1. Warm Up On the note card ▫Write your name. ▫Your favorite topic about last semester. ▫The things you did best last semester. ▫Your grade last semester. ▫What do you hope to be different for this semester. ▫What do you hope to improve on this semester. ▫What is your goal for this semester.

2. Evolution Unit Notes #1: The Earth’s History

3. 3 Experiments for vital force: 1) Redi – do flies come from meat? Spontaneous generation: early idea that life could be produce from non-living substances using vital force Vital force: an invisible substance in the air that could give rise to new life from the nonliving world 2) Spallanzani – does vital force produce life in water (straight necked flask)? 3) Pasteur – does vital force produce life in water (curved necked flask)?

4. Measuring the Earth’s Age Radiometric Dating = calculating the age of an object by measuring proportions of radioactive isotopes Radioactive Isotope = an unstable form of an element that decays into simpler elements and gives off energy (radiation) Ex/ Carbon-14 decays into Nitrogen & Potassium-40 decays into Argon-40 Half-life = the amount of time it takes for one half of a given radioactive isotope to decay (specific to the substance) Potassium 40 Half-life = 1.3 billion years Argon 40 ~4.5 billion years old

5. 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 Testing the idea: 1920 – Oparin & Haldane suggest early atmosphere contained organic molecules & lacked oxygen 1953 – Miller & Urey test the primordial soup model

6. Vocab Take a sheet of paper and fold into 3 columns. Column 1: Vocab Word Column 2: Definition in 8 words or less. Column 3: Picture ▫If there is no picture. ▫Draw and example or ▫Draw something that relates. TODAY’S VOCAB (DUE TUES) Biogenesis Spontaneous Generation Isotope Atom Microspheres Coacervates Radiometric dating

7. HW: Get an 8.5 x 11 inch 3 subject notebook. Go on Mr. E’s website at www.losal.org/lahs and use instructions to make a cover page for Unit 8.www.losal.org/lahs ▫Due Wednesday Read p282 – 286 answer #1-5 on p.286

8. 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. Cyanobacteria were some of the first prokaryotes to show and they were photosynthetic Cyanobacteria began adding oxygen to the atmosphere through photosynthesis Today 21% of the Earth’s atmosphere is oxygen

9. Eukaryotes from Prokaryotes Eukaryotes show up in the fossil record 1.5 billion years ago The Theory of Endosymbiosis One of the main differences between prokaryotes and eukaryotes= Mitochondria & Chloroplasts Proposes that these organelles are the descendents of symbiotic, aerobic eubacteria. Later a photosynthetic prokaryote entered a symbiotic relationship with a larger cell The larger host cell would gain protection from toxic oxygen Supporting Evidence: Both organelles contain their own circular DNA and can replicate on their own.