Nature of Science: Scientific Inquiry, Methods, Techniques, and History Flashcards
Making observations
–quantitative: can be measure, such as number, length, mass, volume
–qualitative: cannot be measured, color, shape, texture
Formulating and Testing Hypotheses
–a proposed explanation for natural phenomena
Identifying Experimental Variables and Controls
- -experimental variable: can manipulate
- -experimental controls: variables kept constant
Conclusions: proof vs support
- -evidence is not known as scientific proof
- -scientific conclusions and evidence are not accepted as final proven knowledge
Scientific resources & communicating findings
- -findings: maintain accuracy and clarity
- -properly citing, to build new findings
Chemical nature of biology
- -chemistry: study of matter or any physical substance that takes up space or has mass
- -all living things made of matter, all matter made of atoms
- -living organisms made of: C, H, N, O, S, & P
- -biochemistry: study of how these elements combine into biomolecules
- -biomolecules: carbs, proteins, lipids, nucleic acids
- -actions and rxns of the biomolecules drive photosynthesis, cell resp, and digestion
Calculations in biology
–mathematical models: simulate natural phenomena and predict their future
–statistics: summarize and draw conclusions about data in biological experiments
–mathematical biology: inspired by complex biological processes
–theoretical biology: uses data from complex models to develop theoretical assessment of biological processes
Physical Laws and Principles Governing Biological Systems
- -physical biology: understanding natural processes
- -physics: study of matter, energy, and motion
- -includes laws of motion and thermodynamics, and laws of conservation
biophysics: describe and explain patterns in biological processes
Testable nature of hypotheses
- -scientific facts: objective observations not explanations, confirmed by data repeatedly
- -facts accepted as truth, not proof
–hypotheses (proposed and testable) and theories: explanations of natural phenomena
Formulation of theories based on accumulated data
- -hypotheses: tested and confirmed time and time again, data accumulated to be considered theory
- -many sources of evidence needed
- -theory: valid explanation of phenomena
Durability of laws
- -not explanations of phenomena
- -description of natural phenomena
- -distinguished by their durability
- -durability: ability to stay constant over time and their predictive nature
Cell theory and germ theory
Cell theory: all living things are made of cells
–Robert Hooke: used microscope to identify, describe, name cells
Germ theory:
- -Louis Pasteur
- -discovered microorganisms cause food spoilage and disease
- -confirmed cell theory by showing cells come from other cells
Heredity, evolution, and ecology
Heredity: how genes pass thru generations
- -Gregor Mendel
- -observed variation in pea plants by cross breeding plants for specific traits
- -concluded plants get one allele from each parent and one of these will be expressed as trait
Evolution: how sp change over time
-Charles Darwin
Identified driving forces
- -descent with modification
- -natural selection
Both heredity and evolution play major role in ecology
Structure and nature of genetic material
–genetics: studies structure and fn of genetic material as chromosomes and how passed on
Alfred Hershey and Martha Chase
-confirmed DNA has the genetic material
James Watson and Francis Crick
- DNA is double helix
- Rosalind Franklin contrib data to this discovery
Classification of organisms
Biological Classification
- -group organisms based on similarities
- -taxonomy
- -based on hierarchical system by Carl Linnaeus
- -Carl Linnaeus system grouped species
- –Kingdom, Phylum, Class, Order, Family, Genus, Species
- -system modified by Carl Woese
- discovered Archaea
- added Domain
Precision vs accuracy
Precision: how close repeated values are to one another
Accuracy: how close measured value is to true value
Metric and SI units
- -modern form of metric system
- -helps to maintain standards of data across countries
metric system: use metric units
–prefix paired with base unit
SI units: meter (length) kilogram (mass) second (time) ampere (electric current) kelvin (temp) candela (luminous intensity) mole (amt of substance)
Unit conversions
–conversion: changing a metric or SI unit into another metric or SI by multiplying or dividing by a power of 10
–conversion factor: power of 10, indicated by name of prefix
–conversion factor is multiplied for converting to a smaller unit
& divided for converting to a larger unit
Scientific notation and sig figs
–shorthand method of writing very large or small numbers
sig figs: non-zero numbers, zeros bw them, and final zero
the more sig figs the more precise
Linear vs log scales
Linear scale: shows equal values using equal divisions
–explain direct relationships
Logarithmic scale: nonlinear–units written in orders of magnitude or powers of 10
–makes ratio based comparisons for large amts of numbers
Identify patterns and trends in data
Patterns
- -tables, graphs, charts to identify
- -used for patterns with similar or repeated sequences of data
Trends
- -data that moves in general direction
- -requires accurate data
Choose appropriate types of of graphs or charts
Line graphs & Scatter Plots
- -show relationships bw variables
- -record quantitative data
- -independent variable (x)
- -dependent (y)
- -line graphs :large trends
Bar graphs
- -compare data
- -exist in diff categories esp if qualitative data
Histograms
- -similar in structure to bar graphs
- -represent data that can be expressed in ranges of numbers not categories
Pie charts:
