Biology. The Science of Biology Chapter 1 1-1 What Is Science?

transcript

Biology

The Science of BiologyThe Science of Biology

Chapter 1

1-1 What Is

Science?

Learning TargetsSections 1-1and 1-2

• Explain the goals of science• Explain what a hypothesis is and give

examples• List and explain the steps of the scientific

method

What is Science?Science: A systematic way of learning about the

world• The goal of science is to….

– Investigate & Understand nature

– Explain events in nature– Make predictions based on

explanations• The goal of technology is…

– to use science to improve our daily lives

What is Biology?• Break It Down:

– Bio: Life or living organism

– Logy: The study of

– Examples of words with Bio- in them? With –logy in them?

Themes of Biology• Two Main Themes of Biology:

– Shared Properties of Living Things/Life•What we will be learning 1st

semester»Biochemistry»Cells»Genetics

– Diversity of Living Things/Life

Diversity of Life

Me, A Scientist?

• Science is asking questions about nature and investigating to try to find “answers”

•Remember: One of our first goals of science was to try to understand nature• Answers are not always achieved, logical

explanations are found• Examples in your life where you may act as a scientist

What Is My Job?

• Scientists seek proof, or explanations for things occurring in nature

• These explanations are often used to build predictions (another goal of science)

– What is the method called that scientists use to come up with these reasonable explanations?

– A series of steps scientists use to help solve a problem

– Can be used by all people and for all problems

– Steps:1. Observations 2. State the problem3. Make a testable hypothesis4. Experimentation- (Designing &

Complete)5. Data- Record and Analyze6. Form a conclusion7. Repeat and publish results

Let’s Create a Mnemonic DeviceThis HAS to be in order:1. O________________2. S ________________3. H________________4. E ________________5. D________________6. C________________7. R________________

1. Observations• Observe the world around

you/sometimes called research– Involves using the 5 senses – Keep an open mind with no

conclusions

• Information gathered from observations is called evidence

Observations, cont’d.• TWO TYPES:

– Quantitative Observation:• Deals with numerical values or a quantity• Example: The dog weighs 55 pounds

– Qualitative Observation:• Usually does not involve a numerical

value but rather a descriptive statement.• Example: The dog is heavy.

1–1– Observations involving numbers are

known as

A)qualitative observations.B)hypothetical observations.C)quantitative observations.D)inferred observations.

Interpreting Evidence

• Inference is a logical interpretation based on prior knowledge and experience.

• Not necessarily based on fact or experimental data.

• Inferences are formed after observations have been made

1–1– A scientist takes paint chips from 10

apartments in a large building. She tests for the presence of lead in the paint and finds it in all 10 samples. She then concludes that lead paint is probably present in all 120 apartments in the building. This conclusion is an example ofA) a scientific fact.B) a scientific error.C) proof.D) a reasonable inference.

Statement Observation Inference

Object A is round and orange.

Object A is a basketball.

Object C is round, black and white.

Object C is larger than Object B.

Object B is smooth.

Object B is a table-tennis ball.

Each object is used in a different sport.

What is Object C?

What type of observations are these?

Soccer Ball

Qualitative

Let’s practice inferences

2. State the Problem

• Identify the problem to study

• Based on observations, curiosity and past experiences

– Ex: Is it living or non-living?

3. Form a testable Hypothesis

• Where do hypothesescome from?– Prior Knowledge– Logical Inferences– Imaginative Guesses

Hypotheses, cont’d.

• Form a Hypothesis:– Attempts to explain the event before facts

are gathered and tested– Must be testable!!!

• Should contain “If” and “Then”

•Ex: If skin cancer is related to ultraviolet light, then people with a high exposure to UV light will have a higher frequency of skin cancer.

Try writing your own hypothesisUse the following problem to come up with a

hypothesis and write it down in your notes.

Problem: The leaves on one of your house plants are turning yellow. The plant gets plenty of sunlight and water, but it is located in front of a drafty window where it gets very cold.

