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Explore the organized way of gathering and analyzing evidence in biology. Learn about the scientific method, controlled experiments, data analysis, and the characteristics of living things.
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Biology Science – an organized way of gathering and analyzing evidence about the natural world. • Examples: • Biology – • Goals of science: • Provide natural explanations for events in the natural world • Use explanations to understand patterns in nature and make predictions about natural events.
5 steps of the Scientific Method • Observing and asking questions • Inferring and forming a hypothesis • Designing and carrying out a controlled experiment • Collecting and analyzing data • Drawing conclusions
Scientific method • Observing and asking questions • Observation: act of noticing and describing events or processes in a careful, orderly way. • Inferring and forming a hypothesis • Inference: logical interpretation based on what scientists already know • Hypothesis: scientific explanation for a set of observations that can be tested in ways that support it or reject it.
Designing controlled experiments • Controlled experiment: one in which only one variable is changed at a time. All other variables are controlled. • Ex. Changing the liquid (water, soda and OJ) used to water plants but the amount of sunlight is the same. • Control group: exposed to same conditions as experimental groups except for one independent variable.
Variables • Independent variable: variable that is deliberately changed • Dependent variable: variable that is observed and that changes in response to the independent variable Example on graph on next slide…
3 important things you must have on a graph: • Title • Labeled axis • Units
Collecting and analyzing data • Data: information • Quantitative: numbers by counting or measuring • Qualitative: descriptive • Tools used to collect • Journals/ computer • Graphs and charts • Drawing conclusions
Scientific Theory • Applies to a well tested explanation that unifies a broad range of observations and hypotheses. • Ex. Evolution, cell theory • No theory is considered absolute truth – law • Theories may be revised or replaced by a more useful explanation
Characteristics of Living Things • Living things: • Are based on a universal genetic code • DNA
Living things: • Grow and develop • Cell division and differentiation
Living things: • Respond to their environment • Stimulus – signal to which an organism responds
Living things: • Reproduce • Asexual – single organism produces offspring • Sexual – 2 parent cells unite to form new organism
Living Things • Maintain a stable internal environment - Homeostasis
Living things: • Obtain and use material and energy • Metabolism – sum of all chemical reactions
Living things: • Are cellular – made up of at least 1 cell • Smallest unit of life
Living things: • As a group – evolve – change over time