Mr. E’s C-14, How old is the sample?

  12. Mr. Eisenberg has 1000 grams of a highly radioactive isotope with a half life of 90 minutes. • How long until only 1/16 th of the original sample is radioactive? • What happens to the other 15/16th? • Mr. E come in at 8:00 am and finds 20 grams of this substance is radioactive. At what time was 40 grams radioactive? • Answers • 360 Min or 6 hours • It becomes a stable isotope. • 6:30 am

  13. Homework: Due Thursday Read p279 – 283 answer #2-4 on p.281 Answer #1,2 on p. 286 • Homework: Due Friday Read p 284-290 Problems p. 296 #3-5 Problems p. 290 #1-5

  14. Homework Read p.297 – 301 Answer Questions #1,3,6-8 on p301 Quiz Friday covering Monday through today’s notes

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