UNIT 1 Science of Biology NOTES Fill in

UNIT 1 – Science of Biology NOTES • Fill in packet during discussion. • Be ready to make concept and vocabulary list.

Topic 1 A: Characteristics of Living Things

BIOLOGY– The study of life Living things are known as organisms. The living world and the non-living world are mixed. As you look out the window here at school or as you investigate any environment you will find a mixture of the two. How can we identify something as an organism? For each of the items listed below state a reason that makes it living or non-living: Clouds Mushrooms Worm Fire Automobile

What characteristics do all living things share? 1. Living things are made up of units called cells • Some organisms are made of only one cell and some are made of trillions of cells. • Cells are small self-contained units of living material that are separated from the surroundings by a barrier.

Unicellular – organism made of only one cell Multicellular – organism made of more than one cell. In complex multicellular organisms such as humans, many different types of cells work together to perform the functions needed by the organism.

2. Living things reproduce: Reproduction is the life process that provides for continuation of the species. An individual will not die if it does not reproduce but the species will end if no members reproduce.

Terms to know: Sexual reproduction- requires cells from 2 parents to create a new individual different from each parent. Common in multicellular organisms (trees, birds etc. ) Asexual reproduction – requires only one parent. Offspring is identical to parent.

3. The traits of living things are determined by the genetic code: When organisms reproduce they pass on genetic information in the form of DNA to the offspring. • In sexually reproducing organisms the offspring obtain a mixture of genetic information from each parent. • In asexually reproducing organism the offspring have identical genetic information to the parent

4. Living things grow and develop. Every organism has its own life-cycle – a pattern of growth and change that occurs over the organisms lifetime.

5. Living things obtain and use materials and energy. Examples • Oxygen and sugar are needed by organisms to make energy. • Food is needed to help build the body

Chemical reactions take place in the body to convert the materials from the environment into forms usable by the organism. Metabolism is the collection of all the reaction that take place within an organism. Examples of Metabolic Reactions: • Building Cells • Breaking down cells • Converting oxygen and glucose to energy and carbon dioxide.

6. Living things respond to their environment. Organisms live in a constantly changing environment. Examples: Light, temperature and amount of water change from day to day and season to season. Plants and animals must respond to these changes or they will die.

7. Living things maintain and a stable internal environment. The steady state (balance) inside an organisms body is known as HOMEOSTASIS. While the environment outside changes an organism must be able to keep conditions inside mostly the constant. If homeostasis is disturbed the organism will become sick and will die if the balance is not fixed.

8. Taken as a group, living things change over time Life has changed significantly over the history of the earth. The process of this change is known as evolution.

CHECK YOUR UNDERSTANDING #1: (Complete in Chapter Summary Packet) In essay format discuss what characteristics all living things have in common and how life on earth is different. Be sure to include the following terms in your response in a way that demonstrates an understanding of the term: Organism, unicellular, multi-cellular, sexual reproduction, asexual reproduction, life cycle, metabolism, homeostasis, evolution

Sample Essay Living things (organisms) can be distinguished from non living things by several characteristics and abilities. All organisms are comprised of cells. Whether organisms are made up of a single cell (unicellular) or many cells (multicellular) they are able to carry out similar processes. To continue the species all organisms must be able to reproduce. Some species reproduce by combining genes from two parents in a process known as sexual reproduction. Some species reproduce asexually and produce a genetically identical offspring. All organisms carry on chemical reactions in their body, called metabolism, that allow them to maintain a state of homeostasis or internal balance. Over time, life on earth has evolved to include these common characteristics, but life has developed many different ways of accomplishing these processes.

Topic 1 B: The Scientific Process What is Science? Science comes from a Latin word which means “to know” Therefore, Science is a way of knowing…. It is what we use to answer a question about the natural world

Science is all about inquiry. People ask questions about nature and what they observe and then actively seek to find answers. The process of finding answers is known as the Scientific Method.

The scientific method has brought us the technology we enjoy today. These inventions are not the result of any one discovery but the total knowledge collected over centuries of scientific inquiry.

The steps of the Scientific Method? 1 -Define the problem (What’s the Question) What are you trying to find out? What just happened? Why does it do that?