4. Experimentation

• Determine if the hypothesis is correct– Repeat experiments many, many times– Accuracy of results depends on amount of

data collected– Only change one variable ata time, keep allothers controlled

Experimentation, cont’d.• Two parts to an experiment:

– Control: the part of the experiment that stays the same

– Variable: the part of the experiment that is being tested• Independent Variable/Manipulated Variable

– The variable that scientists deliberately change

– Graphed on the X-axis• Dependent Variable/Responding Variable

– The variable that changes in response to the manipulated variable

– Graphed on the Y-axis

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.

PROCEDURE

Controlled Variables:jars, type of meat,location, temperature,time

Manipulated Variables:gauze covering thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appearResponding Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Redi’s Experiment

Apply It!Redi’s Experiment

• Observations: Flies land on meant that is left uncovered. After time, maggots appear on the meat.

• Hypothesis: Flies produce maggots.

• Controlled Variables: jars, types of meat, location, temperature, time

• Manipulated Variables: Gauze covering that keeps flies out of jars, away from meat

• Responding Variables: Whether maggots appear or not

• Conclusion: Maggots only form when flies come in contact with meat. There is no spontaneous generation of maggots.

5. Data- Record and Analyze

• Written records of their observation during the experiments (data)– Measurements (numbers, tick marks, etc.)– Observations (statements, notes, etc.)

• Graphs, charts are developed to show relationships within the data

Bell Ringer 8/22

Without using your notes try to answer the following questions in your science journal.

• What is the goal of science?• What is a hypothesis and in what form should it

presented?• List the steps of the Scientific Method. (Use your

mnuemonic)

Graphing Criteria• Things to do when graphing:

– Title– Label X and Y axis with variable label and units

• Numbering interval on each axis must be uniform

– Points are plotted neatly– “Best Fit” line for linear data, or smooth curves

for other data– Must be neat and legible– Use entire sheet of graph paper

• Line Graphs:– Frequently used in science– X axis always contains the independent or

manipulated data– Y axis contains the dependent or responding

variable.– Multiple related data sets can be graphed on

one graph• Must use a legend or key• Use different colors or line types

Types of Graphs

Cup Cakes Eaten per Minute

10152025303540

1 2 3 4

Time, (min)

Types of Graphs, cont’d.• Bar Graphs:

– Bar graphs are simplified versions of a line graph

– Bar graphs are most often used in business and in media (they are easier to read)

Cupcakes Eaten per Minute

1 2 3 4

Time, ( Min.)

JohnMarySeth

Type of Graphs, cont’d.

• Pie Charts:– Pie charts are used to show percentages– Remember: Sample / Total X 100 = %

40%25 yrs. old

30 yrs.old

35 yrs. old

40 yrs.old

Body Fat % in Men 25-40 Yrs. Old

Data Analysis• Data Table:

– Title on the table– Identify X and Y variable including units– Data collected in ordered pairs– Neat

The Change in Temperature Over Time

Time minutes

Temp.C

Let’s practice graphing

6. Come to a Conclusion

• The summary of all the information gathered in an experiment

• Restates the hypothesis• Identifies if the hypothesis was accepted or

rejected• Will identify at least 3 errors to the

experiment

• A key assumption in science is that experimental results can be reproduced.

• Therefore, scientists test one another’s investigations– Your procedure needs to be able to be

reproduced—your conclusion will not be accepted if it cannot be reproduced

7. Repeat and Publish Investigations

Fact, Theory, and Law• Fact

– A known truth about something– Ex: It is 85° outside

• Theory– The most logical explanation for an event in

nature – Based on careful observation and analysis– Must be dependable and reproducible

• Ex: The World is Flat• Law

– Describes an event– Summarizes repeated observations– Ex: Newton’s 3rd Law of Motion

A Scientific View of the World

• Scientists assume the universe obeys certain rules and those rules can be discovered and understood

• A good scientist should be curious, open minded, honest, and skeptical

The Study of Living Things

Characteristics of Life in the Scientific World

Learning TargetsSection 1-3: Studying Life

• List and describe the characteristics of living things

• Describe how life can be studied at different levels.

