Chapter 1 – The Science of Biology Edwin P. Davis, M.Ed.

What is Science ? Science is an organize way of using evidence learned about the natural world. The goal of science is to investigate and understand the worlds around you with explanations that make predictions about events in the natural world.

What is Science? The basic approach to research in science is called observation. An observation is the process of gathering information about events or processes in a careful & orderly manner.

What is Science? Inferences are logical interpretations based on prior knowledge or experience. Inferences allow scientist to predict possible outcomes to experiments or observations based on their accurate observations or academic or professional experiences.

Interpreting Evidence Scientist explain events in nature by using logical and analytical approaches called an Hypothesis. A hypothesis is a proposed scientific explanation for a set of observations.

The Scientific Method A scientific method is a well organized set of investigation procedures used by scientist according to a specific pattern or protocol. The scientific method is an organized plan for gathering, organizing, and communicating information with others.

6 Steps in the scientific method Ask a question Form a hypothesis Test the hypothesis Analyze the data Draw a conclusion Repeat the experiment

Step One Ask a question: Asking a question helps identify what type of problem is to be solved.

Step Two Gather Information – People usually gather information about a particular event through the use of encyclopedias, scientific journals, textbooks, internet, and other sources.

Step Three Form a Hypothesis: A hypothesis is a possible scientific explanation for a problem by using what you know and observed. A hypothesis is a proposed answer to a question.

Step Four Test the Hypothesis Hypothesis are usually tested through experiments, observations, and model building.

Step five Interpreting the data and analyzing the observations is an important step. If the data are not organized in a logical manner, wrong conclusions can be drawn

Step six Based on the analysis of your data, you decide whether or not your hypothesis is supported. For the hypothesis to be considered valid and widely accepted, the experiment must result in the exact same data every time it is repeated.

Experimental Variables A variable is any factor in an experiment that can change. A independent variable - (Manipulated) is a factor you change in an experiment to determine the affect on the dependent variable. A dependent variable (responding) is a factor that changes as a result of changes in other variables.

Experimental Controls A controlled experiment is an experiment in which all the variables are kept unchanged. Controlled experiments are used to test only one variable at a time in an experiment.

Variables The independent variable is typically the variable representing the value being manipulated or changed. The dependent variable is the observed. The dependent variable is the variable that is being measured in an experiment

A control is the standard by which the test results can be compared. Constants and Controls A factor that does not change when other variables change is called a constant. A control is the standard by which the test results can be compared. Plant Amount of Water Amount of Sun Fertilizer Type Height after two weeks A 4 oz. every three days 6hr/day 16cm B 14cm C 18cm D none 10cm 17 17

Controlled Experiment: An experiment in which an observer tests a hypothesis by looking for changes brought on by alterations to a variable.

Interpret predict to give or provide the meaning of; explain to declare or tell in advance; prophesy; foretell: to foretell the future; make a prediction.

Replicate folded; bent back on itself. bend or fold back: to repeat, duplicate, or reproduce, especially for experimental purposes. something that is replicated, as an experiment or procedure

Analyze : to examine critically, so as to bring out the essential elements or give 

spontaneous generation abiogenesis, the hypothetical process by which living organisms develop from nonliving matter; 

What is an observation? A. When you observe, you become aware of something using one of your senses. Your five senses are smell, taste, sight, touch, and sound. I an observation you simply describe something as it appears. An observation is a statement describing a fact.

Parts of an Orange

Parts of an Orange

Observation In the space below, record 5 observations about your science classroom. 1. 2. 3. 4. 5.

Qualitative Observation B. Sometimes scientists must make very careful observations. Often their senses are not good enough. There are some things that cannot be observed using just your senses. (Examples: radiation, sound waves, planets, cells, etc.)

Can you think of ways that scientists have solved this problem Can you think of ways that scientists have solved this problem? How can scientists extend their senses? Microscopes, Telescopes, satellites, etc.

