BIO 326R 1st Edition Lecture 1 Outline of Current Lecture I. Earth Historya. Earth beginsi. Meteorites1. Isotope ratiosb. Life beginsi. Fossil recordsii. Stromatolitesc. Great Oxidation Eventd. Evolution of eukaryotese. Animalsf. HomosapiensII. Microbiology Historya. Leeuwenhoekb. Pasteurc. Redi These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current Lecture- Earth formed approximately 4.6 bya (billion years ago)o We have this approximation because Earth formed by a bombardment of meteorites and oldest one found was 4.6 billion years old Isotope ratios were studied in meteorites- Uranium degrades to lead in 4.5 bya- Life begins 3.5-3.8 byao Fossil records of single celled organisms found Stromatolites= cross sectioned rock of fossil records—observed chains of single cellso 3.8 bya in C12/C13 ratios, materials were found with higher carbon 12 ratios Photosynthesis prefers C12 Materials with higher C12 ratio shows evidence of photosynthetic cellslife- Great Oxidation Event 2.4 byao The photosynthetic micrrobes started creating oxygen- Evolution of Eukaryoteso Fossil records show 1.6 byao Bio markers show 2.1 bya- Animals arrived .6 bya- Homosapiens arrived 200K years agoHistory of Microbiology- 55 BCo A poem served as evidence of someone who thought microbes made you sick- 1693o Leuwenhoek= first person to look at bacteria under a microscope Used cells from moutho Humans carry 10^14 bacteria on body and humans have 10^13 eukaryotic cells in the body 10 x’s more bacteria, but eukaryotic cells are MUCH largero Leuwenhoek also experimented with bacterial cells when you smoke, drink, don’tbrush your teeth- Pasteuro Swan neck flask Used for disproving spontaneous generation- Spontaneous generation= forming of living things from nonliving things Put mean in swan neck flask, boiled the meant to kill bacteria, tested meat for bacteria, no bacteria grew- Shape of swan neck flask trapped any dust particleso Redi disproved spontaneous generation before Pasteur Put meat in three flasks (covered with cap, gauze, or nothing) and observed which had maggots- No maggots on flask with cap- Maggots on gauze- Maggots on meat of open
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