• Distinguish between living and non-living things

What is Biology?• We determined early in Chapter 1 that…

• BIO means…• LOGY means…

• Biology studies the living world – Using the Scientific Method

Characteristics of Living Things

• Biologists still debate today what it takes to constitute a living thing

• MOST agree that there are 8 characteristics that are common to living things

8 Common CharacteristicsLiving Things…

• Are made up of CELLS• REPRODUCE• Based on a universal GENETIC CODE• GROW AND DEVELOP• OBTAIN and USE materials and ENERGY• RESPOND to their environment• MAINTAIN stable living ENVIRONMENT• As a group, CHANGE OVER TIME

Lets Think of a mneumonic Device

This one does not have to have a specific order!

Be creative!

Use the letters:C, R, G, G, E, R, M & C

Living Things: Made of CELLS

• Cell: collection of living matter enclosed by a barrier that separates the cell from its surroundings

• Cells are the smallest units of an organism that can be considered alive

• Complex and highly organized

• Unicellular vs. Multicellular

Human Red Blood Cells

Living Things: REPRODUCE

• Two Basic Kinds of Reproduction:– Sexual Reproduction

• Two cells from different parents produce first cell of new organism

• Most multicellular organisms produce this way

– Asexual Reproduction• New organism is produced by a single parent• In some cases, a single-celled organism will

divide in half to form two new organisms• Other times, a new organism can grow out of

(or split off from) the existing organism--Budding

Living Things: Based on a GENETIC CODE

• Offspring usually resemble their parents

– In Asexual Reproduction, offspring and parents have the exact same traits

– In Sexual Reproduction, offspring differ from their parents (in limited ways)

Living Things:Genetic Code

• Directions for inheritance are carried by DNA (Deoxyribonucleic acid)

– With minor exceptions, DNA genetic code determines the inherited traits of EVERY organism on Earth!

Living Things:Grow and Develop

Living Things:GROW AND DEVELOP

• Every organism has a distinct life cycle—there is a set pattern of growth and change that occurs

• All organisms grow during at least part of their lives (increase in size)

• Multicellular organisms’ life cycles involve a process called development—cells increase in number and differentiate

• Development is LIMITED OR NON-EXISTENT in unicellular organisms

THINK- PAIR- SHARE• THINK- Close your notes and think about the

four characteristics of life we just discussed.

• PAIR- Turn to your partner and see if you can list them and explain what they mean.

• SHARE- You and your partner pair up with another group and share what you know about the four characteristics we just learned.

Living Things:OBTAIN AND USE ENERGY

• Organisms take in selected materials they need from their surroundings (environment)—BUT the way that they obtain energy varies– Plants from Sunlight, Sheep from Plants, etc.– Decomposers from remains of dead organisms

• Metabolism: Combination of chemical reactions through which organisms build up or break down materials required for life processes

Living Things:OBTAIN AND USE ENERGY

Living Things:RESPOND TO ENVIRONMENT

• Necessary because organisms live in constantly changing environments (light, temperature, etc)

• Each organism responds to the environment in their own way

• Some slow, some fast

• EX: New leaves and stems growing from a tree grow towards light

Living Things:RESPOND TO ENVIRONMENT

Living Things:Maintain Stable Internal Environment

• HOMEOSTASIS: Process by which organisms keep their internal environments relatively stable

• Ex: Plants can take in and give off water as needed

• If homeostasis is disrupted in a major way, the organism cannot survive

Living Things:CHANGE OVER TIME

• Basic traits of organisms stay the same over their lifetime

• Groups of organisms change over time, or EVOLVE– Occurs over hundreds of thousands or even millions

of years, not just a few generations– Usually in response to changes in their

environments

• Organisms naturally make changes over time to increase the species’ chances of survival

Living Things:Change Over Time

THINK PAIR SHARE• THINK- Close your notes and think about the four

characteristics of life we just discussed.

• PAIR- Turn to your partner and see if you can list them and explain what they mean.