What is an inference? A. When you infer, you make a mental judgment based on observations. Inferences cannot be directly observed. They require thought. For example, if you get up in the morning, look up at the sky and observe dark clouds, observe the air is cool and humid, and observe puddles on the ground, you might infer that it has recently rained. Note: you did not see rain; you decided that it rained based on your observations. An inference is a statement based on your interpretation of the facts.

List 3 inferences about the classroom 1. 2. 3.

Inference Vs. Observations Inferences That plant is extremely wilted due to a lack of water. The car stooped running because it was out of gas. The sox are leading there division because they are playing well right now. Observations That plant is extremely wilted. The car stopped running The Sox are leading there division

More examples What observations can we make about this picture? What can we infer based on this picture?

What observations can we make from these pictures?

Inference Vs. Observations

Inference Vs. Observations

Tracks in the Snow Observation 1 Observation 2 Observation 3

7 Characteristics of Living Things Essential Question: “What makes something living?”

1. Cell Theory Theory in biology that says all living things are composed of cells All cells must come from other cells Does not support abiogenesis Schleiden and Schwann

2. Reproduce Reproduce one of two ways 1) asexual – no mating required 2) sexual – requires two parents

3. Based on a genetic code Either has DNA and/or RNA Determines the organisms characteristics

4. Grow and Develop Unicellular – usually just increase in size Multicellular – most go through stages of development

5. Use materials and Energy Take in nutrients and materials to grow Process of using materials and energy is called metabolism Plants use energy from the sun to produce food (photosynthesis)

6. Respond to their environment Respond to a stimulus (something which causes a reaction) in their environment to change Can be external or internal

7. Maintain internal balance Homeostasis – internal balance inside an organism pH, temperature, water levels

- Light Microscope - Electron Microscope Tools of Biology - Light Microscope - Electron Microscope

Light Microscope Most commonly used Can produce clear images of objects at 1000X Compound light microscope uses two lenses to form an image (we will use these)

Compound Microscope

1. Eyepiece 3. Arm 4. Nosepiece 5. Stage Clips 6. Objectives 9. Stage 10.Coarse Adjustment Knob 11.Diaphragm 12. Light Source 13. Fine Adjustment Knob 14. Power Switch 15. Base

Electron Microscope Transmission Electron Microscope Passes electrons through a specimen Cholera Algae Sea Urchin

Electron Microscope (con.) Scanning Electron Microscope Sends beams of electrons across the surface to “map” surface of specimen Cholera Ant Sea Urchin Cells

M I C R O S C O P E S Microscope Types: Before Microscopes: sick because cursed or punished for bad deed Microscope Types: Simple light – 1st type 1 lens Energy Source light LOW magnification power 2. Compound Light 2+ lenses Energy source light Lens= 10 Objective = 4 Total Magnification = 40 Up to about 1500 X’s Electron Microscopes Uses beam of electrons Magnify up to 500,000 X’s M I C R O S C O P E S Microscope  tool used to look at small organisms Micro – small Scope – to look at Microscopes allow US to see cells! Cell basic unit of life SEM scanning e-microscope surface TEM transmission e-microscope inside

Simple Light Microscope

Compound Light Microscope

SEM – Scanning Electron Microscope

TEM - Transmission Electron Microscope

Match the part with the letter Parts: Objectives, Diaphragm, Lens, Coarse Adjustment, Light Source, Arm, Stage, Fine Adjustment Fine Adjustment E. Stage Lens F. Diaphragm Light Source G. Objectives Coarse Adjustment H. Arm Answer Questions using Parts 1. __D__Used to bring objects into rapid focus first 2. __F__ Regulates the amount of light going through slide 3. __H__ Used to carry the microscope 4. __E__ Supports the slide 5. __A__ Turned to clear blurry pictures Answer Questions: How do you carry a microscope?- by the arm If the lens is 10 and the objective is 4, what is the total magnification?- 40

What Is Magnification on a Microscope? Definition - Magnification on a microscope refers to the amount or degree to which the object observed is enlarged. It is measured by multiples, such as 4x, 10x and 40x, indicating that the object is enlarged to twice as big, four times as big or 10 times as big, respectively.

Total Microscope Magnification Total Magnification = Objective Lens X Eyepiece