Intro to Biology Notes - BIOL 1308 PDF

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BIOL 1308...

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Intro to Biology A. Process of Science: a. Critical Thinking & Science b. Scientific Method c. Hypothesis Testing & Variables d. Scientific Theories B. Critical Thinking & Science: a. DEF. the deliberate act of evaluating information before accepting or rejecting. b. Hallmark Characteristics of Critical Thinking: i. Skepticism: Question everything ii. Curiosity: Seek evidence; listen to other views iii. Humility: Admit to being wrong C. The Scientific Method: a. Begin with a question on the natural world b. Make observations and review research of others c. Form a hypothesis (testable explanation) i. Make predictions about what should occur if the hypothesis is NOT false d. Test predictions by observation or experiment e. Analyze data to make a conclusion f. Revise hypothesis if rejected; challenge if supported g. Report results to peers D. Hypothesis Testing & Variable Types: a. A hypothesis often focuses on just two variables b. Variables are anything that can vary or be changed i. Qualitative: have different types within categories ii. Quantitative: have measurable numerical values c. Testing involves a prediction of cause-and-effect i. Independent (EXPLANTORY) variable: CAUSE ii. Dependent (RESPONSE) variable: EFFECT iii. Controlled (CONFOUNDING) variable: KEEP CONSTANT d. Hypothesis Testing Approaches: i. Two study approaches (observational or experimental) 1. Control group is unchanged or normal condition 2. Experimental group is manipulated or different ii. Observational Studies: no means for manipulating; group based on inherent differences of subjects iii. Experiments randomly assign groups by manipulation E. Scientific Theory: a. A repeatedly well-tested and supported hypothesis i. Explains a broad range of observations ii. Can be used to make useful predictions about other phenomena b. Opinion and belief are not scientific theory, and may not even be testable hypotheses. F. Overview of Life’s Unifying Properties: a. All organisms share unifying properties i. Order

1. Life begins at the level of a cell ii. Reproduction 1. All life stores information in DNA iii. Growth & Development iv. Sensing stimuli and responding v. Regulation 1. Internal control of functions vi. Homeostasis 1. Steady state internal conditions vii. Energy & Nutrients 1. Are required by all life viii. Adaptation 1. To fit or thrive in their environment G. Order: a. b. c. d. e. f.

All organisms consist of one or more cells Cells are the basic unit of life Cells arise from pre-existing cells Cells are basically the same in chemical composition Cells of very different living things share common functions and structures Order of life extends to more organized living systems, tissues, organs, individuals, and beyond… g. Life’s Levels of Organization: i. Nature has levels of organization ii. Emergent Properties are absent in less organized parts H. Organization Within an Organism: a. Atoms are organized into molecules b. Molecules form cell membranes and cell structures called organelles c. Life emerges at the level of a cell. i. All organisms consist of one or more cells d. In multicell species, cells are organized into tissues, then organs, and then organ systems I. Organization of Groups of Organisms: a. Individual: i. Organs systems function together to maintain conditions needed for all cells (homeostasis) b. Population: i. All individuals of one species in a specific area c. Community: i. All populations in a specific area d. Ecosystem: i. A community interacting with its environment e. Biosphere: i. All regions of Earth that hold life ii. Land, Water, and Atmosphere J. Reproduction: a. All cells have DNA i. Deoxyribonucleic Acid (DNA)

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b. Encodes information necessary for defining the order of life, reproduction, growth, development, regulation, & adaptation c. Copies pass from cell to “daughter” cells in cell division d. Inheritance of traits from parents to offspring in reproduction by DNA e. Asexual: i. Same DNA and traits as parent f. Sexual: i. Two parents contribute DNA; Unique traits Sensing Stimuli & Responding: a. Organisms sense and respond to changes in their external environment to favor survival b. Stimuli may be chemical or physical c. Responses may be positive or negative d. Movement Example: i. Chemotaxis ii. Phototaxis Regulation: a. DEF: the control of the frequency, rate, or magnitude of a biological response to stimuli b. Regulation happens at the cellular level i. Receptor molecules on cell surface sense stimuli ii. Trigger a signal to initiate a cellular respond c. Regulation of responses to stimuli helps maintain homeostasis Homeostasis: a. DEF: the maintenance of an organisms internal environment in response to change externally or internally b. Contribute to keeping all cells, tissues, and entire organisms within their biological tolerance limits for survival c. Mechanisms for homeostasis may be structural functions and behavior Energy & Nutrients: a. All organisms require energy and nutrients to sustain their organization, survival, growth, development, and reproduction b. Energy can be from light or that stored in chemicals c. Organisms can be of two categories: i. Producers: 1. Make their own food from carbon dioxide by photosynthesis or chemosynthesis ii. Consumers: 1. Eat other organisms or the dead organic matter of other organisms Adaptation: a. Adaptation refers to an organism’s “fit” to their environment b. The better the fit, the better survival and reproduction c. Populations of organisms are continuously adapting to their environment d. Adaptation is often slow i. Requires many generations of small genetic changes e. Adaptation involves evolution by natural selection

f. The world of life, past and present, shows great diversity g. Species: One kind of organism h. Classification systems organize species in ever more inclusive groups (taxa) of common lineage. i. Each higher level of taxa has larger numbers of species with unifying similar features. P. Genus and Species: a. Each species has a two-part name, BINOMIAL i. First part: Genus name ii. Combined with the second part, it designated one particular species iii. Proper formatting: Homo sapiens b. Each species is also in a hierarchy of taxa c. The most inclusive taxa, a Domain, is based on common cellular structures and biochemistry Q. Life’s Diversity: a. The world of life shows great diversity b. Many millions of kinds of organisms (species) have appeared and disappeared over time c. Each species is unique in at least one trait—in some aspect of its body form or behavior d. All life falls into one of three Domains R. Domains: a. Current classification groups all species into one of the three domains i. Bacteria: 1. Single-celled prokaryotes ii. Archaea: 1. Single-celled prokaryotes iii. Eukarya: 1. Protists, plants, fungi, and animals 2. All have eukaryotic cells...