• SHARE- Share with each other why it might be important for us to make a list of qualities that living things must share.

Concept CheckUsing what you know so far explain in your science journal how

the following pictures exhibits all of the characteristics of living things

• TURN IN YOUR RESPONSE

BRANCHES OF BIOLOGY• Biology is often organized into branches

– Some divisions are based on the type of organism being studied• Zoologists (study animals)• Botanists (study plants)• Ethologists (study animal behavior)

– Some divisions are based on the idea that life can be studied at different levels of organization

-Molecules -Populations-Cells -Communities-Groups of Cells -Ecosystems-Organisms -Biospheres

Biosphere

Ecosystem

Community

Population

The part of Earththat contains allecosystems

Community and its nonliving surroundings

Populations thatlive together in a defined area

Group of organisms of onetype that live in the same area

Biosphere

Hawk, snake, bison, prairie dog, grass, stream, rocks, air

Hawk, snake, bison, prairie dog, grass

Bison herd

Levels of Organization

Go to Section:

Organism

Groups ofCells

Molecules

Individual livingthing

Tissues, organs,and organ systems

Smallest functional unit of life

Groups of atoms;smallest unit of most chemicalcompounds

Nervous tissue Nervous systemBrain

Nerve cell

Water DNA

Go to Section:

HOW DOES BIOLOGY AFFECT ME?• More than any other science, Biology helps

you understand what affects the quality of your life

– What DOES affect the quality of your life?

1-4 Tools and Procedures

• Describe the measurementsystem most scientists use, and be able to make conversions

• Understand why it is necessary for scientists to use the same measurement system

• Explain how light microscopes and electron microscopes are similar and different

Learning TargetsSection 1-4: Tools and Procedures

Common Measurement System

• THE METRIC SYSTEM

– The metric system is the most widely used system of measurement in the world

– The United States is one of the two countries in the world that does not use the metric system (Burma is the other)

– System International is the governing body for the metric system (SI)

– The metric system is based on units of 10

Why the Same System?

• Scientists need a common system of measurement to be able to replicate others’ experiments, so they use the metric system when collecting DATA

Common Metric Units

Length-meter (m) Mass- gram (g)

1 meter = 100 centimeters (cm)1 meter = 1000 millimeters (mm)1000 meters = 1 kilometer (km)

1 kilogram (kg) = 1000 grams1 gram = 1000 milligrams (mg)1000 kilograms (kg) = 1 metric ton (t)

Volume-liter (L) Temperature-Celsius (°C)

1 liter = 1000 milliliters (mL)1 liter = 1000 cubic centimeters (cm3 or cc)

0°C= freezing point of water

100°C = boiling point of water

Name Meaning Abbr

Kilo X 1000 k

Hecta (Hecto) X 100 H

Deca X 10 D

Deci / 10 d

Centi / 100 c

Milli / 1000 m

Tera X 1012 T

Giga X 109 G

Pico X 10-12 p

Micro X 10-6 µ

Metric Prefixes

Metric Line

• Kiss Him/Her Dummy But Don’t Catch Mono

• Base units:– Meter (m)– Liter (L)– Gram (g)

k H D base unit d c mk H D base unit d c m

Metric Conversions• Metric Line

• Place finger on starting prefix• Place 2nd finger on ending prefix• Count the lines between fingers• Move the decimal place the # of lines

toward the 2nd finger• Add zeros to hold place

k H D base unit d c mk H D base unit d c m

Convert the following:• 1 km = ________ m• 12 mm = _______ cm• 4.2 L = _______ mL

Answers:• 1 km = 1000 m• 12 mm = 1.2 cm• 4.2 L = 4200mL

Microscopes

• Devices that produce magnified images of things too small to see with the unaided eye

• Two types– Light microscope– Electron

Compound Light Microscopes

• Magnify images by focusing visible light rays

• Advantage: view living things

• Disadvantage: Resolution limit is only 1000X

VIDEO CLIP!

