Chapter 1Biology, Scientific Process, and Tools

ObjectivesApply the Scientific Method to Solve a problem.

List the Characteristics of Living ThingsCompare a Hypothesis and a Theory

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

INTERACTIVE

• Prove it has the first 3 characteristics of life…• Copy and complete the table:

Characteristic of Life Organism Proof

Cells and Organization

Stimulus

Homeostasis

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• Succession—the process by which a biological

community evolves over time– Primary Succession—a lifeless area has to evolve

(example after a lava flow)– Secondary Succession—a community is removed (but

not entirely, some life, soil remains) and begins again (extinction of a species, weather related disasters)

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

INTERACTIVE

• Is it alive?• Martian and the Car

Characteristics of Living Things

• Complete the graphic organizer and put it in your notebook.

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??

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 better than middle school

students.• Dogs will run faster after eating a bone.• Bounty paper towels can hold more water

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 plant growth under different colors of light. He is going to expose the same type of plants to yellow, green, blue light, and sunlight.

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

Recording and Analyzing Results

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

• Statistical Variability– how spread out the group of data is. Data sets with very similar numbers have little variability. Data sets with a wide range would be highly variable.

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.

• Scientists will answer their original questions, confirm or reject their hypothesis, and often create new questions

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.

Hypothesis vs. Theory

Hypothesis

• Educated guess• Not tested yet

or• Not tested

much

Theory

• Well-accepted answer

• Well-tested• Supported by

many experiments

Mythbusters and the Scientific Process Mythbusters Episode: Identifying the Steps of the

Scientific Method and possible sources of Error!

1.Watch the episode of Mythbusters.2.While watching, fill in the steps of the Scientific

Method and the possible sources of error.3.Create a Mini-Board

Scientific Method in Action!

Honors:Penny Lab!

Med Bio:Science and Medicine!

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)

Microscope Lab

Metric System

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

• Called SI or Metric System• Metrics Lab!

Vocabulary

Create a flash card for the following terms:

1. Biology2. Cell3. Tissues4. Organelle5. Biological molecule6. Scientific Method

7. Hypothesis8. Theory9. Control10. Independent Variable11.Dependent Variable12.Observation13.Compound Light

Microscope14.Metric System