1 / 12

Evolution Unit

Evolution Unit. Notes #1: The Earth ’ s History. Origins of Life. “The proper scene for the slow brewing of life from nonlife was the early Earth. The Earth’s conditions favored certain chemical combinations over others, and with the passage of time a direction was set.”

korene
Download Presentation

Evolution Unit

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. Origins of Life • “The proper scene for the slow brewing of life from nonlife was the early Earth. The Earth’s conditions favored certain chemical combinations over others, and with the passage of time a direction was set.” • Lynn Margulis and Dorion Sagan, 1993

  3. Spontaneous Generation & Vital Force • 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

  4. 3 Experiments for vital force: • Redi – do flies come from meat? • Spallanzani– does vital force produce life in water (straight necked flask)? • Pasteur– does vital force produce life in water (curved necked flask)?

  5. The Early Earth

  6. ~4.54 billion years old 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)

  7. 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. 1920 – Oparin & Haldane suggest early atmosphere contained organic molecules & lacked oxygen 1953 – Miller & Urey test the primordial soup model The first building blocks of life became available

  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 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. The larger host cell would gain protection from toxic oxygen Later a photosynthetic prokaryote entered a symbiotic relationship with a larger cell Supporting Evidence: Both organelles contain their own circular DNA and can replicate on their own.

  10. 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 an example or • Draw something that relates. • TODAY’S VOCAB (DUE TUES) • Biogenesis • Spontaneous Generation • Isotope • Atom • Microspheres • Coacervates • Radiometric dating

  11. 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. • Due Thursday Read p282 – 286 answer #1-5 on p.286

More Related