Electron Microscopes• Magnify images by focusing electrons

• Advantage: higher resolution limit, about 100,000X normal size– 100X higher than a light microscope

• Disadvantage: Organisms must be stained and are in a vacuum (cannot view live specimens)

Two Types of Electron Microscopes

• Scanning electron microscopes (SEM)– Takes a 3-D view of the surface

• Transmission electron microscopes (TEM)– Beam of electrons passes through a thin slice– Specimens must stained and sliced

MICROSCOPES

According to the Video…

• On a sheet of paper, give me the two ways that Light Microscopes differ from Electron Microscopes

• TURN IT IN!

Laboratory Techniques for Studying Cells

• Cell Cultures– Grow cells in dish from a

single organism– Used to

• Test cell responses under controlled conditions

• Study interactions between cells

• Select specific cells for further study

Laboratory Techniques for Studying Cells, cont’d.

• Cell Fractionation– Method of separating the

pieces of broken cells

• Steps– Break cells apart– Add liquid and mix– Centrifuge to separate by

mass (spin very fast)

Cell Fractionation

Biologists can remove specific parts to be studied by selecting layer.

– Which of the following shows the interaction of science and human values? • the debate over the best way to produce

electricity• investigating how a manatee behaves• Determining what causes a disease• using a hypothesis to test an explanation

1–1– A possible explanation for a set of

observations is known as • data.• a hypothesis.• an inference.

• a result.

1–1– A good scientific hypothesis must

be• correct.• able to be tested.• obvious.• based on common sense.

1–2– In an experiment, the

variable that is deliberately changed is called the

•control.•manipulated variable.•responding variable.•constant control

1–2– The mistaken belief that

living organisms can arise from nonliving matter is called

•biogenesis.•Pasteur's theory.•spontaneous generation.•Spallanzani’s hypothesis.

1–2– Which of the following was the

manipulated variable in Redi’s experiment?

•the kind of meat used•the temperature the jars were

kept •the gauze covering on some jars

•the kind of fly that visited the jars

1–2– A well-tested explanation

that unifies a broad range of observations is a

•hypothesis.•variable.•control.•theory.

1–2– A scientific explanation does not

become a theory until

•a majority of scientists agree with it.

•it has been supported by evidence from numerous investigations and observations.

•it is first proposed as an explanation.

•it is published in a textbook.

1-3– An increase in size is known as

•growth.•metabolism.•development.•differentiation.

1-3– Which of the following is NOT a

characteristic of all living things?

•use of energy•made of cells•stable internal environment•need for oxygen

1-3– Which of the following are branches in the

study of biology?

•cells, tissues, organs, and organisms

•botany, cell biology, ecology, and zoology

•populations, communities, and ecosystems

•the genetic code, evolution, and the biosphere

1-3– The genetic code is carried ina. Water.b. DNA.c. proteins.d. soil.

1-3– Which of the following shows the levels of

organization in correct order from the simplest to the most complex?•organisms, cells, populations, molecules, ecosystems

•ecosystems, populations, organisms, cells, molecules

•molecules, cells, organisms, populations, ecosystems

•molecules, organisms, cells, populations, ecosystems

1-4– A single measurement system is commonly

used in science because

•it allows scientists to easily replicate one another’s experiments.

•basic units of mass, length, and volume are unrelated to one another.

•more kinds of measurements can be made.

•computers can store large amounts of scientific data.

1-4– Compared to a light microscope, an

electron microscope is used to observe

•larger objects with less detail.•larger objects with more detail.

•smaller objects with more detail.

•smaller objects with less detail.

1-4– A device that separates cell parts

•centrifuge.•cell culture.•light microscope.•electron microscope.

1-4– A technique in which cells are

grown in a nutrient solution is known as

•staining.•cell fractionation.•cell culturing.•cell fertilizing.

1-4– When you work in a biology laboratory

situation, your first priority should be to

•make sure all materials are available.

•modify any instructions that do not make sense.

•familiarize yourself with all safety rules before beginning to work.

•know ahead of time what kinds of results to expect.

Biology. The Science of Biology Chapter 1 1-1 What Is Science?

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