Lecture Notes 2

Lecture Notes 2 - The History of Life 2/18/2008 4:21:00 PM...

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The History of Life 18/02/2008 15:21:00 The problem with understanding the history of time We often have trouble differentiating 2 far off times (ex. 100 MYA and 1BYA)  even thought very different things were happening at these times Tips for understanding the history of life Know the when and the what… Have a understanding of what the names refer to… o Animal?  Mammal? Arthropod? Protist? Prokaryote? Know the BIG events…  Keep an eye on the Tree…(next slide)  Note: You should treat all dates here as approximations! Age of Earth: 4.6 B.Y. Early Earth: 4.6-4.0 B.Y.A. Characterized by huge space impacts (meteors, etc.) Lots of volcanism  The moon hit the earth during this time and started orbiting Earth became habitable - 4.0 B.Y.A. Water and primitive atmosphere Continents present but would be unrecognizable No free oxygen
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First forms of life – 3.7 B.Y.A. Bacteria like organisms – the first forms of life that  we could see , there could  have been other life that we just don’t have evidence of Stramatolite fossils   o Looks like a wavy rock or coral (when it is alive) because of a bacteria  shield over the rock. o Keeps on growing until the bacteria on the inside mineralize and turn  into rocks Scientists used to think life on other planets was impossible but the biologists  not think that it is almost certain there is o Explored our own planet and have seen the diverse environments  organisms live in. o Since we’ve been alive, hundreds of planets outside our solar system  have been discovered Bacteria: the Prokaryotes: 3.7-2.0 B.Y.A. Bacteria are characterized by having a certain type of cell organization and  biology which we call Prokaryotic.  Refers to the biology of a cell. Dietary bacteria o Our digestion is hinged on bacteria o No animal on our planet can get energy from plants.
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o Animals such as cows depend solely on the bacteria for digestion Biotechnology o Using bacteria for technology o Ex. Spraying bacteria after an oil spill o Waste product plants Nitrogen fixation o Most important organism on our planet. They change nitrogen into  something we can use o No animal can use atmospheric nitrogen (N2) o Bacteria are stored in plant stems – we get our nitrogen from the plants  or from animals that eat those plants. o
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This note was uploaded on 04/16/2008 for the course BIOS 10107 taught by Professor Filchak during the Spring '08 term at Notre Dame.

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Lecture Notes 2 - The History of Life 2/18/2008 4:21:00 PM...

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