Chapter 1

ObjectivesApply the Scientific Method to Solve a problem.

List the Characteristics of Living ThingsUnderstand Homeostasis

Compare a Hypothesis and a Theory

Vocabulary

Create a flap book for the following terms:• Hypothesis• Theory• Succession• Statistical Variability• Controlled Test• Observation

INTERACTIVE

Quickwrite:

In your own words, What is Biology?

Biology

The Study of LIFE

INTERACTIVE

• What makes something alive???• Think, discuss, pass the pen

Characteristics of Life

• Biologists have established that all living things share 7 Characteristics of Life.

Cells Stimulus Homeostasis

Metabolism Growth and Development Reproduction

Change through Time

Organization and Cells• All living organisms (one celled or multicellular)

have some degree of organization.• CELL—smallest unit of life• UNICELLULAR—one celled organisms• MULTICELLULAR—made up of more than one cell• Complex Multicellular organisms (such as

humans) have ORGAN SYSTEMS, groups of parts that carry out specific functions.

• ORGANS are structures that carry out specialized jobs within an organ system.

Organization and Cells• All organs are made up of TISSUES, or groups of

cells with similar functions.• Tissues are made up of CELLS.• ORGANELLES are within each cell and are tiny

structures that carry out functions necessary for the cell to stay alive.

• Organelles contain BIOLOGICAL MOLECULES, the chemical compounds that provide physical structure, movement, energy.

• Biological Molecules are made up of ATOMS, the simplest particle of an element.

Organism

Organ Systems

Organs

Tissues

Organelles

Biological Molecules

Atoms

Response to Stimuli

• An organism can respond to a STIMULUS or physical/chemical change in the internal or external environment.

• Example—an owl dilates its pupils to keep the amount of light entering the eye constant and therefore maintain good vision.

Homeostasis

• The maintenance of a stable level of internal conditions even though the environment is changing.

• Examples: Maintaining body temperature, water content, nutrients within a cell

• GOLDFISH LAB

INTERACTIVE

• Observing Homeostasis with Goldfish!

Metabolism• Living organisms use ENERGY to repair, move, and

grow.• Metabolism is the sum of all the chemical reactions

that take in and transform energy and materials from the environment.

• Example—plants use the sun’s energy to generate sugar molecules through photosynthesis.

• Example—an owl’s metabolism allows the owl to extract chemicals in its prey and use it as energy to fuel growth.

Growth and Development

• All living things grow and increase in size.• Living things grow from the results of divisions

and enlargements of cells.• Unicellular—enlargement of cells• Multicellular—division of cells• Development is the process by which an

organism becomes a mature adult.

Reproduction• All living organisms produce new organisms in a

process called reproduction.• Reproduction (unlike the other characteristics is

NOT essential for life of a single organism, however it is essential for the continuity of the species)

• During reproduction organisms transmit hereditary info to their offspring. This info is encoded in DNA (deoxyribonucleic acid).

• A short segment of DNA contains instructions for a single trait (like eyecolor), this is called a GENE.

Reproduction

Sexual Reproduction

• Hereditary info recombines from 2 organisms of the same species.

• Results in similar (but not identical to parents) offspring.

Asexual Reproduction

• Hereditary info is not recombined

• The offspring and the original organism are essentially the same (genetically)

• Example—a bacterium reproduces when it splits into two identical cells.

Change through Time

• Basic genetics do not change through time• Populations of living organisms evolve or

change through time to survive

Song—Characteristics of Living Things• Which characteristic is missing??

INTERACTIVE

• Is it alive?

Science as a Process

• Science is characterized by an organized approach…the SCIENTIFIC METHOD.

• Quickwrite…What do you know/remember about the Scientific Method??

Scientific MethodObservation/

Question

Hypothesis

Experiment

Data/Results

Conclusion

Observations

• Science starts with observation– Observation involves using the 5 senses to gather

information– Can be quantitative (numbers) or qualitative (not

numerical, more descriptive)– All of this information is gathered as DATA, or

evidence– What are the 5 senses??

INTERACTIVE

• Guess What Activity

Interpreting the Evidence

• Scientists must make inferences based on the observations.

• Inferences are a logical, unbiased, interpretation based on prior knowledge, experience, and observation

• Examples of Inferences:– You see a broken window and a baseball laying on

the floor under the window. You INFER that the baseball broke the window.

