Introduction to Biology The Study of Life

What is Science? Science is an organized way of gathering and analyzing evidence about the world. There are universal laws that apply to all objects in the universe, small or large, living or nonliving.

The goal of science is to Provide explanations for events in nature To understand patterns To make useful predictions

Science never stands still. New discoveries raise new questions. Science aims for the best understanding that current methods can reveal.

Science begins with making observations which involve noticing and describing events. Scientists use the information they gather to make inferences. These are logical interpretations based on prior knowledge.

The Scientific Method Steps: 1. Observe and ask questions 2. Infer and form a hypothesis 3. Design a controlled experiment a. controlled variables-may be deliberately changed. These are called the independent variable or manipulated variable. b. The variable that responds to the independent variable is called the dependent or responding variable

c. the control group is carried out under normal conditions d c. the control group is carried out under normal conditions d. The experimental group is done the same as the control group except for the dependent variable

The information we gather is called data There are two main types: Quantitative which is expressed in numbers Qualitative which involves descriptions and can’t be counted. Data can then represented in some visual way such as a chart, graph or diagram

Graphing Rules: Independent variable is known or predetermined. it is placed on the bottom of the graph Dependent variable is the unknown it is placed on the side of the graph

An understanding of science is important in making intelligent decisions about life. Science can make recommendations but society makes the final decisions.

follow the teacher and lab handout instructions exactly! Lab Safety The most important rule in a lab is: follow the teacher and lab handout instructions exactly! If in doubt, ask questions.

Class labs: No goofing around Keep glassware from edges of tables No food or drink in lab area Always clean up your own area

Lab tools 1. Dissection tray-pan for holding animal while dissecting. Filled with wax to stick pins in.

2. Eye dropper-used for small amounts of liquid 3. Triple beam balance-determines the mass of an object

4. Metric ruler-measures length of objects 5 4. Metric ruler-measures length of objects 5. Dissection scissors-for cutting, have a short blade

6. Probe-for probing inside animal 7. Forceps-picking up small items 8. Scalpel-cutting

9. Petri dish-circular dish for growing bacteria

10. Test tube rack-holds several test tubes upright 11. Test tube-for growing bacteria

12. Microscope-magnifies very small objects

13. Slide-rectangle shaped glass for putting object on to view under microscope 14. Cover slip-square of thin glass to spread out object so light can go through it

15. hand lens-magnifying objects that are too big for a microscope.

16. Beaker-holding materials, mixing, heating--never for measuring 17 16. Beaker-holding materials, mixing, heating--never for measuring 17. Graduated cylinder-accurately measures liquids

18. Thermometer-measures heat in an object

19. Goggles-protects eyes from splashes from harmful chemicals 20. Bunsen burner-for heating materials

The Metric System Most experiments include measurements. (quantitative) Experiments must be able to be repeated so scientists use a common measuring system called the metric system.

Basic units of measuring: mass-grams

Length-meter

Volume-liter

Temperature Scales Fahrenheit Celsius Water boils Body temp Room temp Water freezes

Prefixes for units: Milli = .001 Centi = .01 Deci = .1 1 Deka = 10 Hecto = 100 Kilo = 1000

Rule to change from one to another: When you go up you multiply by 10 and move the decimal to the right. When you go down you divide by 10 and move the decimal to the left.

Characteristics of living things: Made up of cells Able to reproduce Based on the genetic code-DNA Grow and develop Obtain and use energy (Metabolism) Respond to their environment Maintain a stable environment (homeostasis) Groups of living things change over time (evolve)