Write 2 questions about the natural world which you have wondered about? Examples of questions: Why do pigeons bob their heads when they walk? Why do leaves turn color in the fall?

2 -Formulate a Hypothesis- A possible explanation for an observation that can be tested. Example: Pigeons bob their heads because it helps them see better.

3 -Testing the Hypothesis. Experimentation Finding a procedure to either verify or disprove the hypothesis Hypothesis is accepted only when predicted effects are observed and repeatable

A. Experiment design is critical to make experiment and hypothesis accepted Controlled Experiment- Situation is set up more than once to test your hypothesis • Variable- A single factor in the experiment is changed to see if this has an effect on the results • Control group- One group in the experiment where no change is made.

Characteristics of a well designed experiment: • The sample size is large enough to draw a valid conclusion about the hypothesis • Only one significant variable is tested through the experiment. • A control group is present • Conclusions must be based on measurable quantities or clear criteria and not subject to opinion of the observer.

The dependent variable is the one that changes is response to the other variable. The independent variable is the one that causes the change the other variable.

In investigating questions where one factor (variable) is dependent on another, phrase the tests as: The effect of __________ on ______________. Or _______________ depends on ___________

Example The effect of rain amount on oak tree growth. The growth of the tree depends on the amount of rain. Therefore we call the growth of the tree the dependent variable and the amount of rain the independent variable.

In the relationships below circle the dependent variable and underline the independent variable. (look for things that can be measured) 1. People gain weight based on the amount of calories they take in. 2. The amount of sunlight available influences how fast a tomato will ripen. 3. The amount of television watched by children impacts attention span

In general the dependent variable is plotted on the yaxis and the independent variable is plotted on the xaxis. Example: Hypothesis – The more time a student spends thinking before blurting out, the less time they spend in the Assistant Principals office. Time in AP office Fill in the dependent and independent variables on the axes below: Time spent thinking before speaking

B. Measuring Variables i. International System Units Measurement Base Unit Basic Tools Length Meter Mass Gram Balance/Scale Volume Liter Seconds Graduated Cylinder Time Temperature Celsius or Kelvin Ruler Stop Watches Thermometer

ii. The Scale of Biology Sub-Units of metric system used in Biology Tools for length Kilo 1000 times Centi 1/100 th Milli 1/1000 th Micro 1/1, 000 th Nano 1/1, 000, 000 Measuring Tape Ruler Light Microscope Electron Microscope

For each of the following organisms listed below choose the appropriate scale of measurement (metric) for scientists to use: • Kilograms Weight of an Elephant _________ Micrometers • Width of a Bacteria ___________ Celsius or Kelvin • Temperature of a liquid ________ Centimeters • Length of a feather __________ Grams • Weight of a feather __________ Meters • Height of a person __________

4 -Analyzing and Drawing Conclusions I. Looking at data obtained in the experiment(Use graphs, charts, pie graphs etc. ) II. Looking for patterns or relationships III. Draw a conclusion about your data (Does the data support your hypothesis or not)

5 -Reporting Observations. Record your data and report in detail your means experimentation and observed results Scientists must report all the details because the experiment has to be repeatable.

Practice Graph Problems A. Baby chicks require a constant source of food. As chicks grow, more energy is required for daily activities. The following table gives the grams of food eaten by a chick over a five day period. Number of Days Graph in packet Food eaten (g) 0 1 2 0. 0 1. 0 3. 2 3 6. 5 4 5 10. 6 15. 4

A water plant placed in bright light gives off bubbles of oxygen. In the lab, it was noticed that if the light were placed at different distances from the plant in the aquarium, the rate of bubbling varied. Plot a graph of the following data. Distance from light 10 Oxygen Bubbles/Minute 40 20 20 30 10 50 3

6. Tying Discoveries Together A. Theories and Laws Theory-Explanations that apply to a broad range of phenomena and that are supported by experimental evidence Scientific Law- Statement that describes some aspect of a phenomenon that is always true

How do you tell the difference between a Scientific Theory and Scientific Law? A Scientific Law relates to a single action • Example: Gravity • A Theory explains a series of related phenomena Example: Evolution Cell Theory

Both theories and laws are well tested and widely accepted. • Parts of theories can be adapted to new discoveries or to make them more understood, but the overall theory will not change. Laws are not flexible but can be put into simpler words. •

Laws and Theories are different then Hypotheses. • Laws and theories are well tested by experimentation. • Hypotheses are educated guesses based on an observation before they are tested.