INFERENCE - a logical interpretation based on prior knowledge

* Drawing a conclusion

Explaining the Evidence

• A HYPOTHESIS is a possible explanation or answer to a scientific question.

• A Hypothesis must be TESTABLE.• Examples:1.  Purina food will reduce a dog's shedding.

 

2.  Putting Miracle Grow on tomato plants will make them produce more tomatoes.

 

3.  The drug Avapro will lower a person's blood pressure.

 

Examples of HypothesesExamples

Good BadPlants will grow taller with Miracle Grow.

Plants will grow better when given Miracle Grow.

Girls will score higher on math tests than boys.

Girls are smarter than boys.

Hermit crabs will choose colorful shells over plain shells.

Hermit crabs like colorful shells.

INTERACTIVE

• Write a hypothesis for the experiment below:– A scientist is going to measure toy car speed on a

ramp. He is going to test if the size of the wheel affects the speed of the toy car going down a ramp. He has a regular toy car, a toy car with extra large wheels, and a toy car with mini-wheels.

– What is your hypothesis??

Identify the GOOD hypothesesCopy the good hypotheses and explain why it is

good.• Plants will grow taller with sunlight.• Boys like video games.• 9th graders are smarter than middle school

students.• Dogs will run faster after eating a bone.• Bounty paper towels are stronger than the

store brand.• Cats are good mouse hunters.

Setting up a Controlled Experiment

• A controlled experiment is a test of a hypothesis with only one variable being tested.

• Manipulated (Independent) Variable is the part of the experiment that is being deliberately changed by the scientist.

• Responding (Dependent) Variable is the part of the experiment that that changes as a result of the experiment.

• Controlled Variables: items that stay constant throughout the experiment (example: the materials used)

INTERACTIVEA scientist is going to measure toy car speed on a ramp. He is going to test if the size of the wheel affects the speed of the toy car going down a ramp. He has a regular toy car, a toy car with extra large wheels, and a toy car with mini-wheels.

What would your hypothesis be??What would the Manipulated/Independent Variable be??What would the Responding/Dependent Variable be??

INTERACTIVE 2

• Your group will be given a scenario. • Read it aloud.• Answer the questions your notes.• When time is up, rotate the scenarios and

repeat.

Recording and Analyzing Results

• Scientist keep written records of all observations and data, often in a journal, notebook, or computer.

Error• No experiment is perfect. Many things can go wrong and many things cannot be controlled.

• Scientists acknowledge that there will be error.

• Scientists ALWAYS identify and communicate sources for error.

Sources for Error…

Human Error Instrument Error

Environmental Materials not uniform

Drawing a Conclusion• Scientists then use the data and results from an

experiment to evaluate the original hypothesis and develop a conclusion.

• Look at pages 14-15 in your textbook, study the pictures and captions on the Owl. Be ready to answer the following:– What was the question?– What was the control?– What was the variable?– What was the conclusion?

Publishing

• If evidence supporting a hypothesis builds up from many, many experiments by many scientists, the hypothesis becomes a THEORY.

• A THEORY is a well-tested explanation or answer to a problem.

INTERACTIVE

• Can your procedure be replicated??

Hypothesis vs. Theory

Hypothesis

• Educated guess• Not tested yet

or• Not tested

much

Theory

• Well-accepted answer

• Well-tested• Supported by

many experiments

INTERACTIVE

• Quickwrite: In your own words explain the difference between Hypothesis and Theory.

Tools and Techniques

Light Microscope

• To see small organisms and cells scientists usually use LIGHT MIRCROSCOPES.

• A compound light microscope has 2 lenses to magnify an image.

• 4 major parts to a light microscope:– Eyepiece– Objective lens– Stage– Light Source

Magnification and Resolution

• Magnification– The increase in the objects apparent size

• Example: 10x means 10 times the objects real size.

• Resolution: the power to show details clearly (how focused it is)

Electron Microscope

• To examine cells in great detail or study cell parts or viruses, scientists use Electron Microscopes.

• Very powerful magnification and resolution.• Always in black and white (computers can add

color)

Metric System

• Scientists use a common measuring system so they can compare and understand results.

• Called SI or Metric System

Base UnitsBase Quantity Name Abbreviation

Length Meter M

Mass Kilogram Kg

Time Time S

Electric Current Ampere A

Thermodynamic Temperature

Kelvin K

Amount of Substance Mole Mol

Light Candela cd

More Units

Assessment

• Chapter Review, pages 25-27