- -represent data when expressed as a proportion of a whole
- -data interpreted in comparison with all data collected
Error Analysis
- -systemic errors stem from flaws in data, alters accuracy
- -random errors: unpredictable
- -both types must be accounted for in error analysis
Error Analysis
- -calculates percent error observed in experiment
- -done by comparing results to established value
- -percent error less than 10% is acceptable
Draw conclusions and make predictions
–any errors should be incorporated into conclusions
–scientists analyze data from figures to draw conclusions from the trends and make predictions
Limitations of models
- -Cannot be exact replicas
- -scientists have to use multiple models and modify existing ones for new observations
Select models for a given purpose
–model: description or representation of natural phenomena used to help explain or understand it
–diff models for diff purposes
Physical, conceptual, graphical and/or mathematical models
Physical: physical copies of phenomenon built to scale
-physically visualize processes/phenomena
Conceptual: visual representation of abstract concepts while also describing behavior
Mathematical: describe and predict behavior or phenomena
Graphical: probability and statistics
Molarity and percent solutions
Molarity: measure of a solute or dissolved material in a solution
–used to express percent concentration of that solution
–solutions can be diluted by adding more solvent (the substance in which the solute is dissolved)
Acid and base solutions
–Repairing and using these solutions requires additional safety procedures
Acids: corrosive, must use aprons, nitrile rubber gloves, chemical splash goggles
- -proper ventilation
- -eyewash
- -spill control materials
- -always add acid to water NOT vice versa
- -stored in corrosives cabinet
Bases:
–can be stored same space but physically separated from acids
All prepared and stored solutions must be:
- -labeled with acid
- -concentration
- -hazard warning
- -date prepared
- -review MSDS before disposal
- -always dilute and neutralize acids
Flammable and/or caustic materials
Flammable/caustic: able to destroy organic material
Biological specimens and waste
- -blood, urine, tissue, culture specimens
- -use pipettes or leaf proof containers for biohazards
- -use disinfectants if are infectious materials
- post hazard signs
- -materials must be contained, appropriate materials used
- -materials stored in biological safety cabinets
–biological waste: when dispose must be inactivated by autoclaving or bleach treating within 24 hrs
–inactivated and non biological waste and sharps placed in closed leak proof biowaste container
Optical Equipment
–disperses, concentrates, redirects light using lenses, mirrors, or prisms
–microscopes and telescopes: use objective lenses and eyepiece lenses to magnify
–LASERs: high energy, narrow beams of concentrated monochromatic light
–Spectrometers: measure/record light properties and wave spectrums
Separation Equipment
–separates mixture into distinct separate components
Mechanical separation
- -filtration using funnels or sieves
- -remove large particles from liquid
- -centrifuge: separate mixture at high speeds
Chemical separation:
- -via distillation
- -purifies and separates liquids thru heating and cooling
- -uses burners, tubing, flasks
- -chromatography: separates mixtures by allowing gas or liquid to flow over material
- -components separate as they flow at diff rates
- -use columns, detectors,, pumps
Magnetic separation:
- -magnetic devices to attract and remove magnetic components out of the non magnetic substance in mixture
- -uses separators and columns
Electric Separation:
- -gel electrophoresis
- -uses electrical pulses to separate DNA, RNA, and/or proteins
- -uses power supply, chambers, gel, etc
Measurement, mixing, and heating equipment
- -meters sticks
- -graduated cylinders
- -balances
- -thermometers
- -timers
- -use metric system
- -pH: 14 point scale
mixing lab equipment:
- -pipettes
- -stirrers
heating lab equipment
- -remove all flammable materials
- -Should be AVOIDED: plastic, closed or narrow neck containers (flasks)
- -crucibles: used for heating things at high temps
- -protective clothing and equipment (tongs, hot pads)
Open flames:
- -alcohol burners: low open flames at low temps
- -bunsen burners: higher hotter flames
Other heating:
- -ovens
- -uniformly heat and dry materials
Sterilization Equipment
–effectively remove bacteria that could present a hazard
Small scale sterilization:
–wiping materials with solvent or heating in ovens or over burners
Large scale sterilization:
- -industrial sterilizers
- -autoclaves
Autoclaves: high pressure and temp, reliable
–121 degrees Celsius for 15-20 minutes, up to 30
Use of MSDS or SDS
–chemical cmpds and solutions used in lab must have MSDS or SDS
MSDS contains
- -potential health, fire, reactivity, and environmental hazards
- -instructions for:
- proper and safe prep
- use, storage, handling
- preventative and first aid
Use of PPE
- -minimize hazard exposure and reduce risk of injury/illness
- -must follow OSHA
PPE program must meet:
- identify and address potential hazards
- -select proper PPE based on hazards
- -maintain and monitor use of PPE
–lab aprons, lab coats, made from polyethylene or nitrile for aggressive and caustic materials
–also use gloves and goggles
Use of lab safety equipment
- -use safe chemical storage
- -avoid taking out more materials than need
- -first aid kit
- -fire blankets: grease fire
- -fire extinguisher
- -glass disposal: appropriate bag/box, sealed, dispose
- -above info does not apply to glassware with hazardous material
- -eyewash: 15 minutes
- -emergency shower