Remember: All Hypotheses are Valuable: Even if a hypothesis (testable guess) is false it is a valuable tool because it may lead to further investigations.

Topic 1 C: Laboratory Techniques A. Main Techniques used in Biology 1. Centrifugation Materials of different densities suspended in a liquid can be separated by spinning a tube at high speeds 2. Micro dissection Tiny instruments that work on one cell at a time

3. Tissue Culture Maintaining living cells of tissues outside the body (in vitro) 4. Chromatography A technique that separates different substances from each other on the basis of chemical or physical properties 5. Electrophoresis A technique that separates proteins, nucleic acids(DNA), and other substances with an electric current

6. Spectrophotometry Using light to analyze what a substance is and how much is present. “Photo” means - Light 7. Staining – A technique in which a dye is added to make a substance within a cell easier to

8. Microscopy The microscope is perhaps the most important tool in the history of biology. The invention of the microscope opened up the worlds of cells to scientists. The two types of microscopes used in this class are compound microscopes and dissecting microscopes.

Important Microscope Vocabulary Magnification – enlargement of an object 100 X means that the image appears 100 times bigger than the actual object. Resolution – the ability of a microscope to show detail (clarity, sharpness).

Compound light microscope: The compound light microscope brings light to your eye through a combination of lenses that allow you to see small “Micro” sized objects in a magnified form.

To determine magnification you multiply the power of each lens used. 4 (objective) X 10 (eyepiece) = 40 magnification

4 x 10 = 40 X 10 x 40 = 400 X The best compound microscopes can reach a magnification of about 2000 X. Compound light microscopes require light to work. The objects observed in a compound microscope must be thin enough for light to pass through.

Images in a compound microscope appear upside down and backwards. Examples: t Would become t e e

B. How to properly use a microscope: 1. Adjust the microscope to the low power objective and raise the stage to top position. 2. Center the specimen over the light that is coming up through the hole in the stage. 3. Look through the eyepiece of the microscope and adjust light so that it is comfortable for your eyes. 4. Use coarse focus knob until object comes into view and then use fine adjustment to get sharp focus. 5. You may then use higher power objectives with fine adjustment knob only.

Dissecting Microscopes (also known as Stereoscopes): Dissecting microscopes are used to view an image in 3 D format. Images are not inverted or upside down. Dissecting microscopes can not magnify as well as a compound light microscope.

C. Measuring with microscopes The area of the slide that you see when you look through a microscope is called the “Field of View”. • You need to know the size of your field of view to estimate the size of the object. • Use a thin metric rule to determine the size of field of view in millimeters (mm). • Convert millimeters to micrometers using 1 millimeters = 1000 micrometers

Quick trick: just move decimal 3 places to the right Practice the following 1. 3 mm = 1300 micrometers 2. 4 mm = 2400 micrometers. 8 mm = 800 micrometers. 25 = 250 micrometers The symbol for a micrometer is m

Determining field of view when you change power: We can use proportions to determine the field of view when the magnification changes: Low power High power = Low field of view High power field of view Example: If the diameter of the field of view on low power (40 X) is 4000 micrometers, determine the field of view for medium power (100 X)

Example: If the diameter of the field of view on low power (40 X) is 4000 micrometers, determine the field of view for medium power (100 X) 40 X ? = 100 X 4000 m ANS: 1600 m

Estimating the size of an object with field of view: • Calculate the diameter of the field of view for the power of magnification. • Looking through the eyepiece, estimate how many times the object will fit across the field of view. • Calculate the size of the object using the formula below. Size of object = diameter of field of view (in m) Number of times object fits across • Remember to use m

EXAMPLE: The image of the amoeba to the left is seen under medium power (100 X) with field of view 1600 m Calculate size of the amoeba The amoeba would fit across the field of view 2 times. Therefore, the approximate length of the amoeba is 800 m or 0. 8 mm.