READING NOTES - Bio220Readings Chapter 1 Introduction...

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Bio 220 Readings Chapter  1 Introduction: Themes  in the Study  of Life Evolution: the process of change that has transformed life on Earth from its earliest beginnings to the diversity of living organisms today Biology: the scientific study of life Themes of Biology New properties emerge at each level in the biological hierarchy Emergent properties come from interactions of parts as complexity increases Reductionism : The reduction of complex systems to simpler components that are easier to study Systems biology : construct models for the dynamic behavior of whole biological systems Organisms interact with their environments, exchanging matter and energy 2 Major processes in every ecosystem o Cycling of nutrients o One-way flow of energy from sunlight to producers to consumers Energy Conversion: exchange of energy often involves the transformation of energy form one form to another Structure and function are correlated at all levels of biological organization (Form fits function) Cells are an organism’s basic units of structure and function Eukaryotic Cell : subdivided by internal membranes into various membrane-enclosed organelles Prokaryotic Cell (bacteria and archaea): DNA is not separated from the rest of the cell by enclosure in a membrane-bounded nucleus The continuity of life is based on heritable information in the form of DNA Genes : the units of inheritance that transmit info from parents to offspring Each cell has one DNA molecule with many genes. This molecule replicates when the cell divides. DNA controls development and maintenance of the entire organism Double helix arrangement and four different nucleotides (chemical building blocks) form a DNA molecule. Sequence of nucleotides is then transcribed into RNA, which is translated into a specific protein. Genome : the entire ‘library’ of genetic instructions that an organism inherits Bioinformatics : use of computational tools to store, organize, and analyze data that result from high-throughput methods Feedback mechanisms regulate biological systems Negative feedback : accumulation of an end product of a process slows down that process Positive feedback : and end product speeds up its production (e.g. clotting of blood) The Core Theme: Evolution Evolution accounts for the unity and diversity of life Scientists have so far identified and named 1.8 million species Taxonomy : the branch of biology that names and classifies species Three domains: Bacteria, Archaea, Euakrya (first two are only prokaryotic)
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Kingdoms: Prokaryotes, Protista, Plantae, Fungi, Animalia Charles Darwin and Natural Selection “Descent with modification”: evolutionary history of species (unity and diversity) Mechanism for this process: natural selection (individuals with inherited traits best suited to the environment are more likely to survive and reproduce) “Family tree” shows adaptive radiation of new species from a common ancestor (several
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This note was uploaded on 03/31/2010 for the course BISC 220 taught by Professor Mcclure during the Spring '09 term at USC.

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READING NOTES - Bio220Readings Chapter 1 Introduction...

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