Biology CH1 - Biology CH1 | Evolution the Themes of Biology...

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Biology CH1 | Evolution, the Themes of Biology, and Scientific InquiryInquiring About LifeAn organism’s adaptations to its environment are the result of evolutionFor example, the seeds of the dandelion are moved by wind due to their parachute-like structuresEvolutionis the process of change that has transformed life on EarthBiologyis the scientific study of lifeBiologists ask questions such asHow does a single cell develop into an organism?How does the human mind work? How do living things interact in communities?Life defies a simple, one-sentence definitionLife is recognized by what living things doConcept 1.1: The study of life reveals common themesBiology is a subject of enormous scopeThere are five unifying themesOrganizationInformationEnergy and matterInteractionsEvolutionTheme: New Properties Emerge at Successive Levels of Biological OrganizationLife can be studied at different levels, from molecules to the entire living planetThis enormous range can be divided into different levels of biological organizationEmergent PropertiesEmergent propertiesresult from the arrangement and interaction of parts within a system Emergent properties characterize nonbiological entities (a thing with distinct and independent existence) as wellFor example, a functioning bicycle emerges only when all of the necessary parts connect in the correct wayReductionism is the reduction of complex systems to simpler components that are more manageable to studyFor example, studying the molecular structure of DNA helps us to understand thechemical basis of inheritanceTo explore emergent properties, biologists complement reductionism with systems biology, analysis of the interactions among the parts of a biological system Structure and FunctionAt each level of the biological hierarchy we find a correlation between structure and function
The Cell: An Organism’s Basic Unit of Structure and FunctionThe cell is the lowest level of organization that can perform all activities required for lifeEvery cell is enclosed by a membrane that regulates passage of materials between the cell and its environmentA eukaryotic cellhas membrane-enclosed organelles, the largest of which is usually the nucleusBy comparison, aprokaryotic cellis simpler and usually smaller, and does not contain a nucleus or other membrane-enclosed organellesTheme: Life’s Processes Involve the Expression and Transmission of Genetic InformationWithin cells, structures called chromosomescontain genetic material in the form of DNA(deoxyribonucleic acid)DNA, the Genetic MaterialEach chromosome has one long DNA molecule with hundreds or thousands of genesGenesencode information for building the molecules synthesized within the cellGenes are the units of inheritanceDNA controls the development and maintenance of organismsEach DNA molecule

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