Bio; Lecture 02; Life

Bio; Lecture 02; Life - Principles of Biology 2 What is...

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Principles of Biology 2 BIOU103 1-10-07 What is life? Other planets o Mars Has life existed on Mars? There is evidence of the past existence of water flow on the surface of mars NASA’s Spirit rover—probe sent to Mars Searched for signs of water—ultimately signs of life Images suggest present-day sources of liquid water on Mars o Titan Saturn’s moon White streaks in photo suggest evidence of liquid flowing on the surface of Titan Definition of Life o Living things share these characteristics: Highly structured and organized Made up of cells ( Cell Theory) Grow and develop from an immature form to a mature form Require energy intake Photoautotrophs : acquire energy from sun and make sugar Chemoautotrophs : absorb chemicals (nutrients) from environment Heterotrophs : ingest food for energy Can respond to environmental stimuli Can adapt Reproduce Maintain homeostasis in spite of living in a changing environment Homeostasis : stable internal environment o Cell theory All living organisms are made up of cells Some are made up of only one cell: unicellular Some are made up of many cells: multicellular All chemical reactions of any living organism take place within the cells Cells arise from other cells They contain the heredity information which is passed to the next generation Modern cells evolved from first primitive cells o Attributes of life at different levels Cellular level Most attributes of life apply at this level - 1 -
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Principles of Biology 2 BIOU103 1-10-07 Individual level Not everyone can reproduce, not all are well adapted, not all respond to stimuli (paraplegics) Species level Most attributes of life do apply Earth level (GAIA) Most attributes of life do apply GAIA: organisms and their material environment evolve as a singled coupled system. Earth does not stay the same
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Bio; Lecture 02; Life - Principles of Biology 2 What is...

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