Biology Notes - Introduction Scientific Method-bio means life-ology means the study of-because biology is a science it is studied using the

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Introduction- Scientific Method -“bio” means life -“ology” means the study of -because biology is a science it is studied using the scientific method which is divided into 5 steps: 1. Make an observation -usually put in the form of a question Ex) Why do vines grow on trees? 2. Make a hypothesis = an answer to the observation = an explanation of the observation -usually includes the word “because” Ex) Vines grow on trees because they use the trees for support only 3. Make a prediction = the hypothesis put in a testable form -usually in the form of an “if…then” statement -only one hypothesis, but many predictions Ex) If vines are grown on sticks then they will grow the same as compared to vines grown on trees 4. Run an experiment -this is the step that differentiates science from other ways of figuring out how the world works -guidelines to running experiments: a. Should be controlled = 2 groups of specimens: -experimental group and controlled groups which will be the same in all variables except for one variable, which is called the independent variable Ex) Vine experiment: Same= soil, pot size, temperature, light, length of support structure, water, same vine species Different= stick vs. tree for support -So it is possible to know which variable is causing the changes b. Avoid sampling error -occurs when too few specimens are used; i.e. individual variations can override the effects of the independent variable; to avoid this many specimens should be used so that individual variations can be averaged out c. Avoid experimental/ human error Ex) Mis-measure a variable, mis-record data -to avoid, do the experiment multiple times d. Identify the dependent (responding) variables = that which changes because of the independent variable; i.e. it is what’s measured to see if the independent variable has an effect Ex) Vine experiment: how long the vines are -many measurements are taken during an experiment= data which is plural -when data is recorded several guidelines should be followed: i. Data is recorded in metric units ii. Data should be recorded as precisely as possible using appropriate instrumentation Ex) ruler iii. Avoid preconceived ideas when recording data Ex) Mendel sorted his peas based on his idea of how the results should end up -to avoid the influence of preconceived ideas, use blind studies iv. When taking data instruments which enhance our abilities should be used, including: Microscopes - magnifies microscopic objects so they become macroscopic -types: o Light microscopes
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-most common -use visible light -maximum magnification possible = 2,000X o Electron microscopes -big, use electrons -2 types SEM - scanning electron microscope -looks at entire specimen -3D -magnifies~ 100,000X TEM - transmission electron microscope -looks at slices made through a specimen -2D -magnifies~ 200,000X Cell Culture - technique used to make microscopic cells macroscopic -uses petri dish and agar (hard jello) Fractionation - technique used to separate out parts of a substance by grinding using
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This note was uploaded on 02/22/2010 for the course BIOLOGY honors taught by Professor Floyd during the Spring '09 term at Saint Marys College Indiana.

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Biology Notes - Introduction Scientific Method-bio means life-ology means the study of-because biology is a science it is studied using the

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