Chapter 2 The Science of Biology

Science = to know Based on inquiry What is science? Science = to know Based on inquiry Inquiry – asking questions about observations in nature and actively seeking answers

Observation – use of the senses to gather and record information about structures or processes in nature

Data – recorded observations Quantitative data – observations recorded as measurements Qualitative data – observations in the form of descriptions

Ex. Human Genome Project Some discoveries are accidental Discovery Science Discovery Science – science that describes natural structures or processes as accurately as possible through careful observation and data collection Ex. Human Genome Project Some discoveries are accidental Ex. Alexander Flemming (Penicillin)

Inference – Logical conclusion based on observations Often use prior knowledge Help to refine general questions – more specific Generalizations – general conclusion Ex. All living things are made of cells

Hypothesis-Based Science Scientific method - an organized approach to help understand how the natural world works

Scientific Method Steps 1. Observation Act of perceiving a natural occurrence that creates questions

Scientific Method Steps 2. Hypothesis Used to answer question(s) by proposing an explanation (use “if…..then” statements)

Scientific Method Steps 3. Prediction Statement that forecasts what would happen in a test situation if the hypothesis were true

Scientific Method Steps 4. Experiment Controlled tests Control group – a group that serves as a standard of comparison with another group

Experimental group – the group that contains the independent variable Independent Variable – the factor that is manipulated Dependent Variable – factor that changes in response to the independent variable

Scientific Method Steps 5. Collect and Analyze data Gather data from experiment and evaluate state if hypothesis and prediction are supported/true Evidence – collected body of data from observations and experiments

Scientific Method Steps 6. Conclusion/Publishing State if hypothesis and prediction are supported and true based on data analysis Theory – explanation of some phenomenon that has been tested to be true several times

Model – physical, mental, or mathematical representations of how people understand a process or an idea Ex. 3-D object, graph, equation, drawing Allow work to be analyzed by scientific peers/public. Work is reviewed and critiqued

Technology (applied science) Applying scientific understanding for some specific purpose Ex. Engineering, biotechnology

Tools and Techniques Microscope – tool that visually enlarges an object Light Microscopes Light that passes from an object through a lens is bent so that the object looks either larger or smaller Lens – piece of glass that has been shaped to bend light

Simple microscope – only one lens Ex. Magnifying glass (magnify 10x) Tools and Techniques Simple microscope – only one lens Ex. Magnifying glass (magnify 10x) Compound microscope – 2 or more lenses

Ocular lens – found in eyepiece Objective lens – found on nosepiece Each objective lens has a different magnification

Tools and Techniques Total magnification = Ocular x Objective Ocular lens (10x) Objective lens (4x, 10x, 40x) Ex Low Power 10x X 4x = 40 Midrange 10x X 10x = 100 High Power 10x X 40x = 400 Parts of a Microscope

Resolution – measure of how clear an object appears Tools and Techniques Resolution – measure of how clear an object appears As magnification increases, resolution decreases

Field of view – Area of light that is seen when looking through a microscope As magnification increases, field of view decreases Amount of light is controlled by diaphragm Parfocal – microscope stays in focus as objective lenses are changed

Tools and Techniques Electron Microscopes Powerful microscope that uses tiny negatively charge particles called electrons to magnify objects Can magnify up to 300,000x Resolution can be up to a million times better than the human eye Very expensive

Units of Measurement Metric System (the international system of units) Standard system of measurement scientists use to compare results Based on the powers of “10”

Mass – amount of matter an object has Units of Measurement Mass and Weight Mass – amount of matter an object has Weight – amount of matter + pull of gravity Gram (g) – basic unit of mass Tool for measurement - balance

Units of Measurement Length Length – measure of distance between two points Meter (m) – basic unit of length Tool for measurement – ruler, meterstick

Units of Measurement Volume Volume – amount of space an object takes up Liter (L) (Quart)– basic unit of volume Tool for measurement – graduated cylinder/ beaker/flask/pipette

Fahrenheit and Celsius Units of Measurement Temperature Temperature – measure of how hot or how cold an object/substance is Fahrenheit and Celsius 0ºC - 32ºF Freezing 100ºC - 212ºF Boiling 22ºC - 72ºF Room Temperature